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MEMORY MAP Release 61 Last change 16jul00
Copyright (c) 1989-1999,2000 Ralf Brown
--------H-M00000000--------------------------
MEM 0000h:0000h R - INTERRUPT VECTOR TABLE
Size: 1024 BYTEs
Note: see also the main interrupt list
--------b-M0000031D--------------------------
MEM 0000h:031Dh - 1989 AMI 386sx BIOS - USER-DEFINABLE TYPE 47 HARD DISK PARMS
Size: 16 BYTEs
Note: these fields are used if the AMI BIOS setup is set to use the top of
the interrupt table for the extended BIOS data area
SeeAlso: MEM 0000h:032Dh,INT 41
--------b-M0000032D--------------------------
MEM 0000h:032Dh - 1989 AMI 386sx BIOS - USER-DEFINABLE TYPE 48 HARD DISK PARMS
Size: 16 BYTEs
Note: these fields are used if the AMI BIOS setup is set to use the top of
the interrupt table for the extended BIOS data area
SeeAlso: MEM 0000h:031Dh,INT 46
--------B-M00000400--------------------------
MEM 0000h:0400h - BIOS DATA AREA
Size: 256 BYTEs
Note: see also the MEM 0040h:xxxxh entries
----------M00000500--------------------------
MEM 0000h:0500h - DATA AREA
Size: 256 BYTEs
--------D-M00000600--------------------------
MEM 0000h:0600h - MS-DOS 1.x LOAD ADDRESS
--------D-M00000700--------------------------
MEM 0000h:0700h - MS-DOS 2+ LOAD ADDRESS
--------S-M00400000--------------------------
MEM 0040h:0000h - BASE I/O ADDRESS OF FIRST SERIAL I/O PORT
Size: WORD
Notes: the BIOS sets this word to zero if is unable to find any serial ports
at the addresses it is programmed to check at boot
DOS and BIOS serial device numbers may be redefined by re-assigning
these values of the base I/O addresses stored here
Under DR-OpenDOS 7.02+ this setting can be changed with the
undocumented CONFIG.SYS COM1=[port_address|logical_no][,[timeout]]
directive, whereby port_address = 200h..3F8h, logical_no = 0 or 1..4,
timeout=0..255 (default 1).
SeeAlso: MEM 0040h:0002h,MEM 0040h:0004h,MEM 0040h:0006h,MEM 0040h:0008h
SeeAlso: MEM 0040h:007Ch,INT 14/AH=00h,PORT 03F8h"SERIAL"
--------S-M00400002--------------------------
MEM 0040h:0002h - BASE I/O ADDRESS OF SECOND SERIAL I/O PORT
Size: WORD
Notes: the BIOS sets this word to zero if is unable to find more than one
serial port at the addresses it is programmed to check at boot
DOS and BIOS serial device numbers may be redefined by re-assigning
these values of the base I/O addresses stored here
Under DR-OpenDOS 7.02+ this setting can be changed with the
undocumented CONFIG.SYS COM2=[port_address|logical_no][,[timeout]]
directive, whereby port_address = 200h..3F8h, logical_no = 0 or 1..4,
timeout=0..255 (default 1).
SeeAlso: MEM 0040h:0000h,MEM 0040h:0004h,MEM 0040h:0006h,MEM 0040h:000Ah
SeeAlso: MEM 0040h:007Dh,INT 14/AH=00h,PORT 02F8h"SERIAL"
--------S-M00400004--------------------------
MEM 0040h:0004h - BASE I/O ADDRESS OF THIRD SERIAL I/O PORT
Size: WORD
Notes: the BIOS sets this word to zero if is unable to find more than two
serial ports at the addresses it is programmed to check at boot
Under DR-OpenDOS 7.02+ this setting can be changed with the
undocumented CONFIG.SYS COM3=[port_address|logical_no][,[timeout]]
directive, whereby port_address = 200h..3F8h, logical_no = 0 or 1..4,
timeout=0..255 (default 1).
SeeAlso: MEM 0040h:0000h,MEM 0040h:0002h,MEM 0040h:0006h,MEM 0040h:000Ch
SeeAlso: MEM 0040h:007Eh,PORT 03E8h"SERIAL"
--------S-M00400006--------------------------
MEM 0040h:0006h - BASE I/O ADDRESS OF FOURTH SERIAL I/O PORT
Size: WORD
Notes: the BIOS sets this word to zero if is unable to find more than three
serial ports at the addresses it is programmed to check at boot
Under DR-OpenDOS 7.02+ this setting can be changed with the
undocumented CONFIG.SYS COM4=[port_address|logical_no][,[timeout]]
directive, whereby port_address = 200h..3F8h, logical_no = 0 or 1..4,
timeout=0..255 (default 1).
SeeAlso: MEM 0040h:0000h,MEM 0040h:0002h,MEM 0040h:0004h,MEM 0040h:0008h
SeeAlso: MEM 0040h:007Fh,PORT 02E8h"SERIAL"
--------P-M00400008--------------------------
MEM 0040h:0008h - BASE I/O ADDRESS OF FIRST PARALLEL I/O PORT
Size: WORD
Notes: the BIOS POST routine fills in the parallel port address fields in
turn as it finds parallel ports. All fields beyond the last one
for which a valid parallel port was found are set to zero.
the BIOS INT 17 handler uses these fields to address the parallel
ports
Under DR-OpenDOS 7.02+ this setting can be changed with the
undocumented CONFIG.SYS LPT1=[port_address|logical_no][,[timeout]]
directive, whereby port_address = 200h..3FCh, logical_no = 0 or 1..3,
timeout=0..255 (default 20).
SeeAlso: MEM 0040h:0000h,MEM 0040h:000Ah,MEM 0040h:000Ch,INT 17/AH=00h
SeeAlso: PORT 0278h"PRINTER",PORT 03BCh"PRINTER"
--------P-M0040000A--------------------------
MEM 0040h:000Ah - BASE I/O ADDRESS OF SECOND PARALLEL I/O PORT
Size: WORD
Notes: zero if fewer than two parallel ports installed
Under DR-OpenDOS 7.02+ this setting can be changed with the
undocumented CONFIG.SYS LPT2=[port_address|logical_no][,[timeout]]
directive, whereby port_address = 200h..3FCh, logical_no = 0 or 1..3,
timeout=0..255 (default 20).
SeeAlso: MEM 0040h:0002h,MEM 0040h:0008h,MEM 0040h:000Ch,PORT 0278h"PRINTER"
SeeAlso: PORT 0378h"PRINTER",INT 17/AH=00h
--------P-M0040000C--------------------------
MEM 0040h:000Ch - BASE I/O ADDRESS OF THIRD PARALLEL I/O PORT
Size: WORD
Notes: zero if fewer than three parallel ports installed
Under DR-OpenDOS 7.02+ this setting can be changed with the
undocumented CONFIG.SYS LPT3=[port_address|logical_no][,[timeout]]
directive, whereby port_address = 200h..3FCh, logical_no = 0 or 1..3,
timeout=0..255 (default 20).
SeeAlso: MEM 0040h:0004h,MEM 0040h:0008h,MEM 0040h:000Ah,MEM 0040h:000Eh
SeeAlso: PORT 0378h"PRINTER",INT 17/AH=00h
--------P-M0040000E--------------------------
MEM 0040h:000Eh - BASE I/O ADDRESS OF FOURTH PARALLEL I/O PORT (pre-PS/2)
Size: WORD
Notes: zero if fewer than four parallel ports installed
Under DR-OpenDOS 7.02+ this setting can be changed with the
undocumented CONFIG.SYS LPT4=(port_address|logical_no)[,[timeout]]
directive, where port_address = 200h..3FCh, logical_no = 0 or 1..3,
timeout=0..255 (default 20). To avoid any interference with the PS/2
and later interpretation, this will be rejected if this entry does
not hold 0, which would indicate it is used for different purposes.
SeeAlso: MEM 0040h:0008h,MEM 0040h:000Ah,MEM 0040h:000Eh"BIOS DATA"
SeeAlso: PORT 0378h"PRINTER",INT 17/AH=00h
--------B-M0040000E--------------------------
MEM 0040h:000Eh - SEGMENT OF EXTENDED BIOS DATA SEGMENT (PS/2, newer BIOSes)
Size: WORD
SeeAlso: MEM 0040h:000Eh"PARALLEL",INT 15/AH=C1h
Format of Extended BIOS Data Area (IBM):
Offset Size Description (Table M0001)
00h BYTE length of EBDA in kilobytes
01h 15 BYTEs reserved
17h BYTE number of entries in POST error log (0-5)
18h 5 WORDs POST error log (each word is a POST error number)
22h DWORD Pointing Device Driver entry point
26h BYTE Pointing Device Flags 1 (see #M0002)
27h BYTE Pointing Device Flags 2 (see #M0003)
28h 8 BYTEs Pointing Device Auxiliary Device Data
30h DWORD Vector for INT 07h stored here during 80387 interrupt
34h DWORD Vector for INT 01h stored here during INT 07h emulation
38h BYTE Scratchpad for 80287/80387 interrupt code
39h WORD Timer3: Watchdog timer initial count
3Bh BYTE ??? seen non-zero on Model 30
3Ch BYTE ???
3Dh 16 BYTEs Fixed Disk parameter table for drive 0 (for older machines
which don't directly support the installed drive)
4Dh 16 BYTEs Fixed Disk parameter table for drive 1 (for older machines
which don't directly support the installed drive)
5Dh-67h ???
68h BYTE cache control
bits 7-2 unused (0)
bit 1: CPU cache failed test
bit 0: CPU cache disabled
69h-6Bh ???
6Ch BYTE Fixed disk: (=FFh on ESDI systems)
bits 7-4: Channel number 00-0Fh
bits 3-0: DMA arbitration level 00-0Eh
6Dh BYTE ???
6Eh WORD current typematic setting (see INT 16/AH=03h)
70h BYTE number of attached hard drives
71h BYTE hard disk 16-bit DMA channel
72h BYTE interrupt status for hard disk controller (1Fh on timeout)
73h BYTE hard disk operation flags
bit 7: controller issued operation-complete INT 76h
bit 6: controller has been reset
bits 5-0: unused (0)
74h DWORD old INT 76h vector
78h BYTE hard disk DMA type
typically 44h for reads and 4Ch for writes
79h BYTE status of last hard disk operation
7Ah BYTE hard disk timeout counter
7Bh-7Dh
7Eh 8 WORDs storage for hard disk controller status
8Eh-E6h
E7h BYTE floppy drive type
bit 7: drive(s) present
bits 6-2: unused (0)
bit 1: drive 1 is 5.25" instead of 3.5"
bit 0: drive 0 is 5.25"
E8h 4 BYTEs ???
ECh BYTE hard disk parameters flag
bit 7: parameters loaded into EBDA
bits 6-0: unused (0)
EDh BYTE ???
EEh BYTE CPU family ID (03h = 386, 04h = 486, etc.) (see INT 15/AH=C9h)
EFh BYTE CPU stepping (see INT 15/AH=C9h)
F0h 39 BYTEs ???
117h WORD keyboard ID (see INT 16/AH=0Ah)
(most commonly 41ABh)
119h BYTE ???
11Ah BYTE non-BIOS INT 18h flag
bits 7-1: unused (0)
bit 0: set by BIOS before calling user INT 18h at offset 11Dh
11Bh 2 BYTE ???
11Dh DWORD user INT 18h vector if BIOS has re-hooked INT 18h
121h and up: ??? seen non-zero on Model 60
3F0h BYTE Fixed disk buffer (???)
SeeAlso: #M0004
Bitfields for Pointing Device Flags 1:
Bit(s) Description (Table M0002)
7 command in progress
6 resend byte (FAh) received
5 acknowledge byte (FEh) received
4 error byte (FCh) received
3 unexpected value received
2-0 index count for auxiliary device data at 28h
SeeAlso: #M0001,#M0003
Bitfields for Pointing Device Flags 2:
Bit(s) Description (Table M0003)
7 device driver far call flag
6-3 reserved
2-0 package size (number of bytes received) - 1
SeeAlso: #M0001,#M0002
Format of Extended BIOS Data Area (AMI v1.00.12.AX1T):
Offset Size Description (Table M0004)
00h BYTE length of XBDA in kilobytes
01h 15 BYTEs reserved
17h BYTE number of entries in POST error log (0-10)
18h 10 BYTEs unused???
22h DWORD Pointing Device Driver entry point
26h BYTE Pointing Device Flags 1 (see #M0002)
27h BYTE Pointing Device Flags 2 (see #M0003)
28h 8 BYTEs Pointing Device Auxiliary Device Data
30h 13 BYTEs ???
3Dh 16 BYTEs Fixed Disk parameter table for drive 0
4Dh 16 BYTEs Fixed Disk parameter table for drive 1
5Dh 16 BYTEs parameter table for drive 2???
6Dh 16 BYTEs parameter table for drive 3???
80h 56 BYTEs? IDE drive 0 manufacturer/model string
B8h 41 BYTEs AMIBIOS copyright string
E1h unused???
102h WORD ??? flags
bit 15: ???
108h WORD offset of IntelIDECfgTbl (IDE configuration settings) within
segment F000h
10Ah 2 BYTEs ???
10Ch DWORD pointer to routine to call for language-specific error messages
110h WORD offset in segment F000h of end of currently-loaded optional
BIOS subsystems (language, APM, etc.)
112h WORD offset in segment F000h of end of area avaiable for loading
optional BIOS subsystems
1F0h BYTE APM status flags
1F1h 8 BYTEs APM power-state data for device classes 01h-06h
bits 0-3: current power state for devices 00h-03h in class
bits 7-4: current engaged state for devices 00h-03h in class
1F9h 4 BYTEs APM power-state data for device classes 01h-08h (four devices
per class)
1FDh 3 BYTEs ???
200h 10 WORDs POST error log
214h ???
SeeAlso: #M0001,#M0005
Format of Extended BIOS Data Area (PhoenixBIOS 4.0):
Offset Size Description (Table M0005)
00h BYTE length of XBDA in kilobytes
01h 33 BYTEs reserved
22h DWORD Pointing Device Driver entry point
26h BYTE Pointing Device Flags 1 (see #M0002)
27h BYTE Pointing Device Flags 2 (see #M0003)
28h 8 BYTEs Pointing Device Auxiliary Device Data
SeeAlso: #M0001,#M0004
--------B-M00400010--------------------------
MEM 0040h:0010h - INSTALLED HARDWARE
Size: WORD
SeeAlso: INT 11
Bitfields for BIOS-detected installed hardware:
Bit(s) Description (Table M0006)
15-14 number of parallel devices
00 or 11 sometimes used to indicate four LPT ports
13 (Convertible, PS/2-55LS) internal modem
12 game port installed
11-9 number of serial devices
000 or 111 sometimes used to indicate eight COM ports
8 reserved
7-6 number of floppy disk drives (minus 1)
5-4 initial video mode
00 EGA,VGA,PGA, or other with on-board video BIOS
01 40x25 CGA color
10 80x25 CGA color
11 80x25 mono text
3-2 (PC only) RAM on motherboard
00 = 16K, 01 = 32K, 10 = 48K, 11 = 64K
(some XTs) RAM on motherboard
00 = 64K, 01 = 128K, 10 = 192K, 11 = 256K
2 (pre-PS/2 except PC) reserved
(PS/2, some XT clones, newer BIOSes) pointing device installed
1 math coprocessor installed
0 floppy disk drives are installed
booted from floppy
--------B-M00400012--------------------------
MEM 0040h:0012h - Convertible - POST STATUS
Size: BYTE
--------B-M00400012--------------------------
MEM 0040h:0012h U - AT - MANUFACTURING TEST INITIALIZATION FLAGS
Size: BYTE
Bitfields for AT manufacturing test initialization flags:
Bit(s) Description (Table M0007)
0 start in manufacturing test mode rather than normal operation
1-7 unused
--------b-M00400012--------------------------
MEM 0040h:0012h - MCA - MANUFACTURING TEST
Size: BYTE
Bitfields for MCA manufacturing test flags :
Bit(s) Description (Table M0008)
7 POST flag, ???
6-5 unused
4 POST flag, slot 4 has adapter identifier EDAFh
3 POST flag, 80x25 color video
2 POST flag, ???
1 unused
0 manufacturing test mode rather than normal operation
--------b-M00400012--------------------------
MEM 0040h:0012h - PS/2 Model 25 - POST SYSTEM FLAG
Size: BYTE
Bitfields for PS/2 Model 25 POST sytem flag :
Bit(s) Description (Table M0009)
0 optional memory failed; memory remapped
1 real-time clock installed
--------B-M00400013--------------------------
MEM 0040h:0013h - BASE MEMORY SIZE IN KBYTES
Size: WORD
SeeAlso: INT 12
--------b-M00400015--------------------------
MEM 0040h:0015h - PC, XT - ADAPTER MEMORY SIZE IN KBYTES
Size: WORD
--------b-M00400015--------------------------
MEM 0040h:0015h U - AT - MANUFACTURING TEST SCRATCH PAD
Size: BYTE
--------K-M00400015--------------------------
MEM 0040h:0015h - Compaq Deskpro 386 - PREVIOUS SCAN CODE
Size: BYTE
--------b-M00400016--------------------------
MEM 0040h:0016h U - AT - MANUFACTURING TEST SCRATCH PAD
Size: BYTE
--------b-M00400016--------------------------
MEM 0040h:0016h U - PS/2 Model 30 - BIOS CONTROL FLAGS
Size: BYTE
--------K-M00400016--------------------------
MEM 0040h:0016h - Compaq Deskpro 386 - KEYCLICK VOLUME
Size: BYTE
Range: 00h-7Fh
--------K-M00400017--------------------------
MEM 0040h:0017h - KEYBOARD - STATUS FLAGS 1
Size: BYTE
SeeAlso: MEM 0040h:0018h,INT 16/AH=02h,MEM 0040h:0096h
Bitfields for keyboard status flags 1:
Bit(s) Description (Table M0010)
7 INSert active
6 Caps Lock active
5 Num Lock active
4 Scroll Lock active
3 either Alt pressed
2 either Ctrl pressed
1 Left Shift pressed
0 Right Shift pressed
SeeAlso: #M0011,#00587
--------K-M00400018--------------------------
MEM 0040h:0018h - KEYBOARD - STATUS FLAGS 2
Size: BYTE
SeeAlso: MEM 0040h:0017h,INT 16/AH=12h
Bitfields for keyboard status flags 2 :
Bit(s) Description (Table M0011)
7 INSert pressed
6 Caps Lock pressed
5 Num Lock pressed
4 Scroll Lock pressed
3 Pause state active
2 Sys Req pressed
1 Left Alt pressed
0 Left Ctrl pressed
SeeAlso: #M0010,#00588
--------K-M00400019--------------------------
MEM 0040h:0019h - KEYBOARD - ALT-nnn KEYPAD WORKSPACE
Size: BYTE
Desc: holds the current value of an Alt-NNN keypad sequence; when Alt is
released and this byte is non-zero, the appropriate character is
placed in the keyboard buffer
SeeAlso: INT 16/AH=00h,MEM 0040h:001Ah
--------K-M0040001A--------------------------
MEM 0040h:001Ah - KEYBOARD - POINTER TO NEXT CHARACTER IN KEYBOARD BUFFER
Size: WORD
SeeAlso: MEM 0040h:001Ch,MEM 0040h:0080h,MEM 0040h:0082h,INT 16/AH=00h
--------K-M0040001C--------------------------
MEM 0040h:001Ch - KEYBOARD - POINTER TO FIRST FREE SLOT IN KEYBOARD BUFFER
Size: WORD
SeeAlso: MEM 0040h:001Ah,MEM 0040h:001Eh,MEM 0040h:0080h,MEM 0040h:0082h
SeeAlso: INT 16/AH=00h
--------K-M0040001E--------------------------
MEM 0040h:001Eh - KEYBOARD - DEFAULT KEYBOARD CIRCULAR BUFFER
Size: 16 WORDs
SeeAlso: MEM 0040h:001Ah,MEM 0040h:001Ch,MEM 0040h:0080h,MEM 0040h:0082h
SeeAlso: INT 16/AH=00h,INT 16/AH=05h
--------B-M0040003E--------------------------
MEM 0040h:003Eh - DISKETTE - RECALIBRATE STATUS
Size: BYTE
SeeAlso: MEM 0040h:003Fh,MEM 0040h:0040h,INT 13/AH=00h,INT 13/AH=11h
Bitfields for diskette recalibrate status:
Bit(s) Description (Table M0012)
7 diskette hardware interrupt occurred
6-4 reserved
3 recalibrate diskette 3 (PC,XT only)
2 recalibrate diskette 2 (PC,XT only)
1 recalibrate diskette 1
0 recalibrate diskette 0
--------B-M0040003F--------------------------
MEM 0040h:003Fh - DISKETTE - MOTOR STATUS
Size: BYTE
SeeAlso: MEM 0040h:003Eh,MEM 0040h:0040h
Bitfields for diskette motor status:
Bit(s) Description (Table M0013)
7 current operation is write or format, rather than read or verify
6 reserved (DMA enabled on 82077)
5-4 diskette drive number selected (0-3)
3 diskette 3 motor on (PC,XT only)
2 diskette 2 motor on (PC,XT only)
1 diskette 1 motor on
0 diskette 0 motor on
--------B-M00400040--------------------------
MEM 0040h:0040h - DISKETTE - MOTOR TURN-OFF TIMEOUT COUNT
Size: BYTE
Desc: number of clock ticks until diskette motor is turned off
Note: the typical implementation of the timeout is to have the INT 08
handler decrement this byte on every clock tick, and force the
diskette motor off if the result is equal to zero
SeeAlso: MEM 0040h:003Eh,MEM 0040h:003Fh,MEM 0040h:0041h,INT 08"IRQ0"
--------B-M00400041--------------------------
MEM 0040h:0041h - DISKETTE - LAST OPERATION STATUS
Size: BYTE
SeeAlso: MEM 0040h:003Eh,MEM 0040h:0042h,INT 13/AH=01h
Bitfields for diskette last operation status:
Bit(s) Description (Table M0014)
7 drive not ready
6 seek error
5 general controller failure
4-0 error reason
00h no error
01h invalid request/parameter
02h address mark not found
03h write-protect error
04h sector not found
06h diskette change line active
08h DMA overrun
09h DMA across 64k boundary
0Ch media type unknown
10h CRC error on read
Note: the following values for this byte differ somewhat from the
bitfield definition above:
30h drive does not support media sense
31h no media in drive
32h drive does not support media type
AAh diskette drive not ready
--------B-M00400042--------------------------
MEM 0040h:0042h - DISK - FLOPPY/HARD DRIVE STATUS/COMMAND BYTES
Size: 7 BYTEs
SeeAlso: MEM 0040h:0041h
42h BYTE XT: command byte to hard disk controller
AT: write precompensation cylinder number / 4
43h BYTE XT: bit 5 = drive number, bits 3-0=head number
AT: sector count
44h BYTE XT: bits 6,7 = high bits of track, bits 5-0 = start sector-1
AT: starting sector
45h BYTE low byte of track number
46h BYTE XT: sector count
AT: high bits of track number
47h BYTE XT: controlbyte from HD parameters (step rate,...)
AT: 101DHHHH, D=drive number, HHHH=head number
bit 7 = ECC mode (1)
bit 6 = unknown (0)
bit 5 = 512 byte sectors (1)
bit 4 = drive number
bit 3-0 head number
48h BYTE XT: INT 13h subfunction number
AT: command byte to hard disk controller
SeeAlso: CALL F000h:211Eh
--------B-M00400042--------------------------
MEM 0040h:0042h - DISK CONTROLLER STATUS REGISTER 0
Size: BYTE
SeeAlso: MEM 0040h:0043h
Bitfields for diskette controller status register 0:
Bit(s) Description (Table M0015)
7-6 interrupt code
00 normal completion
01 abnormal termination during execution
10 invalid command
11 abnormal termination: ready line on/diskette change
5 requested seek complete
4 drive fault
3 drive not ready
2 head state at time of interrupt
1-0 selected drive (drives 2&3 on PC,XT only)
SeeAlso: #M0016
--------B-M00400043--------------------------
MEM 0040h:0043h - DISK CONTROLLER STATUS REGISTER 1
Size: BYTE
SeeAlso: MEM 0040h:0042h,MEM 0040h:0044h
Bitfields for diskette controller status register 0:
Bit(s) Description (Table M0016)
7 attempted access beyon last cylinder
6 unused
5 CRC error on read
4 DMA overrun
3 unused
2 data error
1 disk write protected
0 missing address mark
SeeAlso: #M0015,#M0017
--------B-M00400044--------------------------
MEM 0040h:0044h - DISK CONTROLLER STATUS REGISTER 2
Size: BYTE
SeeAlso: MEM 0040h:0043h
Bitfields for diskette controller status register 0:
Bit(s) Description (Table M0017)
7 unused
6 found deleted data address mark
5 CRC error in data field
4 wrong cylinder number read
3 verify equal
2 can't find sector matching verify condition
1 bad cylinder
0 unable to find address mark
SeeAlso: #M0016
--------V-M00400049--------------------------
MEM 0040h:0049h - VIDEO - CURRENT VIDEO MODE
Size: BYTE
SeeAlso: MEM 0040h:004Ah,INT 10/AH=00h
--------V-M0040004A--------------------------
MEM 0040h:004Ah - VIDEO - COLUMNS ON SCREEN
Size: WORD
SeeAlso: MEM 0040h:0049h,MEM 0040h:004Ch,MEM 0040h:004Eh,INT 10/AH=0Fh
--------V-M0040004C--------------------------
MEM 0040h:004Ch - VIDEO - PAGE (REGEN BUFFER) SIZE IN BYTES
Size: WORD
SeeAlso: MEM 0040h:004Ah,MEM 0040h:004Eh,MEM 0040h:0050h
--------V-M0040004E--------------------------
MEM 0040h:004Eh - VIDEO - CURRENT PAGE START ADDRESS IN REGEN BUFFER
Size: WORD
SeeAlso: MEM 0040h:004Ch,MEM 0040h:0050h,MEM 0040h:0062h,INT 10/AH=05h
--------V-M00400050--------------------------
MEM 0040h:0050h - VIDEO - CURSOR POSITIONS
Size: 8 WORDs
Desc: contains row and column position for the cursors on each of eight
video pages
SeeAlso: MEM 0040h:004Eh,MEM 0040h:0060h,INT 10/AH=02h
--------V-M00400060--------------------------
MEM 0040h:0060h - VIDEO - CURSOR TYPE
Size: WORD (big-endian)
Desc: contains cursor start scan line and cursor end scan line
SeeAlso: MEM 0040h:0050h,MEM 0040h:0062h,INT 10/AH=03h
--------V-M00400062--------------------------
MEM 0040h:0062h - VIDEO - CURRENT PAGE NUMBER
Size: BYTE
SeeAlso: MEM 0040h:004Eh,MEM 0040h:0063h,INT 10/AH=05h
--------V-M00400063--------------------------
MEM 0040h:0063h - VIDEO - CRT CONTROLLER BASE I/O PORT ADDRESS
Size: WORD
Note: normally 03B4h for mono and 03D4h for color video boards
SeeAlso: MEM 0040h:0065h,MEM 0040h:0066h
--------V-M00400065--------------------------
MEM 0040h:0065h - VIDEO - CURRENT MODE SELECT REGISTER
Size: BYTE
Desc: contains last value written to I/O port 03B8h / 03D8h
SeeAlso: MEM 0040h:0063h,MEM 0040h:0066h
Bitfields for current video mode select register:
Bit(s) Description (Table M0018)
7-6 unused
5 attribute bit 7 controls blinking instead of background
4 mode 6 graphics in monochrome
3 video signal enabled
2 monochrome
1 graphics
0 80x25 text
--------V-M00400066--------------------------
MEM 0040h:0066h - VIDEO - CURRENT SETTING OF CGA PALETTE REGISTER
Size: BYTE
Desc: contains the last value written to I/O port 03D9h
SeeAlso: MEM 0040h:0063h,MEM 0040h:0065h,INT 10h/AH=0Bh/BH=01h
Bitfields for CGA palette register:
Bit(s) Description (Table M0019)
7-6 unused
5 palette (0/1)
4 intense background colors in text mode
3 intense border color (40x25) / background color (mode 5)
2 red
1 green
0 blue
----------M00400067--------------------------
MEM 0040h:0067h - PC only - CASSETTE TIME COUNT
Size: WORD
SeeAlso: INT 15/AH=00h
----------M00400067--------------------------
MEM 0040h:0067h - RESET RESTART ADDRESS
Size: DWORD
Desc: this address stores the address at which to resume execution after a
CPU reset (or jump to F000h:FFF0h) when certain magic values are
stored at 0040h:0072h or in CMOS RAM location 0Fh
SeeAlso: MEM 0040h:0072h,MEM F000h:FFF0h,CMOS 0Fh,INT 19
----------M00400069--------------------------
MEM 0040h:0069h - CASSETTE (PC only) - CASSETTE CRC REGISTER
Size: WORD
SeeAlso: MEM 0040h:006Bh"CASSETTE",INT 15/AH=02h
----------M00400069--------------------------
MEM 0040h:0069h - V20-XT-BIOS - KEY REPEAT
Size: BYTE
Bitfields for V20-XT-BIOS key repeat flags:
Bit(s) Description (Table M0020)
7 key repeat disabled
6 Ctrl-Alt pressed instead of just Alt
----------M0040006B--------------------------
MEM 0040h:006Bh - CASSETTE (PC only) - LAST VALUE READ FROM CASSETTE
Size: BYTE
SeeAlso: MEM 0040h:0069h"CASSETTE",INT 15/AH=02h
----------M0040006B--------------------------
MEM 0040h:006Bh - POST LAST UNEXPECTED INTERRUPT (XT and later)
Size: BYTE
Desc: this is a bitmask of IRQs which have occurred while the corresponding
interrupt vector points at the default system BIOS handler
(bit 0 = IRQ0 to bit 7 = IRQ7; bit 2 = IRQ8-15 on AT and later)
SeeAlso: INT 0F"IRQ7",INT 70"IRQ8",INT 77"IRQ15"
----------M0040006C--------------------------
MEM 0040h:006Ch - TIMER TICKS SINCE MIDNIGHT
Size: DWORD
Desc: updated approximately every 55 milliseconds by the BIOS INT 08 handler
SeeAlso: MEM 0040h:0070h,INT 08"IRQ0",INT 1A/AH=00h
----------M00400070--------------------------
MEM 0040h:0070h - TIMER OVERFLOW
Size: BYTE
Desc: non-zero if timer has counted past midnight since last call to
INT 1A/AH=00h
Note: the original IBM BIOS, and thus most other BIOSes, sets this byte to
01h at midnight; a few (such as the Eagle PC-2) increment it each
time midnight is passed. The former behavior results in lost days
if multiple midnights pass between "get-time" calls while the machine
is powered up.
SeeAlso: MEM 0040h:006Ch,INT 1A/AH=00h
--------K-M00400071--------------------------
MEM 0040h:0071h - Ctrl-Break FLAG
Size: BYTE
Desc: bit 7 is set when Ctrl-Break has been pressed
SeeAlso: INT 1B
----------M00400072--------------------------
MEM 0040h:0072h - POST RESET FLAG
Size: WORD
Desc: specify the action the BIOS should take at the beginning of the
power-on self-test when the machine is reset
SeeAlso: INT 19,MEM F000h:FFF0h
(Table M0021)
Values for POST reset flag:
0000h cold boot
0064h Burn-in mode
1234h to bypass memory test (warm boot)
4321h [PS/2 except Mod 25,30] to preserve memory
5678h [Conv] system suspended
9ABCh [Conv] manufacturing test mode
ABCDh [Conv] POST loop mode
--------B-M00400074--------------------------
MEM 0040h:0074h - FIXED DISK LAST OPERATION STATUS (except ESDI drives)
Size: BYTE
SeeAlso: INT 13/AH=01h,INT 13h/AH=0Ah,MEM 0040h:0041h
(Table M0022)
Values for fixed disk last operation status:
00h no error
01h invalid function request
02h address mark not found
03h write protect error
04h sector not found
05h reset failed
06h diskette removed
07h drive parameter activity failed
08h DMA overrun
09h DMA data boundary error
0Ah bad sector flag detected
0Bh bad track detected
0Ch requested diskette media type not found
(PS/2 or extended BIOS only) unsupported track
0Dh invalid number of sectors for Format
0Eh control data address mark detected
0Fh DMA arbitration level out of range
10h uncorrectable ECC or CRC error
11h ECC corrected data error
20h general controller failed
40h seek failed
80h time out
AAh drive not ready
B0h volume not locked in drive (INT 13 extensions)
B1h volume locked in drive (INT 13 extensions)
B2h volume not removable (INT 13 extensions)
B3h volume in use (INT 13 extensions)
B4h lock count exceeded (INT 13 extensions)
B5h valid eject request failed (INT 13 extensions)
BBh undefined error
CCh write fault on selected drive
E0h status error/error register is zero
FFh sense failed
SeeAlso: #00234
--------d-M00400074--------------------------
MEM 0040h:0074h - WD1002-27X SuperBIOS - TOTAL DRIVES, FIRST CONTROLLER ONLY
Size: BYTE
SeeAlso: MEM 0040h:0075h"SuperBIOS",MEM 0040h:0076h"SuperBIOS"
--------B-M00400075--------------------------
MEM 0040h:0075h - FIXED DISK - NUMBER OF FIXED DISK DRIVES
Size: BYTE
SeeAlso: MEM 0040h:0076h"FIXED DISK",MEM 0040h:0077h"FIXED DISK"
--------d-M00400075--------------------------
MEM 0040h:0075h - WD1002-27X SuperBIOS - TOTAL FIXED DRIVES, BOTH CONTROLLERS
Size: BYTE
SeeAlso: MEM 0040h:0074h"SuperBIOS",MEM 0040h:0076h"SuperBIOS"
--------B-M00400076--------------------------
MEM 0040h:0076h - FIXED DISK - CONTROL BYTE {IBM documented only for XT}
Size: BYTE
Desc: loaded from the disk parameter table control byte (offset 8) during
various hard disk operations
SeeAlso: MEM 0040h:0075h"FIXED DISK",MEM 0040h:0077h"FIXED DISK"
--------d-M00400076--------------------------
MEM 0040h:0076h - XT: hard disk controller's I/O address (Western Digital)
Size: BYTE
--------d-M00400076--------------------------
MEM 0040h:0076h - WD1002-27X SuperBIOS - USED IN TRACK RECALCULATION
Size: BYTE
SeeAlso: MEM 0040h:0074h"SuperBIOS",MEM 0040h:0075h"SuperBIOS"
SeeAlso: MEM 0040h:0077h"SuperBIOS"
--------B-M00400077--------------------------
MEM 0040h:0077h - FIXED DISK - I/O port offset {IBM documented only for XT}
Size: BYTE
SeeAlso: MEM 0040h:0075h"FIXED DISK",MEM 0040h:0076h"FIXED DISK"
--------d-M00400077--------------------------
MEM 0040h:0077h - WD1002-27X SuperBIOS - USED IN TRACK RECALCULATION
Size: BYTE
SeeAlso: MEM 0040h:0076h"SuperBIOS"
--------B-M00400078--------------------------
MEM 0040h:0078h - PARALLEL DEVICE 1 TIME-OUT COUNTER
Size: BYTE
Note: Under DR-OpenDOS 7.02+ this setting can be changed with the
undocumented CONFIG.SYS LPT1=[port_address|logical_no][,[timeout]]
directive, whereby port_address = 200h..3FCh, logical_no = 0 or 1..3,
timeout=0..255 (default 20).
SeeAlso: MEM 0040h:0079h,MEM 0040h:007Ah,INT 17/AH=00h
--------B-M00400079--------------------------
MEM 0040h:0079h - PARALLEL DEVICE 2 TIME-OUT COUNTER
Size: BYTE
Note: Under DR-OpenDOS 7.02+ this setting can be changed with the
undocumented CONFIG.SYS LPT2=[port_address|logical_no][,[timeout]]
directive, whereby port_address = 200h..3FCh, logical_no = 0 or 1..3,
timeout=0..255 (default 20).
SeeAlso: MEM 0040h:0078h,MEM 0040h:007Ah,INT 17/AH=00h
--------B-M0040007A--------------------------
MEM 0040h:007Ah - PARALLEL DEVICE 3 TIME-OUT COUNTER
Size: BYTE
Note: Under DR-OpenDOS 7.02+ this setting can be changed with the
undocumented CONFIG.SYS LPT3=[port_address|logical_no][,[timeout]]
directive, whereby port_address = 200h..3FCh, logical_no = 0 or 1..3,
timeout=0..255 (default 20).
SeeAlso: MEM 0040h:0078h,MEM 0040h:0079h,MEM 0040h:007Bh"PARALLEL"
--------B-M0040007B--------------------------
MEM 0040h:007Bh - PARALLEL DEVICE 4 TIME-OUT COUNTER (pre-PS, PS Models 25,30)
Size: BYTE
Note: Under DR-OpenDOS 7.02+ this setting can be changed with the
undocumented CONFIG.SYS LPT4=(port_address|logical_no)[,[timeout]]
directive, where port_address = 200h..3FCh, logical_no = 0 or 1..3,
timeout=0..255 (default 20). To avoid any interference with the PS/2
and later interpretation, this will be rejected if this entry does
not hold 0, which would indicate it is used for different purposes.
SeeAlso: MEM 0040h:0078h,MEM 0040h:007Ah,MEM 0040h:007Bh"INT 4Bh"
--------m-M0040007B--------------------------
MEM 0040h:007Bh - INT 4Bh FLAGS (PS2 and newer)
Size: BYTE
SeeAlso: INT 4B/AX=8102h
Bitfields for INT 4Bh flags:
Bit(s) Description (Table M0023)
7-6 reserved
5 set if Virtual DMA Spec supported [PS] (see INT 4B)
4 reserved
3 set if INT 4Bh intercepted and must be chained
2 reserved
1 set if Generic SCSI CBIOS services available on INT 4Bh
0 reserved
--------B-M0040007C--------------------------
MEM 0040h:007Ch - SERIAL DEVICE 1 TIMEOUT COUNTER
Size: BYTE
Note: Under DR-OpenDOS 7.02+ this setting can be changed with the
undocumented CONFIG.SYS COM1=[port_address|logical_no][,[timeout]]
directive, whereby port_address = 200h..3F8h, logical_no = 0 or 1..4,
timeout=0..255 (default 1).
SeeAlso: MEM 0040h:0000h,MEM 0040h:007Dh,MEM 0040h:007Eh,MEM 0040h:007Fh
SeeAlso: INT 14/AH=01h
--------B-M0040007D--------------------------
MEM 0040h:007Dh - SERIAL DEVICE 2 TIMEOUT COUNTER
Size: BYTE
Note: Under DR-OpenDOS 7.02+ this setting can be changed with the
undocumented CONFIG.SYS COM2=[port_address|logical_no][,[timeout]]
directive, whereby port_address = 200h..3F8h, logical_no = 0 or 1..4,
timeout=0..255 (default 1).
SeeAlso: MEM 0040h:0002h,MEM 0040h:007Ch,MEM 0040h:007Eh,MEM 0040h:007Fh
SeeAlso: INT 14/AH=01h
--------B-M0040007E--------------------------
MEM 0040h:007Eh - SERIAL DEVICE 3 TIMEOUT COUNTER
Size: BYTE
Note: Under DR-OpenDOS 7.02+ this setting can be changed with the
undocumented CONFIG.SYS COM3=[port_address|logical_no][,[timeout]]
directive, whereby port_address = 200h..3F8h, logical_no = 0 or 1..4,
timeout=0..255 (default 1).
SeeAlso: MEM 0040h:0004h,MEM 0040h:007Ch,MEM 0040h:007Dh,MEM 0040h:007Fh
SeeAlso: INT 14/AH=01h
--------B-M0040007F--------------------------
MEM 0040h:007Fh - SERIAL DEVICE 4 TIMEOUT COUNTER
Size: BYTE
Note: Under DR-OpenDOS 7.02+ this setting can be changed with the
undocumented CONFIG.SYS COM4=[port_address|logical_no][,[timeout]]
directive, whereby port_address = 200h..3F8h, logical_no = 0 or 1..4,
timeout=0..255 (default 1).
SeeAlso: MEM 0040h:0006h,MEM 0040h:007Ch,MEM 0040h:007Dh,MEM 0040h:007Eh
SeeAlso: INT 14/AH=01h
--------K-M00400080--------------------------
MEM 0040h:0080h - KEYBOARD BUFFER START OFFSET FROM SEGMENT 40h (normally 1Eh)
Size: WORD
SeeAlso: MEM 0040h:001Ah,MEM 0040h:001Eh,MEM 0040h:0082h,INT 16/AH=05h
--------K-M00400082--------------------------
MEM 0040h:0082h - KEYBOARD BUFFER END+1 OFFSET FROM SEGMENT 40h (normally 3Eh)
Size: WORD
Note: XT BIOS dated 11/08/82 ends here
SeeAlso: MEM 0040h:001Ch,MEM 0040h:003Eh,MEM 0040h:0080h,INT 16/AH=05h
--------V-M00400084--------------------------
MEM 0040h:0084h - VIDEO (EGA/MCGA/VGA) - ROWS ON SCREEN MINUS ONE
Size: BYTE
SeeAlso: MEM 0040h:0085h,INT 10/AX=1100h
--------V-M00400085--------------------------
MEM 0040h:0085h - VIDEO (EGA/MCGA/VGA) - CHARACTER HEIGHT IN SCAN-LINES
Size: WORD
SeeAlso: MEM 0040h:0084h,INT 10"LIRVGA19"
!!!
--------V-M00400087--------------------------
MEM 0040h:0087h - VIDEO (EGA/VGA) CONTROL: [MCGA: =00h]
Size: BYTE
SeeAlso: MEM 0040h:0084h,MEM 0040h:0085h,MEM 0040h:0088h
Bitfields for EGA/VGA Video control flags:
Bit(s) Description (Table M0024)
7 do not to clear RAM on mode set (see INT 10h, AH=00h)
6-5 RAM on adapter = (this field + 1) * 64K
4 reserved
3 EGA/VGA video system INactive
2 wait for display enable
1 mono monitor
0 alphanumeric cursor emulation DISabled
When enabled, text mode cursor size (INT 10,AH=01h) settings looking
like CGA ones are translated to equivalent EGA/VGA ones.
--------V-M00400088--------------------------
MEM 0040h:0088h - VIDEO (EGA/VGA) SWITCHES: [MCGA: reserved]
Size: BYTE
SeeAlso: MEM 0040h:0087h,MEM 0040h:0089h
Bitfields for EGA/VGA Video switches:
Bit(s) Description (Table M0025)
7-4 power-on state of feature connector bits 3-0
3-0 configuration switches 4-1 (=0 on, =1 off) (see #M0026)
Note: when bit 4 of 0040h:0089h is 0, VGA emulates 350-line EGA if this
byte is x3h or x9h, otherwise emulates 200-line CGA in 400-line
double scan. VGA resets this byte to x9h after the mode set.
See also note for 0040h:0089h.
(Table M0026)
Values for EGA/VGA configuration switches:
00h Pri MDA, Sec EGA+old color display 40 x 25
01h Pri MDA, Sec EGA+old color display 80 x 25
02h Pri MDA, Sec EGA+ECD normal mode (CGA emul)
03h Pri MDA, Sec EGA+ECD enhanced mode
04h Pri CGA 40 x 25, Sec EGA mono display
05h Pri CGA 80 x 25, Sec EGA mono display
06h Pri EGA+old color display 40 x 25, Sec MDA
07h Pri EGA+old color display 80 x 25, Sec MDA
08h Pri EGA+ECD normal mode (CGA emul), Sec MDA
09h Pri EGA+ECD enhanced mode, Sec MDA
0Ah Pri EGA mono display, Sec CGA 40 x 25
0Bh Pri EGA mono display, Sec CGA 80 x 25
SeeAlso: #M0025
--------b-M00400088--------------------------
MEM 0040h:0088h - Olivetti EGA capabilities???
Size: BYTE???
Bitfields for Olivetti EGA capabilities flags:
Bit(s) Description (Table M0130)
7 640x400 mode related???
6 unknown
5 640x400 mode related???
4-0 unknown
Note: To decide if the 640x400 mode is supported by an Olivetti EGA card
(only the Olivetti EGA card 2 supports it), also check that bit 7
and 5 are set.
SeeAlso: C000h:0000h"Olivetti"
--------V-M00400089--------------------------
MEM 0040h:0089h U - VIDEO (MCGA/VGA) - MODE-SET OPTION CONTROL
Size: BYTE
SeeAlso: MEM 0040h:0087h,MEM 0040h:0088h
Bitfields for Video mode-set option control:
Bit(s) Description (Table M0027)
7,4 requested scan lines
0 0 350-line mode requested
0 1 400-line mode at next mode set
1 0 200-line mode requested
1 1 reserved
Note: Apparently VGA BIOS mode set disregards bit 7 and uses
byte 40h:88h to determine 200/350 selection when bit 4
is zero. Presumably bit 7 is a convenience for other
purposes. Bit 7 is reset to zero after the mode set.
6 display switching enabled
5 reserved
4 if set: use 400-line mode at next mode set
if clear: [VGA] emulate EGA at next mode set
[MCGA] emulate CGA, digital monitor, 200 lines, 8x8 text
Note: this bit is set by the video mode set on VGA, unchanged on MCGA
3 default palette loading DISabled at mode set
2 mono display
1 gray scale summing enabled
0 [VGA] =1 if VGA active, =0 if not
[MCGA] reserved, zero
Note: the Tseng ET4000 BIOS v3.00 uses bits 6-4 of 88h and bits 6-5 of 89h
to specify graphics-mode refresh rates as follows
88h/6 640x480: 1 for 72Hz,0 for 60Hz
88h/5+89h/6 800x600: 00 60Hz
01 56Hz
11 72Hz
88h/4+89h/5 1024x768: 00 interlaced
01 60Hz
10 72Hz???
11 70Hz
--------V-M0040008A--------------------------
MEM 0040h:008Ah U - VIDEO (MCGA/VGA) - INDEX INTO DISPLAY COMBINATION CODE TBL
Size: BYTE
SeeAlso: INT 10/AX=1A00h,#M0039
--------*-M0040008B--------------------------
MEM 0040h:008Bh - PC, PCjr, PC/XT 11/8/82, Convertible - RESERVED
Size: 11 BYTEs
--------B-M0040008B--------------------------
MEM 0040h:008Bh - DISKETTE MEDIA CONTROL
Size: BYTE
Bitfields for diskette media control:
Bit(s) Description (Table M0028)
7-6 last data rate set by controller
00=500kbps, 01=300kbps, 10=250kbps, 11=1Mbps
5-4 last diskette drive step rate selected
00=0Ch, 01=0Dh, 10=0Eh, 11=0Ah
3-2 {data rate at start of operation}
1-0 reserved
Note: EHD BIOS sets this byte to 01h and never reads it back
--------B-M0040008C--------------------------
MEM 0040h:008Ch - FIXED DISK - CONTROLLER STATUS [not XT]
Size: BYTE
SeeAlso: MEM 0040h:008Dh,MEM 0040h:008Eh
--------B-M0040008D--------------------------
MEM 0040h:008Dh - FIXED DISK - CONTROLLER ERROR STATUS [not XT]
Size: BYTE
SeeAlso: MEM 0040h:008Ch,MEM 0040h:008Eh
--------B-M0040008E--------------------------
MEM 0040h:008Eh - FIXED DISK - INTERRUPT CONTROL [not XT]
Size: BYTE
Note: cleared to 00h at start of disk operation, set to FFh by IRQ14
handler when hard disk controller completes command
SeeAlso: MEM 0040h:008Ch,MEM 0040h:008Dh,MEM 0040h:008Fh
--------B-M0040008F--------------------------
MEM 0040h:008Fh U - DISKETTE CONTROLLER INFORMATION [not XT]
Size: BYTE
SeeAlso: MEM 0040h:008Ch,MEM 0040h:008Dh,MEM 0040h:008Eh
Bitfields for diskette controller information:
Bit(s) Description (Table M0029)
7 reserved
6 =1 drive 1 determined
5 =1 drive 1 is multi-rate, valid if drive determined
4 =1 drive 1 supports 80 tracks, always valid
3 reserved
2 =1 drive 0 determined
1 =1 drive 0 is multi-rate, valid if drive determined
0 =1 drive 0 supports 80 tracks, always valid
Note: EHD BIOS sets this byte to 01h and never alters it again
--------B-M00400090--------------------------
MEM 0040h:0090h - DISKETTE DRIVE 0 MEDIA STATE
Size: BYTE
SeeAlso: MEM 0040h:0091h
Bitfields for diskette drive media state:
Bit(s) Description (Table M0030)
7-6 data rate
00=500kbps, 01=300kbps, 10=250kbps, 11=1Mbps
5 double stepping required (e.g. 360kB in 1.2MB)
4 media type established
3 drive capable of supporting 4MB media
2-0 on exit from BIOS, contains
000 trying 360kB in 360kB
001 trying 360kB in 1.2MB
010 trying 1.2MB in 1.2MB
011 360kB in 360kB established
100 360kB in 1.2MB established
101 1.2MB in 1.2MB established
110 reserved
111 all other formats/drives
SeeAlso: #M0031,#M0032
--------B-M00400091--------------------------
MEM 0040h:0091h - DISKETTE DRIVE 1 MEDIA STATE
Size: BYTE
SeeAlso: MEM 0040h:0090h,#M0030
--------B-M00400092--------------------------
MEM 0040h:0092h U - DISKETTE DRIVE 0 MEDIA STATE AT START OF OPERATION
Size: BYTE
Note: officially "Drive 2 media state"
SeeAlso: MEM 0040h:0093h"DRIVE 1"
Bitfields for diskette drive 0 media state at start of operation:
Bit(s) Description (Table M0031)
7-3 (see #M0030)
2 multiple data rate capability determined
1 multiple data rate capability
0 =1 if drive has 80 tracks, =0 if 40 tracks
SeeAlso: #M0030,#M0032
--------d-M00400092--------------------------
MEM 0040h:0092h - Olivetti Quaderno - HARD DISK POWERDOWN COUNTDOWN CLOCK TICKS
Size: BYTE
Note: hard disk is turned off when counter reaches zero
--------B-M00400093--------------------------
MEM 0040h:0093h U - DISKETTE DRIVE 1 MEDIA STATE AT START OF OPERATION
Size: BYTE
Note: officially "Drive 3 media state"
SeeAlso: MEM 0040h:0092h"DRIVE 0"
Bitfields for diskette drive 1 media state at start of operation:
Bit(s) Description (Table M0032)
7-3 (see #M0030)
2 multiple data rate capability determined
1 multiple data rate capability
0 =1 if drive has 80 tracks, =0 if 40 tracks
--HP 100LX/200LX--
display control status
0 =1 if DISPCTL -K
1 =1 if DISPCTL -C
--------B-M00400094--------------------------
MEM 0040h:0094h - DISKETTE DRIVE 0 CURRENT TRACK NUMBER
Size: BYTE
SeeAlso: MEM 0040h:0095h
--------B-M00400095--------------------------
MEM 0040h:0095h - DISKETTE DRIVE 1 CURRENT TRACK NUMBER
Size: BYTE
SeeAlso: MEM 0040h:0094h
--------K-M00400096--------------------------
MEM 0040h:0096h - KEYBOARD STATUS BYTE 1
Size: BYTE
SeeAlso: MEM 0040h:0097h,INT 16/AH=11h
Bitfields for keyboard status byte 1:
Bit(s) Description (Table M0033)
7 =1 read-ID in progress
6 =1 last code read was first of two ID codes
5 =1 force Num Lock if read-ID and enhanced keyboard
4 =1 enhanced keyboard installed
3 =1 Right Alt pressed
2 =1 Right Ctrl pressed
1 =1 last code read was E0h
0 =1 last code read was E1h
SeeAlso: #M0034,#M0010
--------K-M00400097--------------------------
MEM 0040h:0097h - KEYBOARD STATUS BYTE 2
Size: BYTE
SeeAlso: MEM 0040h:0096h,INT 16/AH=11h
Bitfields for keyboard status byte 2:
Bit(s) Description (Table M0034)
7 =1 keyboard transmit error flag
6 =1 LED update in progress
5 =1 RESEND received from keyboard
4 =1 ACK received from keyboard
3 reserved, must be zero
2 Caps Lock LED
1 Num Lock LED
0 Scroll Lock LED
SeeAlso: #M0033,#M0010
--------B-M00400098--------------------------
MEM 0040h:0098h - TIMER2 (AT, PS exc Mod 30) - PTR TO USER WAIT-COMPLETE FLAG
Size: DWORD
Note: (see INT 15/AX=8300h)
SeeAlso: MEM 0040h:009Ch,INT 15/AH=83h,INT 15/AH=86h
--------B-M0040009C--------------------------
MEM 0040h:009Ch - TIMER2 (AT, PS exc Mod 30) - USER WAIT COUNT IN MICROSECONDS
Size: DWORD
SeeAlso: MEM 0040h:0098h,MEM 0040h:00A0h,INT 15/AH=83h,INT 15/AH=86h
--------V-M0040009F--------------------------
MEM 0040h:009Fh - HP 100LX/200LX - VIDEO ZOOM MODE
Size: BYTE
(Table M0035)
Values for HP 100LX/200LX video zoom mode:
02h 80x25 mono
03h 80x25 color
80h 64x18 mono
81h 64x18 color
82h 40x25 mono
83h 40x25 color
84h 40x16 mono
85h 40x16 color
SeeAlso: INT 10/AH=D0h
--------B-M004000A0--------------------------
MEM 0040h:00A0h - TIMER2 (AT, PS exc Mod 30) - WAIT ACTIVE FLAG
Size: BYTE
SeeAlso: MEM 0040h:009Ch,INT 15/AH=83h,INT 15/AH=86h
Bitfields for Timer2 wait active flag:
Bit(s) Description (Table M0036)
7 wait time elapsed
6-1 reserved
0 INT 15/AH=86h has occurred
--------N-M004000A1--------------------------
MEM 0040h:00A1h - BIT 5 SET IF LAN SUPPORT PROGRAM INTERRUPT ARBITRATOR PRESENT
Size: BYTE
Note: DEVICE=DXMA0MOD.SYS
--------N-M004000A2--------------------------
MEM 0040h:00A2h - RESERVED FOR NETWORK ADAPTERS
Size: 6 BYTEs
--------d-M004000A4--------------------------
MEM 0040h:00A4h - PS/2 Mod 30 - SAVED FIXED DISK INTERRUPT VECTOR
Size: DWORD
--------V-M004000A8--------------------------
MEM 0040h:00A8h - VIDEO (EGA/MCGA/VGA) - POINTER TO VIDEO SAVE POINTER TABLE
Size: DWORD
SeeAlso: INT 10/AH=1Ch
Format of Video Save Pointer Table [EGA/VGA/MCGA only]:
Offset Size Description (Table M0037)
00h DWORD ptr to Video Parameter Table
04h DWORD ptr to Parameter Dynamic Save Area, else 0 [EGA/VGA only]
08h DWORD ptr to Alphanumeric Character Set Override, else 0
0Ch DWORD ptr to Graphics Character Set Override, else 0
10h DWORD [VGA only] ptr to Secondary Save Pointer Table, must be valid
14h DWORD reserved, zero
18h DWORD reserved, zero
Note: table initially in ROM, copy to RAM to alter, then update 40h:A8h.
Format of Secondary Video Save Pointer Table [VGA only]:
Offset Size Description (Table M0038)
00h WORD Length of this table in bytes, including this word (1Ah)
02h DWORD ptr to Display Combination Code Table, must be valid
06h DWORD ptr to second Alphanumeric Character Set Override, else 0
0Ah DWORD ptr to User Palette Profile Table, else 0
0Eh DWORD reserved, zero
12h DWORD reserved, zero
16h DWORD reserved, zero
Note: table initially in ROM, copy to RAM to alter, then alter Save Ptr Table.
Format of Display Combination Code Table [VGA only]:
Offset Size Description (Table M0039)
00h BYTE Number of entries in the DCC table at offset 04h
01h BYTE Version number
02h BYTE Maximum display type code that can appear in DCC table
03h BYTE reserved
04h 2N BYTEs Each pair of bytes gives a valid display combination, one
display type per byte (see #M0040)
(Table M0040)
Values for Display Combination display type:
00h no display
01h MDA with mono display
02h CGA with color display
03h reserved
04h EGA with color display
05h EGA with mono display
06h Professional Graphics Controller
07h VGA with mono display
08h VGA with color display
09h reserved
0Ah MCGA with digital color display
0Bh MCGA with analog mono display
0Ch MCGA with analog color display
FFh unrecognised video system
SeeAlso: #M0039
Format of Video Parameter Table [EGA, VGA only]:
Offset Size Description (Table M0041)
00h-03h Modes 00h-03h in 200-line CGA emulation mode
04h-0Eh Modes 04h-0Eh
0Fh-10h Modes 0Fh-10h when only 64kB RAM on adapter
11h-12h Modes 0Fh-10h when >64kB RAM on adapter
13h-16h Modes 00h-03h in 350-line mode
17h VGA Modes 00h or 01h in 400-line mode
18h VGA Modes 02h or 03h in 400-line mode
19h VGA Mode 07h in 400-line mode
1Ah-1Ch VGA Modes 11h-13h
Note: An array of 23 [EGA] or 29 [VGA] elements, each element being 64
bytes long. Elements appear in the above order.
Format of Video Parameter Table element [EGA, VGA only]:
Offset Size Description (Table M0042)
00h BYTE Columns on screen (see 40h:4Ah)
01h BYTE Rows on screen minus one (see 40h:84h)
02h BYTE Height of character in scan lines (see 40h:85h)
03h WORD Size of video buffer (see 40h:4Ch)
05h 4 BYTEs Values for Sequencer Registers 1-4
09h BYTE Value for Miscellaneous Output Register
0Ah 25 BYTEs Values for CRTC Registers 00h-18h
23h 20 BYTEs Values for Attribute Controller Registers 00h-13h
37h 9 BYTEs Values for Graphics Controller Registers 00h-08h
Format of Video Parameter Table [MCGA only] {guesswork from inspection}:
Offset Size Description (Table M0043)
- 16 triplet BYTEs of R,G,B DAC info for 16 colors;
- An array of 11 elements, each element being 32 bytes long.
Elements appear in the order:
Modes 00h,01h in 200-line mode for digital displays
Modes 00h,01h in 400-line mode for analog displays
Modes 02h,03h in 200-line mode for digital displays
Modes 02h,03h in 400-line mode for analog displays
Modes 04h,05h in 200-line mode for digital displays
Modes 04h,05h in 400-line mode for analog displays
Mode 06h in 200-line mode for digital displays
Mode 06h in 400-line mode for analog displays
Mode 11h
Mode 13h in 200-line mode for digital displays
Mode 13h in 400-line mode for analog displays
Format of Video Parameter Table element [MCGA only]:
Offset Size Description (Table M0044)
00h BYTE Columns on screen (see 40h:4Ah)
01h BYTE Rows on screen minus one (see 40h:84h)
02h BYTE Height of character in scan lines (see 40h:85h)
03h WORD Size of video buffer (see 40h:4Ch)
05h WORD ??? always zero
07h 21 BYTEs Video data registers 00h-14h to port 3D5h indexed by 3D4h
1Ch BYTE PEL Mask to port 3C6h
1Dh BYTE CGA Mode Control to port 3D8h
1Eh BYTE CGA Border Control to port 3D9h
1Fh BYTE Extended Mode Control to port 3DDh
Format of Video Parameter Dynamic Save Area [EGA, VGA only]:
Offset Size Description (Table M0045)
00h 16 BYTEs Last data written to Attribute Contr. Palette Registers 0-15
10h BYTE Last data written to Attribute Controller Overscan Register
11h-FFh Reserved
Note: Need for table was that EGA registers were write-only.
Note: If default values (from the Video Parameter Table) are
over-ridden at a mode set by the VGA User Palette Profile
Table, then the Dynamic Save Area is updated with the
default values, not the User Profile ones.
Format of Alphanumeric Character Set Override:
Offset Size Description (Table M0046)
00h BYTE Length in bytes of each character in font table
01h BYTE Character generator RAM bank to load, 0=normal
02h WORD Number of characters in font table, normally 256
04h WORD Code of first character in font table, normally 0
06h DWORD ptr to font table
0Ah BYTE Displayable rows (FFh=use maximum calculated value)
0Bh BYTEs Array of mode values to which this font is to pertain
BYTE FFh end of array
Format of Second Alphanumeric Character Set Override:
Offset Size Description (Table M0047)
00h BYTE Length in bytes of each character in font table
01h BYTE Character generator RAM bank to load, normally non-zero
02h BYTE reserved
03h DWORD ptr to font table
07h BYTEs Array of mode values to which this font is to pertain
BYTE FFh end of array
Note: Authorities differ, some say same as first override above, but IBM
says it is as shown above
Format of Graphics Character Set Override:
Offset Size Description (Table M0048)
00h BYTE Number of displayable character rows
01h WORD Length in bytes of each character in font table
03h DWORD ptr to font table
07h BYTEs Array of mode values to which this font is to pertain
BYTE FFh end of array
Format of User Palette Profile Table [VGA only]:
Offset Size Description (Table M0049)
00h BYTE Underlining: 01h=enable in all alphanumeric modes
00h=enable in monochrome alphanumeric modes only
FFh=disable in all alphanumeric modes
01h BYTE reserved
02h WORD reserved
04h WORD Number (0-17) of Attribute Controller registers in table
06h WORD Index (0-16) of first Attribute Controller register in table
08h DWORD ptr to table of Attribute Controller registers to override
Table is an array of BYTEs.
0Ch WORD Number (0-256) of video DAC Color registers in table
0Eh WORD Index (0-255) of first video DAC Color register in table
10h DWORD ptr to table of video DAC Color registers to override
Table is ??? triplets ??? of BYTEs???
14h BYTEs array of mode values to which this profile is to pertain
BYTE FFh end of array
--------*-M004000AC--------------------------
MEM 0040h:00ACh - RESERVED
Size: 4 BYTEs
--------b-M004000B0--------------------------
MEM 0040h:00B0h - Phoenix 386 BIOS 1.10 10a - LOOP COUNT FOR HARD DISK TIMEOUT
Size: BYTE
Desc: number of times a tight software delay loop should be executed to
generate the sub-55ms delays used internally by the BIOS
Note: also used for delaying when beeping due to full keyboard buffer
SeeAlso: MEM 0040h:00ECh"Dell",INT 15/AH=BCh
--------d-M004000B0--------------------------
MEM 0040h:00B0h - PTR TO 3363 OPTICAL DISK DRIVER OR BIOS ENTRY POINT
Size: DWORD
Notes: When 3363 BIOS present, the ASCIZ signature "OPTIC "occurs 3 bytes
beyond this entry point
When 3363 BIOS and 3363 File System Driver present, the ASCIZ signature
"FILE SYSTEM DRIVER" occurs 3 bytes beyond this entry point
--------b-M004000B0--------------------------
MEM 0040h:00B0h - 1988 Phoenix 386 BIOS 1.10 03 - PARAMS FOR TYPE 48 HARD DISK
Size: 16 BYTEs
SeeAlso: INT 41,INT 46,MEM 0040h:00C0h"HARD DISK"
--------*-M004000B4--------------------------
MEM 0040h:00B4h - RESERVED
Size: WORD
--------b-M004000B5--------------------------
MEM 0040h:00B5h - Dell 4xxDE
Size: BYTE
Bitfields for Dell 4xxDE flags:
Bit(s) Description (Table M0050)
2 ??? (related to disk drives)
5 page tables set to allow Weitek addressing in real mode
6 Weitek math coprocessor present
--------b-M004000B5--------------------------
MEM 0040h:00B5h - Tandy BIOS DATA FLAGS
Size: BYTE
SeeAlso: MEM F000h:C000h
Bitfields for Tandy BIOS data flags:
Bit(s) Description (Table M0131)
0 set if drive A: is 720 Kb
1 set if drive B: is 720 Kb
2-7 unknown
Note: Before checking these bits, the Tandy ROM BIOS ID byte at F000h:C000h
should be verified to be equal to 21h.
---------------------------------------------
MEM 0040h:00E5h - Gigabyte AWARD v4.51PG - ASSOC DRIVE NUMS TO PHYS INTERFACES
Size: BYTE
SeeAlso: MEM 0040h:00E5h"AWARD"
Bitfields for drive number/interface mapping:
Bit(s) Description (Table M0129)
7-6 interface for drive 83h (F:)
00 primary master
01 primary slave
10 secondary master
11 secondary slave
5-4 interface for drive 82h (as for bits 7-6)
3-2 interface for drive 81h (as for bits 7-6)
1-0 interface for drive 80h (C:) (as for bits 7-6)
SeeAlso: #M0128
----------M004000B6--------------------------
MEM 0040h:00B6h - RESERVED FOR POST???
Size: 3 BYTEs
----------M004000B9--------------------------
MEM 0040h:00B9h - ???
Size: 7 BYTEs
--------b-M004000BC--------------------------
MEM 0040h:00BCh - 1993 Phoenix 486 BIOS 1.03 PCI - CPU TYPE/MASK REVISION
Size: WORD
Desc: the high byte contains the CPU type, the low byte the mask revision
(stepping level), as reported to the BIOS in DX by the CPU at startup
SeeAlso: INT 15/AH=C9h
--------b-M004000C0--------------------------
MEM 0040h:00C0h - 1988 Phoenix 386 BIOS 1.10 03 - PARAMS FOR TYPE 49 HARD DISK
Size: 16 BYTEs
SeeAlso: INT 41,INT 46,MEM 0040h:00B0h"HARD DISK"
--------*-M004000C0--------------------------
MEM 0040h:00C0h - RESERVED
Size: 14 BYTEs
--------K-M004000C2--------------------------
MEM 0040h:00C2h - AMI BIOS 1.00.12.AX1T - KEYBOARD TYPE
Size: WORD
Desc: this word contains an indication of the type of keyboard
(controller???) attached to the system
Note: AMI's APM code checks for 4147h vs. other value (5047h seen on Intel
"Plato" motherboard)
SeeAlso: #00586,INT 16/AH=F2h
--------b-M004000CE--------------------------
MEM 0040h:00CEh - COUNT OF DAYS SINCE LAST BOOT
Size: WORD
--------*-M004000D0--------------------------
MEM 0040h:00D0h - RESERVED
Size: 32 BYTEs
--------S-M004000D0--------------------------
MEM 0040h:00D0h - Digiboard MV/4 - LENGTH OF DATA TABLE
Size: BYTE
--------d-M004000D0--------------------------
MEM 0040h:00D0h EHD floppy - INSTALLATION FLAGS
Size: BYTE
Bitfields for EHD floppy installation flags:
Bit(s) Description (Table M0051)
4 installation completed
3-0 drives 0-3
--------b-M004000D0--------------------------
MEM 0040h:00D0h - AMI BIOS v1.00.12.AX1T - EPP - SCRATCH SPACE
Size: WORD
Desc: this word holds the value of BX during an EPP BIOS call
SeeAlso: MEM 0040h:00D2h"AMI",MEM 0040h:00D5h"AMI",MEM 0040h:00D6h"AMI"
SeeAlso: MEM 0040h:00DDh"AMI"
--------S-M004000D1--------------------------
MEM 0040h:00D1h - Digiboard MV/4 - PRODUCT ID
Size: BYTE
--------S-M004000D2--------------------------
MEM 0040h:00D2h - Digiboard MV/4 - BASE ADDRESS FOUND
Size: WORD
--------b-M004000D2--------------------------
MEM 0040h:00D2h - AMI BIOS v1.00.12.AX1T - EPP BASE I/O PORT
Size: WORD
--------S-M004000D4--------------------------
MEM 0040h:00D4h - Digiboard MV/4 - PORTS
Size: BYTE
--------S-M004000D5--------------------------
MEM 0040h:00D5h - Digiboard MV/4 - IRQ
Size: BYTE
--------d-M004000D5--------------------------
MEM 0040h:00D5h - EHD floppy - NUMBER OF FLOPPY DISK CONTROLLERS IN SYSTEM
Size: BYTE
--------b-M004000D5--------------------------
MEM 0040h:00D5h - AMI BIOS v1.00.12.AX1T - EPP - PARALLEL PORT 0 CAPABILITIES
Size: BYTE
SeeAlso: MEM 0040h:00D2h"AMI",MEM 0040h:00D6h"AMI",MEM 0040h:00D7h"AMI"
SeeAlso: MEM 0040h:00DCh"AMI"
--------d-M004000D6--------------------------
MEM 0040h:00D6h - EHD floppy - AND-BITS TO ADJUST PORT ADDRESS
Size: BYTE
Note: this byte contains FFh if controller at 03Fxh and 7Fh if at 037xh; the
value is ANDed with DL prior to using IN A?,DX or OUT DX,A?
instructions
--------K-M004000D6--------------------------
MEM 0040h:00D6h - Digiboard MV/4 - NUMBER OF KEYBOARDS FOUND
Size: WORD
SeeAlso: MEM 0040h:00D8h"Digiboard"
--------b-M004000D6--------------------------
MEM 0040h:00D6h - AMI BIOS v1.00.12.AX1T - EPP - PARALLEL PORT 0 IRQ
Size: BYTE
SeeAlso: MEM 0040h:00D2h"AMI",MEM 0040h:00D5h"AMI",MEM 0040h:00D8h"AMI"
SeeAlso: MEM 0040h:00DDh"AMI"
--------d-M004000D7--------------------------
MEM 0040h:00D7h - EHD floppy - DRIVE 0 DISKETTE MEDIA STATE
Size: BYTE
Note: the value in this byte is copied into 0040h:0090h (diskette 0 status)
SeeAlso: MEM 0040h:00D8h"EHD",MEM 0040h:00D9h"EHD",MEM 0040h:00DAh"EHD"
Bitfields for EHD diskette media state:
Bit(s) Description (Table M0052)
7-6 data rate: 00=500kbps,01=300kbps,10=250k,11=1M/S
5 double stepping required (e.g. 360kB in 1.2MB)
4 media type established
3 reserved
2-0 on exit from BIOS, contains:
000 trying 360kB in 360kB
001 trying 360kB in 1.2MB
010 trying 1.2MB in 1.2MB
011 360kB in 360kB established
100 360kB in 1.2MB established
101 1.2MB in 1.2MB established
110 reserved (2M8?)
111 all other formats/drives
--------b-M004000D7--------------------------
MEM 0040h:00D7h - AMI BIOS v1.00.12.AX1T - EPP - PARALLEL PORT 1 CAPABILITIES
Size: BYTE
SeeAlso: MEM 0040h:00D2h"AMI",MEM 0040h:00D5h"AMI",MEM 0040h:00D6h"AMI"
SeeAlso: MEM 0040h:00DDh"AMI"
--------M-M004000D8--------------------------
MEM 0040h:00D8h - Digiboard MV/4 - NUMBER OF MICE FOUND
Size: WORD
SeeAlso: MEM 0040h:00D6h"Digiboard",MEM 0040h:00DAh"Digiboard"
--------d-M004000D8--------------------------
MEM 0040h:00D8h - EHD floppy - DRIVE 1 DISKETTE MEDIA STATE
Size: BYTE
SeeAlso: MEM 0040h:00D7h"EHD",MEM 0040h:00D9h"EHD",MEM 0040h:00DAh"EHD"
--------b-M004000D8--------------------------
MEM 0040h:00D8h - AMI BIOS v1.00.12.AX1T - EPP - PARALLEL PORT 1 IRQ
Size: BYTE
SeeAlso: MEM 0040h:00D2h"AMI",MEM 0040h:00D6h"AMI",MEM 0040h:00D7h"AMI"
SeeAlso: MEM 0040h:00DDh"AMI"
--------b-M004000D8--------------------------
MEM 0040h:00D8h U - Phoenix BIOS 4.0 Rel 6.0 - POWER MANAGEMENT FLAGS
Size: BYTE
SeeAlso: INT 15/AX=5300h
--------d-M004000D9--------------------------
MEM 0040h:00D9h - EHD floppy - DRIVE 2 DISKETTE MEDIA STATE
Size: BYTE
SeeAlso: MEM 0040h:00D7h"EHD",MEM 0040h:00D8h"EHD",MEM 0040h:00DAh"EHD"
--------S-M004000DA--------------------------
MEM 0040h:00DAh - Digiboard MV/4 - CURRENT PORT (used by VGA initializatn only)
Size: BYTE
SeeAlso: MEM 0040h:00D8h"Digiboard"
--------d-M004000DA--------------------------
MEM 0040h:00DAh - EHD floppy - DRIVE 3 DISKETTE MEDIA STATE
Size: BYTE
SeeAlso: MEM 0040h:00D7h"EHD",MEM 0040h:00D8h"EHD",MEM 0040h:00D9h"EHD"
--------S-M004000DB--------------------------
MEM 0040h:00DBh - Digiboard MV/4 - MASTER 8259 MASK (used by VGA init only)
Size: BYTE
SeeAlso: MEM 0040h:00DCh"Digiboard"
--------d-M004000DB--------------------------
MEM 0040h:00DBh - EHD floppy - DRIVE 0 NEEDS RECALIBARATION
Size: BYTE
SeeAlso: MEM 0040h:00DCh"EHD",MEM 0040h:00DDh"EHD",MEM 0040h:00DEh"EHD"
--------S-M004000DC--------------------------
MEM 0040h:00DCh - Digiboard MV/4 - SLAVE 8259 MASK (used by VGA init only)
Size: BYTE
SeeAlso: MEM 0040h:00DBh"Digiboard"
--------b-M004000DC--------------------------
MEM 0040h:00DCh - AMI BIOS v1.00.12.AX1T - EPP - PARALLEL PORT 0 MODE
Size: BYTE
SeeAlso: MEM 0040h:00D2h"AMI",MEM 0040h:00D5h"AMI",MEM 0040h:00DDh"AMI"
SeeAlso: INT 17/AX=0200h/BX=5050h
(Table M0053)
Values for AMI Enhanced Parallel Port mode:
01h compatibility mode
02h bi-directional mode
04h EPP mode
SeeAlso: #00637
--------d-M004000DC--------------------------
MEM 0040h:00DCh - EHD floppy - DRIVE 1 NEEDS RECALIBARATION
Size: BYTE
SeeAlso: MEM 0040h:00DBh"EHD",MEM 0040h:00DDh"EHD",MEM 0040h:00DEh"EHD"
--------b-M004000DC--------------------------
MEM 0040h:00DCh - AMI BIOS v1.00.12.AX1T - EPP - PARALLEL PORT 1 MODE
Size: BYTE
SeeAlso: MEM 0040h:00D2h"AMI",MEM 0040h:00DCh"AMI",#M0053
--------d-M004000DD--------------------------
MEM 0040h:00DDh - EHD floppy - DRIVE 2 NEEDS RECALIBARATION
Size: BYTE
SeeAlso: MEM 0040h:00DBh"EHD",MEM 0040h:00DCh"EHD",MEM 0040h:00DEh"EHD"
--------d-M004000DE--------------------------
MEM 0040h:00DEh - EHD floppy - DRIVE 3 NEEDS RECALIBARATION
Size: BYTE
SeeAlso: MEM 0040h:00DBh"EHD",MEM 0040h:00DCh"EHD",MEM 0040h:00DDh"EHD"
--------b-M004000DF--------------------------
MEM 0040h:00DFh - AMI BIOS v1.00.12.AX1T - EPP - PARALLEL PORT LOCK STATE
Size: BYTE
Note: set to 01h if last request was to lock a port, 00h if last request was
to unlock a port
SeeAlso: MEM 0040h:00D2h"AMI",MEM 0040h:00DCh"AMI"
--------b-M004000E0--------------------------
MEM 0040h:00E0h - AMI BIOS v1.00.12.AX1T - EPP - REAL-TIME DEVICE COUNT
Size: BYTE
Desc: contains the number of advertised real-time devices as set by EPP
function 12h (see #00632)
SeeAlso: MEM 0040h:00D2h"AMI",MEM 0040h:00DFh"AMI"
--------b-M004000E0--------------------------
MEM 0040h:00E0h - Phoenix 386 BIOS - DRIVE PARAMETER TABLE FOR FIRST HARD DISK
Size: 16 BYTEs
Note: this area is used to store the driver parameter table for the first
hard disk if it has been setup as the user-configurable "type 47"
--------d-M004000E3--------------------------
MEM 0040h:00E3h - EHD floppy - DRIVE 0 DISKETTE TYPE (from jumpers)
Size: BYTE
SeeAlso: MEM 0040h:00E4h,MEM 0040h:00E5h"EHD",MEM 0040h:00E6h"EHD"
(Table M0054)
Values for EHD floppy diskette type:
01h undefined by diskette change (360K)
02h 1.2M
03h 720K
04h 1.44M
05h 2.88M
--------d-M004000E4--------------------------
MEM 0040h:00E4h - EHD floppy - DRIVE 1 DISKETTE TYPE (from jumpers)
Size: BYTE
SeeAlso: MEM 0040h:00E3h,MEM 0040h:00E5h"EHD",MEM 0040h:00E6h"EHD"
--------d-M004000E5--------------------------
MEM 0040h:00E5h - EHD floppy - DRIVE 2 DISKETTE TYPE (from jumpers)
Size: BYTE
SeeAlso: MEM 0040h:00E3h,MEM 0040h:00E4h"EHD",MEM 0040h:00E6h"EHD"
---------------------------------------------
MEM 0040h:00E5h - AWARD v4.51PG - ASSOC DRIVE NUMBERS TO PHYSICAL INTERFACES
Size: BYTE
SeeAlso: MEM 0040h:00B5h"Gigabyte"
Bitfields for drive number/interface mapping:
Bit(s) Description (Table M0128)
7-6 interface for drive 83h (F:)
00 primary master
01 primary slave
10 secondary master
11 secondary slave
5-4 interface for drive 82h (as for bits 7-6)
3-2 interface for drive 81h (as for bits 7-6)
1-0 interface for drive 80h (C:) (as for bits 7-6)
SeeAlso: #M0129
--------d-M004000E6--------------------------
MEM 0040h:00E6h - EHD floppy - DRIVE 3 DISKETTE TYPE (from jumpers)
Size: BYTE
SeeAlso: MEM 0040h:00E3h,MEM 0040h:00E4h"EHD",MEM 0040h:00E5h"EHD"
--------d-M004000EA--------------------------
MEM 0040h:00EAh - Omti controller - SEGMENT OF EXTENDED BIOS DATA AREA???
Size: WORD
Note: drive parameter tables stored in specified segment
--------b-M004000EC--------------------------
MEM 0040h:00ECh - Dell 4xxDE BIOS A11 - LOOP COUNT FOR DELAYS
Size: WORD
----------M004000F0--------------------------
MEM 0040h:00F0h - INTRA-APPLICATION COMMUNICATION AREA
Size: 16 BYTEs
--------B-M00500000--------------------------
MEM 0050h:0000h - PRINT-SCREEN STATUS
Size: BYTE
--------J-M00500001--------------------------
MEM 0050h:0001h - NEC PC-9800 series - SCREEN MODE
Size: BYTE
Note: if bit 3 set, the screen is in high-resolution mode (start memory at
segment E000h instead of A000h)
--------D-M00500004--------------------------
MEM 0050h:0004h - MS-DOS - LOGICAL DRIVE FOR SINGLE-FLOPPY SYSTEM (A: / B:)
Size: BYTE
--------A-M0050000E--------------------------
MEM 0050h:000Eh - STATE OF BREAK CHECKING AT START OF BASICA.COM EXECUTION
Size: BYTE
--------A-M0050000F--------------------------
MEM 0050h:000Fh - BASICA VERSION FLAG
Size: BYTE
Note: this byte contains the value 02h if BASICA v2.10 is running
--------A-M00500010--------------------------
MEM 0050h:0010h - POINTER TO BASIC DATA SEGMENT
Size: WORD
--------A-M00500012--------------------------
MEM 0050h:0012h - INT 08 VECTOR AT START OF BASICA.COM EXECUTION
Size: DWORD
--------A-M00500016--------------------------
MEM 0050h:0016h - INT 1B VECTOR AT START OF BASICA.COM EXECUTION
Size: DWORD
--------A-M0050001A--------------------------
MEM 0050h:001Ah - INT 24 VECTOR AT START OF BASICA.COM EXECUTION
Size: DWORD
--------D-M00600000--------------------------
MEM 0060h:0000h - DOS 2+ SCRATCH SPACE
Size: 256 BYTEs
Note: used during DOS 2+ boot process
--------D-M00600000--------------------------
MEM 0060h:0000h - DOS 1.x IO.SYS LOAD ADDRESS
--------D-M00700000--------------------------
MEM 0070h:0000h - DOS 2+ IO.SYS LOAD ADDRESS
--------D-M00700100--------------------------
MEM 0070h:0100h - DOS 5+ - ORIGINAL INTERRUPT VECTORS 10h,13h,15h,19h,1Bh
Size: 25 BYTEs
Note: each value is stored as a BYTE for the interrupt number followed by
a DWORD for the vector
these values are restored on INT 19 by recent versions of
DR/Novell/PC/MS-DOS (MS-DOS 3.x used this area to support HIMEM.SYS)
not supported by OS/2 MDOS
SeeAlso: MEM 0080h:0000h,INT 2F/AH=13
--------d-M0070016C--------------------------
MEM 0070h:016Ch - DR-DOS 7.02-7.03 - "DEVNO" AUX/PRN PORT ASSIGNMENTS
Size: 2 BYTEs
016Ch BYTE PRN: assignment (0..2 for LPT1:..LPT3: (3 for LPT4:); default: 1)
016Dh BYTE AUX: assignment (0..3 for COM1:..COM4:; default: 1)
Notes: As long as the built-in AUX: or PRN: drivers are in effect, these
settings can be transparently reassigned at the DR-OpenDOS 7.02 /
DR-DOS 7.03 DOS BIOS device driver level (that is below DOS
redirection etc., but above ROM BIOS) using the undocumented
CONFIG.SYS AUX=0|1..4 and PRN=0|1..3|4 directive, where 1..4
specifies COM1:..COM4: or LPT1:..LPT4: and the high speed bypass 0
selects the previous hardwired equivalence of AUX: with COM1: and
PRN: with LPT1: at this level, saving a few clock cycles. The system
defaults to AUX=1 and PRN=1 (that is 0 in the internal variables).
If the high speed bypass was not enabled, the assigment can be changed
anytime later by updating these bytes, e.g. by a future issue of the
MODE utility. If the highspeed bypass has been enabled, changes have
no effect.
The LPT4 setting (or corresponding value 3) is valid for
DR-OpenDOS 7.02 and DR-DOS 7.02, but due to a bug introduced with the
partial removal of the LPT4: device, it must not be used under
DR-DOS 7.03.
The address 0070h:016Ch is only valid for DR-OpenDOS 7.02 up to
DR-DOS 7.03 (BDOS 73h), and will most probably change with future
releases of DR-DOS!
These bytes are local for each task running.
SeeAlso: INT 21h/03h, INT 21h/04h, INT 21h/05h, MEM 0040h:0000h etc.
--------H-M00800000--------------------------
MEM 0080h:0000h - 80286 CPU - LOADALL WORKSPACE
Size: 102 BYTEs
Desc: on the 80286 (unlike 80386), the state buffer from which the LOADALL
instruction loads all internal registers is hardwired to physical
address 000800h
Note: several versions 3.x of MS-DOS leave an empty space at offset 100h in
IO.SYS (which is loaded at 0070h:0000h) so that HIMEM.SYS can use
LOADALL on 80286 machines without having to save/restore the area
of memory that LOADALL uses
SeeAlso: MEM 0070h:0100h
--------m-m80C00000--------------------------
MEM 80C00000h - Compaq Deskpro 386 system memory board register
Size: BYTE
80C00000 R Diagnostics register (see #M0055)
80C00000 W RAM relocation register (see #M0056)
Bitfields for Compaq Deskpro 386 diagnostics register:
Bit(s) Description (Table M0055)
7 =0 memory expansion board is installed
6 =0 second 1 MB of system memory board is installed
5-4 base memory
00 set to 640 KB
01 invalid
10 set to 512 KB
11 set to 256 KB
3 parity correct in byte 3
2 parity correct in byte 2
1 parity correct in byte 1
0 parity correct in byte 0 (in 32-bit double word)
SeeAlso: #M0056
Bitfields for Compaq Deskpro 386 RAM relocation register:
Bit(s) Description (Table M0056)
7-2 reserved, always write 1's.
1 =0 Write-protect 128-Kbyte RAM at FE0000.
=1 Do not write-protect RAM at FE0000.
0 =0 Relocate 128-Kbyte block at FE0000 to address 0E0000
=1 128-Kbyte RAM is addressed only at FE0000.
SeeAlso: #M0055
----------m80C00000--------------------------
MEM 80C00000h - COMPAQ DIAGNOSTICS REGISTER
Size: WORD
Note: Writing to F000h:FFE0h seems to involve unlocking the memory by writing
FEFEh to this address first. The write-protection can be
reestablished by writing FCFCh to this address??? This was seen done
by MS HIMEM.SYS.
SeeAlso: F000h:FFE0h
Bitfields for Compaq Diagnostics Register:
Bit(s) Description (Table M0132)
15-10 unknown purpose (should remain set???)
9 =1 memory is read-write???
=0 memory is read-only???
8 =1 to disable ROM replacement???
=0 normal???
7-2 unknown purpose (should remain set???)
1 =1 memory is read-write
=0 memory is read-only
0 =1 to disable ROM replacement???
=0 normal
Note: Writing to F000h:FFE0h seems to involve unlocking the memory by writing
FEFEh to this address first. The write-protection can be
reestablished by writing FCFCh to this address???
Microsoft HIMEM.SYS was seen to do this.
SeeAlso: F000h:FFE0h
--------V-MA0000000--------------------------
MEM A000h:0000h - EGA+ GRAPHICS BUFFER
Size: 65536 BYTEs
--------V-MA0000000--------------------------
MEM A000h:0000h - S3 - MEMORY-MAPPED GRAPHICS PROCESSOR REGISTERS
Size: 65536 BYTEs
Note: the S3 graphics processor registers can be mapped at either
linear 000A0000h or at offset 16M from the start of the linear
frame buffer
--------V-MA0001234--------------------------
MEM A000h:1234h - S3 - MEMORY-MAPPED ???
Size: WORD???
Note: the Win95 driver for the Stealth64 tests various bits in this word,
sometimes looping until a particular bit is set or cleared
--------V-MA0008000--------------------------
MEM A000h:8000h - S3 - MEMORY-MAPPED PCI CONFIGURATION REGISTERS
Size: 256 BYTEs
Notes: the S3 graphics processor registers can be mapped at either
linear 000A0000h or at offset 16M from the start of the linear
frame buffer
additional setup may be required to access these registers via memory
the DWORDs at 8080h,8088h,808Ch,8090h,8094h,8098h,809Ch are used by
STLTH64.DRV
the DWORDs at 18080h,18088h,18090h,18094h,18098h,1809Ch are written
by S3_32.DLL
--------V-MA0008100--------------------------
MEM A000h:8100h - S3 - MEMORY-MAPPED PACKED REGISTERS
Size: 80 BYTEs
Access: Write-Only
Desc: these registers pack two 16-bit I/O registers into a single DWORD
for faster writes
Note: the S3 graphics processor registers can be mapped at either
linear 000A0000h or at offset 16M from the start of the linear
frame buffer
SeeAlso: MEM A000h:8180h
Format of S3 Trio32/Trio64 packed memory-mapped registers:
Offset Size Description (Table M0057)
8100h DWORD drawing control: row (low word), column (high word)
"CUR_X" and "CUR_Y" (see PORT 82E8h,PORT 86E8h)
8104h DWORD (Trio64) drawing control: row 2 (low word), column 2 (high word)
8108h DWORD drawing control: destination Y and axial step constant (low
word), destination X and axial step constant (high word)
(see PORT 8AE8h,PORT 8EE8h)
810Ch DWORD (Trio64 only) destination Y 2 and axial step constant 2 (low
word), destination X 2 and axial step constant 2 (high word)
(see PORT 8AEAh,PORT 8EEAh)
8110h WORD error term (see PORT 92E8h)
8112h WORD (Trio64) error term 2 (see PORT 92EAh)
8114h DWORD unused??? (would correspond to PORT 96E8h)
8118h WORD drawing control: command register (see PORT 9AE8h)
811Ah WORD (Trio64) command register 2 (see PORT 9AEAh)
811Ch DWORD short stroke (see PORT 9EE8h)
8120h DWORD background color (see PORT A2E8h)
8124h DWORD foreground color (see PORT A6E8h)
8128h DWORD write mask (see PORT AAE8h)
812Ch DWORD read mask (see PORT AEE8h)
8130h DWORD color compare (see PORT B2E8h)
8134h DWORD background mix (low word) and foreground mix (high word)
(see PORT B6E8h,PORT BAE8h)
8138h DWORD top scissors (low word) and left scissors (high word)
(see PORT BEE8h,#P1047)
813Ch DWORD bottom scissors (low word) and right scissors (high word)
(see PORT BEE8h,#P1047)
8140h DWORD data manipulation control (low word) and miscellaneous 2 (high
word) (see PORT BEE8h,#P1047)
8144h DWORD miscellaneous (low word) and read register select (high word)
(see PORT BEE8h,#P1047)
8148h DWORD minor axis pixel count (low word) and major axis pixel count
(high word) (see PORT BEE8h,#P1047,PORT 96E8h)
814Ch WORD (Trio64) major axis pixel count 2 (see PORT 96EAh)
8150h DWORD pixel data transfer (see PORT E2E8h,PORT E2EAh)
8154h 4 DWORDs ???
8164h DWORD ??? (written by STLTH64.DRV for Win95)
8168h DWORD (Trio64 only) Pattern Y (low word), Pattern X (high word)
(see PORT EAE8h,PORT EAEAh)
816Ch DWORD ??? (written by STLTH64.DRV for Win95)
Note: setting 8138h to 0 and 813Ch to 12345678h may be a magic value to unlock
some S3 features
SeeAlso: #M0073,#M0070
--------V-MA0008180--------------------------
MEM A000h:8180h - S3 - STREAMS PROCESSOR
Size: 128 BYTEs
Note: the S3 graphics processor registers can be mapped at either
linear 000A0000h or at offset 16M from the start of the linear
frame buffer
SeeAlso: MEM A000h:8100h,MEM A000h:FF00h
Format of S3 Streams Processor memory-mapped registers:
Offset Size Description (Table M0058)
8180h DWORD primary stream control (see #M0059)
8184h DWORD chroma key control (see #M0063)
8188h DWORD unused??? (high word seems to echo 8184h, low word 8180h)
818Ch DWORD unused??? (high word seems to echo 8184h, low word 8180h)
8190h DWORD secondary stream control (see #M0061)
8194h DWORD chroma key upper bound (bits 23-0) (see also #M0063)
8198h DWORD secondary stream stretch (see #M0062)
819Ch DWORD ??? (set by S3_32.DLL)
bits 30-16: ???
bits 14-0: ???
81A0h DWORD blend control (see #M0064)
81A4h 3 DWORDs unused??? (reads as FFFFFFFFh)
81B0h 4 DWORDs ??? (appear to be read-only)
81C0h DWORD primary frame buffer address 0 (bits 21-0, multiple of 8)
81C4h DWORD primary frame buffer address 1 (bits 21-0, multiple of 8)
81C8h DWORD primary stream stride (bits 11-0 only)
81CCh DWORD double buffer/LPB control (see #M0065)
81D0h DWORD secondary frame buffer address 0 (bits 21-0, multiple of 8)
81D4h DWORD secondary frame buffer address 1 (bits 21-0, multiple of 8)
81D8h DWORD secondary stream stride (bits 11-0 only)
81DCh DWORD opaque overlay control (see #M0066)
81E0h DWORD K1 -- vertical stretch (lines in) (bits 10-0 only)
set to one less than # lines in
81E4h DWORD K2 -- vertical stretch (stretch factor) (bits 10-0 only)
set to -(#lines_in - #lines_out)
81E8h DWORD DDA vertical accumulator (bits 11-0 only) (lines out)
set to (#lines_out) - 1
81ECh DWORD streams FIFO and RAS control (see #M0067)
81F0h DWORD primary start coordinate (see #M0068)
81F4h DWORD primary window size (see #M0069)
81F8h DWORD secondary start coordinate (see #M0068)
81FCh DWORD secondary window size (see #M0069)
Note: changes to registers 81E0h-81E8h do not take effect until the next
VSYNC
SeeAlso: #M0073,#M0057,#M0070
Bitfields for S3 Streams Processor primary stream control:
Bit(s) Description (Table M0059)
31 reserved
30-28 filter characteristics
000 unchanged primary stream
001 2X stretch by replicating pixels
010 2X stretch by interpolating horizontally (replicating vertically)
else reserved
27 reserved
26-24 color mode (see #M0060)
23-0 officially reserved, but writing nonzero values can hang display
Notes: the primary stream is the output from the display RAM
bits 26-24 correspond to CR67 color mode field (see #P0688)
SeeAlso: #M0058,#M0061
(Table M0060)
Values for S3 Streams Processor color mode:
000b eight bits per pixel
001b YCrCb 4:2:2 unsigned, range 10h-F0h (secondary stream only)
010b YUV 4:2:2, range 00h-FFh (secondary stream only)
011b keyed high-color (1-5-5-5)
100b YUV 2:1:1 two's complement (secondary stream only)
101b high-color (5-6-5)
110b reserved
111b true-color (32bpp, high byte ignored)
SeeAlso: #M0059,#M0061
Bitfields for S3 Streams Processor secondary stream control:
Bit(s) Description (Table M0061)
31 reserved
30-28 filter characteristics
000 unchanged secondary stream
001 linear 0-2-4-2-0 for 1x-2x stretch
010 bi-linear for 2x-4x stretch
011 linear 1-2-2-2-1 for 4x+ stretch
else reserved
28 enable smoothing between horizontally adjacent bits (trial-and-error)
27 reserved
26-24 color mode (see #M0060,#M0074)
23-12 reserved
11-0 initial value of DDA horizontal accumulator
set to 2*(inwidth-1)-(outwidth-1)
Notes: the secondary stream is typically live video, but can be pointed at
any part of video memory
changes to this register do not take effect until the next VSYNC
SeeAlso: #M0058,#M0059,#M0062
Bitfields for S3 Streams Processor stretch/filter constants:
Bit(s) Description (Table M0062)
31-27 reserved
26-16 K2 horizontal scaling factor (input width - output width)
15-11 reserved
10-0 K1 horizontal scaling factor (input width - 1)
Note: changes to this register do not take effect until the next VSYNC
SeeAlso: #M0061
Bitfields for S3 Streams Processor chroma-key control:
Bit(s) Description (Table M0063)
31-29 reserved
28 key control
=1 normal color-key or chroma-key
=0 (keyed RGB 1-5-5-5 mode only) extract key from high bit of input
stream; if key bit is clear, show pixel from other stream
27 reserved
26-24 color comparison precision
000 compare bit 7 of R,G, and B values only
001 compare bits 7-6
...
111 compare bits 7-0
23-0 chroma-key color value
23-16 = red or Y
15-8 = green or U/Cb
7-0 = blue or V/Cr
Note: if the keyed stream is YUV or YCrCb, then this register contains the
lower bound and 8194h contains the upper bound of the chromakey
value
SeeAlso: #M0058
Bitfields for S3 Streams Processor blend control:
Bit(s) Description (Table M0064)
31-27 reserved (unused)
26-24 blend type
000 show secondary stream (video) overlaying primary stream
001 show primary stream overlaying secondary stream
010 blend pri/sec. streams (dissolve, secondary intensity = full-prim.)
011 blend pri/sec. streams
100 reserved (blank display)
101 show secondary stream only where chroma-key color present
110 show secondary stream (video) unconditionally
111 reserved (blank display)
23-14 reserved
13 ??? (officially reserved, but set by S3_32.DLL)
12-8 primary stream intensity (00h-1Ch, must be multiple of 4)
4-0 secondary stream intensity (00h-1Ch, must be multiple of 4)
(ignored for blend type 010)
Notes: for blend type 011, the primary and secondary stream intensities should
not total more than 20h to avoid wraparounds which appear as
incorrect colors; for blend type 010, the secondary stream intensity
is automatically computed as 20h - bits12-8
changes to this register do not take effect until the next VSYNC
SeeAlso: #M0058
Bitfields for S3 Streams Processor double-buffer/LPB control:
Bit(s) Description (Table M0065)
31-7 reserved (unused; all but bit 7 appear to be read-only, as well)
6 LPB frame buffer auto-toggle
if set, End-of-Frame toggles bit 4
5 delay loading LPB input buffer select until next End-of-Frame
4 LPB input buffer select (see #M0073)
0 use LPB frame buffer address 0 (FF0Ch) for incoming video data
1 use LPB frame buffer address 1 (FF10h)
3 reserved
2-1 secondary stream buffer select
00 use frame buffer address 0 (81D0h)
01 use frame buffer address 1 (81D4h)
1x use frame buffer 0/1 (81D0h/81D4h) selected by bit 4 for secondary
stream and selected LPB frame buffer for LPB input
0 primary stream buffer select
=0 use frame buffer address 0 (81C0h)
=1 use frame buffer address 1 (81C4h)
SeeAlso: #M0058,#M0073
Bitfields for S3 Streams Processor opaque overlay control:
Bit(s) Description (Table M0066)
31 enable opaque overlay control
30 select top stream (0 = secondary on top, 1 = primary)
29 reserved
28-19 pixel resume fetch
number of quadwords from background's left edge to position at which
to start fetching pixels again
18-13 reserved
12-3 pixel stop fetch
number of quadwords from background's left edge to position at which
to stop fetching pixels
2-0 reserved
SeeAlso: #M0058
Bitfields for S3 Streams Processor streams FIFO and RAS control register:
Bit(s) Description (Table M0067)
31-22 reserved (0)
21 skip 0.5 MCLK delay of PD[63:0] output (default = 0)
20 skip memory arbitration for ROM cycles (default = 0)
19 do not tristate PD[63:16] during ROM cycles (default = 0)
(set by Win95 driver when using ISA bus)
18 EDO wait state control (LPB memory cycles only)
=0 two-cycle accesses
=1 one-cycle EDO accesses
17 reserved
16 RAS# pre-charge control
=0 use CR68(bit3) setting (2.5/3.5 MCLKs)
=1 1.5 MCLKs
15 RAS# low control
=0 use CR68(bit2) setting (3.5/4.5 MCLKs)
=1 2.5 MCLKs
14-10 primary stream FIFO threshold
number of filled quadword slots at which to request refilling
9-5 secondary stream FIFO threshold
number of filled quadword slots at which to request refilling
4-0 FIFO allocation, in quadword slots
00000 primary stream = 24, secondary = 0
01000 primary stream = 16, secondary = 8
01100 primary stream = 12, secondary = 12
10000 primary stream = 8, secondary = 16
11000 primary stream = 0, secondary = 24
else reserved
SeeAlso: #M0058
Bitfields for S3 Streams Processor start coordinate:
Bit(s) Description (Table M0068)
31-27 reserved (read-only)
26-16 X coordinate (column) of upper left corner, plus 1
15-11 reserved (read-only)
10-0 Y coordinate (row) of upper left corner, plus 1
SeeAlso: #M0058,#M0069
Bitfields for S3 Streams Processor window size:
Bit(s) Description (Table M0069)
31-27 reserved (read-only)
26-16 width in pixels - 1
15-11 reserved (read-only)
10-0 height in scan lines
SeeAlso: #M0058,#M0068
--------V-MA0008200--------------------------
MEM A000h:8200h - S3 ViRGE - MEMORY-MAPPED MEMORY-PORT CONTROL REGISTERS
Size: 40 BYTEs
Note: the S3 graphics processor registers can be mapped at either
linear 000A0000h or at offset 16M from the start of the linear
frame buffer
Format of S3 memory-maped port control registers:
Offset Size Description (Table M0070)
8200h DWORD FIFO control
8204h DWORD MIU control
8208h DWORD streams timeout
820Ch DWORD miscellaneous timeout
8210h 4 DWORDs ???
8220h DWORD DMA read base address
8224h DWORD DMA read stride width
SeeAlso: #M0057
--------V-MA00082E8--------------------------
MEM A000h:82E8h - S3 - MEMORY-MAPPED CURRENT Y POSITION REGISTER
Size: WORD
Note: the S3 graphics processor registers can be mapped at either
linear 000A0000h or at offset 16M from the start of the linear
frame buffer
SeeAlso: PORT 82E8h
--------V-MA00083B0--------------------------
MEM A000h:83B0h - S3 - MEMORY-MAPPED VGA REGISTERS
Size: 48 BYTEs
Note: the S3 graphics processor registers can be mapped at either
linear 000A0000h or at offset 16M from the start of the linear
frame buffer
SeeAlso: PORT 03B0h,PORT 03C0h,PORT 03D0h
--------V-MA0008504--------------------------
MEM A000h:8504h - S3 ViRGE - MEMORY-MAPPED SUBSYSTEM REGISTERS
Size: 12 BYTEs
Note: the S3 graphics processor registers can be mapped at either
linear 000A0000h or at offset 16M from the start of the linear
frame buffer
Format of S3 memory-mapped subsystem registers:
Offset Size Description (Table M0071)
8504h DWORD subsystem Control/Status Register (see PORT 42E8h,PORT 9AE8h)
on read:
bit 13 indicates whether graphics processor is busy
bits 12-8 indicate number of free FIFO slots
8508h DWORD ???
850Ch DWORD advanced function control (see PORT 4AE8h)
SeeAlso: #M0073,#M0057,#M0072
--------V-MA0008580--------------------------
MEM A000h:8580h - S3 - MEMORY-MAPPED DMA REGISTERS
Size: 32 BYTEs
Note: the S3 graphics processor registers can be mapped at either
linear 000A0000h or at offset 16M from the start of the linear
frame buffer
Format of S3 memory-mapped DMA registers:
Offset Size Description (Table M0072)
8580h DWORD start address in system memory
8584h DWORD transfer length
8588h DWORD transfer enable
858Ch DWORD ???
8590h DWORD DMA base address
8594h DWORD DMA write pointer
8598h DWORD DMA read pointer
859Ch DWORD DMA enable
SeeAlso: #M0057,#M0073
--------V-MA00086E8--------------------------
MEM A000h:86E8h - S3 - MEMORY-MAPPED ENHANCED REGISTERS
Size: ? BYTEs
Note: the S3 graphics processor registers can be mapped at either
linear 000A0000h or at offset 16M from the start of the linear
frame buffer
--------V-MA000A000--------------------------
MEM A000h:A000h - S3 - MEMORY-MAPPED COLOR PALETTE REGISTERS
Size: 448 BYTEs
Note: the S3 graphics processor registers can be mapped at either
linear 000A0000h or at offset 16M from the start of the linear
frame buffer
--------V-MA000A4D4--------------------------
MEM A000h:A4D4h - S3 - MEMORY-MAPPED BLT-FILL REGISTERS
Size: 60 BYTEs
Note: the S3 graphics processor registers can be mapped at either
linear 000A0000h or at offset 16M from the start of the linear
frame buffer
A4D4h DWORD ???
A4D8h DWORD ???
A4DCh DWORD ??? (set to 07FFh by S3_32.DLL)
A4E0h DWORD ??? (set to 07FFh by S3_32.DLL)
A4E4h DWORD ???
A4E8h DWORD ???
A4ECh DWORD ???
A4F0h
A4F4h DWORD ???
A4F8h
A4FCh DWORD ???
A500h DWORD ???
A504h DWORD ???
A508h DWORD ???
A50Ch DWORD ???
--------V-MA000A8D4--------------------------
MEM A000h:A8D4h - S3 - MEMORY-MAPPED LINE REGISTERS
Size: 172 BYTEs
Note: the S3 graphics processor registers can be mapped at either
linear 000A0000h or at offset 16M from the start of the linear
frame buffer
--------V-MA000ACD4--------------------------
MEM A000h:ACD4h - S3 - MEMORY-MAPPED POLYGON-FILL REGISTERS
Size: 172 BYTEs
Note: the S3 graphics processor registers can be mapped at either
linear 000A0000h or at offset 16M from the start of the linear
frame buffer
--------V-MA000B0D4--------------------------
MEM A000h:B0D4h - S3 - MEMORY-MAPPED 3D-LINE REGISTERS
Size: 172 BYTEs
Note: the S3 graphics processor registers can be mapped at either
linear 000A0000h or at offset 16M from the start of the linear
frame buffer
--------V-MA000B4D4--------------------------
MEM A000h:B4D4h - S3 - MEMORY-MAPPED 3D-TRIANGLE REGISTERS
Size: 172 BYTEs
Note: the S3 graphics processor registers can be mapped at either
linear 000A0000h or at offset 16M from the start of the linear
frame buffer
--------V-MA000FF00--------------------------
MEM A000h:FF00h - S3 - MEM-MAPPED "SCENIC HIGHWAY" (Local Periph. Bus) ACCESS
Size: 64 DWORDs
Note: the S3 graphics processor registers can be mapped at either
linear 000A0000h or at offset 16M from the start of the linear
frame buffer
SeeAlso: MEM A000h:8180h
Format of S3 Local Peripheral Bus memory-mapped registers:
Offset Size Description (Table M0073)
FF00h DWORD LPB mode (see #M0074)
FF04h DWORD LPB FIFO status (see #M0075)
FF08h DWORD interrupt status (see #M0076)
FF0Ch DWORD frame buffer address 0 (bits 21-0, multiple of 8)
offset within frame buffer at which to store incoming data from
LPB when Streams Processor double-buffer control (see #M0065)
bit 4 clear
FF10h DWORD frame buffer address 1 (bits 21-0, multiple of 8)
offset within frame buffer at which to store incoming data from
LPB when Streams Processor double-buffer control (see #M0065)
bit 4 is set
FF14h DWORD "direct address" = index for FF18h (see #M0077)
FF18h DWORD "direct data" (see #M0077)
Note: the direct address/direct data registers presumably rely
on the attached device inserting data into the digital video
stream, as on a Diamond Stealth64 Video, the "direct data"
appears to reflect the video stream data (i.e. it varies, but
with a pattern that depends on the video image, and stops
varying when video is frozen)
FF1Ch DWORD general purpose I/O (see #M0078)
FF20h DWORD LPB serial port -- I2C/DDC access (see #M0079)
FF24h DWORD input window size (high word = rows, low word = columns)
FF28h DWORD data offsets
(video alignment; high word = rows ; low word = columns)
FF2Ch DWORD horizontal decimation
bits 0-31 set indicate that bytes 0-31 (mod 32)
of each line should be dropped (in Video16 mode, each bit
controls a WORD); decimation is aligned with the start of
line as specified by the data offsets at FF28h
FF30h DWORD vertical decimation
bits 0-31 set indicate that lines 0-31 (mod 32) should be
dropped, i.e. setting this DWORD to 55555555h will drop
every other line; decimation starts with VSYNC regardless
of the data offsets specified at FF28h
FF34h DWORD line stride (number of bytes between starts of successive lines
of video data)
must be multiple of 4 -- lowest two bits forced to 0
FF38h 3 DWORDs unused??? (seem to echo FF34h)
FF40h 8 DWORDs LPB output FIFO - data transfer
writing to ANY of these DWORDs transfers a value to the FIFO;
this organization allows use of a REP MOVSD instruction to
fill the FIFO
on ISA bus, there must be a delay between successive writes
SeeAlso: #M0058
Bitfields for S3 Local Peripheral Bus LPB Mode register:
Bit(s) Description (Table M0074)
0 enable LPB
3-1 LPB operational mode
000 Scenic/MX2
001 Video 16 (PCI only)
010 Video 8 In
used by Philips SAA7110/SAA7111 and Diamond's DTV1100
011 Video 8 In/Out
used by CL-480
100 Pass-Through
send FIFO data written by CPU through the decimation logic
else reserved (Trio64V+)
4 LBP Reset
pulse this bit before changing operational mode
5 skip every other frame
=0 write all received frames to memory
6 disable byte-swapping
=0 incoming 8-bit video is in order U, Y0, V, Y1 (CL-480)
=1 incoming 8-bit video is in order Y0, U, Y1, V (SAA711x)
(refer to bit 26 below)
8-7 officially reserved
7 ??? messes up video image when set
9 LPB vertical sync input polarity
=0 active low
=1 active high
10 LPB horizontal sync input polarity
=0 active low
=1 active high
11 (write-only) CPU VSYNC
writing a 1 makes Trio act as if LPB VSYNC had been received
12 (write-only) CPU HSYNC
writing a 1 makes Trio act as if LPB HSYNC had been received
13 (write-only) load base address
writing a 1 causes an immediate load of the currently active base
address
15-14 reserved
17-16 maximum compressed data burst, LPB to Scenic/MX2
00 one DWORD
01 two DWORDs
10 three DWORDs
11 burst until empty (must ensure that MX2's 8-entry FIFO is not
overrun)
20-18 reserved
22-21 video FIFO threshold
number of filled slots at which to request that Trio's memory manager
begin to empty the FIFO (00 = one slot, 01 = two slots, 10 = four
slots, 11 = six slots)
23 reserved (read-only)
24 LPB clock source
=0 driven by SCLK (Pin194) (for Trio64-compatibility mode)
=1 driven by LCLK (Pin148) (default)
25 don't add line stride after first HSYNC within VSYNC
must be set if first HSYNC occurs before VSYNC goes active
26 invert LCLK (only has effect if bit 24 set)
27 reserved
28 (not yet on Trio64V+) current odd/even video field status
29 (not yet on Trio64V+) field inversion - when set, the LPB's FIELD pin
state is inverted before being reported in bit 28
30 reserved
31 (read-only) current state of CFLEVEL input (Pin182) in Video In/Out
mode (refer to bits 3-1)
SeeAlso: #M0073
Bitfields for S3 Local Peripheral Bus LPB FIFO status:
Bit(s) Description (Table M0075)
31 video FIFO 1 is almost empty (has exactly one full slot)
30 video FIFO 1 is empty
29 video FIFO 1 is full
28-23 reserved
22 video FIFO 0 is almost empty (has exactly one full slot)
21 video FIFO 0 is empty
20 video FIFO 0 is full
19-14 reserved
13 output FIFO is almost empty (has exactly one full slot)
12 output FIFO is empty
11 output FIFO is full
10-4 reserved
3-0 number of free four-byte slots in FIFO (there are 8 slots)
SeeAlso: #M0073,#M0076
Bitfields for S3 Local Peripheral Bus interrupt status:
Bit(s) Description (Table M0076)
31-25 reserved
24 drive serial port clock line low on receipt of start condition
(causes I2C wait states until interrupt handler responds to start cond)
23-20 reserved
19 enable interrupt on I2C start condition detection
18 enable interrupt on end of frame (VSYNC received)
17 enable interrupt on end of line (HSYNC received)
16 enable interrupt on LPB output FIFO empty
15-4 reserved
3 serial port detected I2C start condition
2 VSYNC received (end of frame)
1 HSYNC received (end of line)
0 LPB output FIFO emptied
Note: bits 3-0 are write-clear: writing a 1 to a bit resets it
SeeAlso: #M0073,#P0721
(Table M0077)
Values for S3 Local Peripheral Bus "direct address" index:
0000h CP3 installation (FF18h reads 00C3h if installed)
0001h ?
0002h ?
0003h ?
bit 7: ???
bits 6-0: ???
0004h ?
0005h ?
bits 7-0: ???
0020h ? (set to 107D4h, 1xxD4h by CP3.DLL))
0028h ?
0034h ? (set to 10000h by CP3.DLL)
0414h ? (set by CP3.DLL)
0500h ?
0504h ?
0508h ?
050Ch ?
0510h ?
SeeAlso: #M0073
Bitfields for S3 Local Peripheral Bus General-Purpose I/O:
Bit(s) Description (Table M0078)
3-0 values to drive onto LPB GP output lines whenever CR5C is written
7-4 values of GP input lines (read-only), latched whenever CR5C is read
31-8 unused (read-only 0)
SeeAlso: #M0073
Bitfields for S3 Local Peripheral Bus serial-port register:
Bit(s) Description (Table M0079)
0 I2C clock line [SCL] (write)
=1 tri-state SCL, allowing other devices to pull it low
1 I2C data line [SDA] (write)
=1 tri-state SDA, allowing other devices to pull it low
2 I2C clock line (read)
this bit reflect the actual state of the SCL line
3 I2C data line (read)
this bit reflect the actual state of the SDA line
4 enable I2C interface
=0 disable bits 0/1, forcing both SCL and SDA to be tri-stated
15-5 reserved (unused)
20-16 mirrors of bits 4-0
(these bits are on the data bus' byte lane 2 to make them accessible
via I/O port 00E2h)
Notes: see file I2C.LST for details of the I2C device registers accessible
through this interface (VPX3220A for Stealth64 Video 2001TV)
when the feature connector is disabled on the Stealth64 Video, these
bits are connected to the monitor's DDC data and clock lines
the official documentation erroneously lists the mirrors in bits 12-8
instead of 20-16
SeeAlso: #M0073,PORT 00E2h,#P0677
--------V-MB0000000--------------------------
MEM B000h:0000h - MDA TEXT BUFFER
Size: 4096 BYTEs
--------V-MB0000000--------------------------
MEM B000h:0000h - HGC+ RAMFont-MODE TEXT BUFFER
Size: 16384 BYTEs
Note: in RAMFont Mode 1, the memory is filled with the usual
character/attribute pairs; in RAMFont Mode 2, four bits of each
'attribute' byte is used to provide 12 bits for specifying the
character
--------V-MB0000000--------------------------
MEM B000h:0000h - HGC GRAPHICS BUFFER (PAGE 0)
Size: 32768 BYTEs
--------V-MB4000000--------------------------
MEM B400h:0000h - HGC+ RAMFont BUFFER
Size: 4096 BYTEs
Notes: apparently write-only
RAMFont Mode 1: 256 characters (8 bits each for char and attribute)
RAMFont Mode 2: 3072 characters (12 bits for char, 4 bits for attrib)
each character definition is 8 pixels wide (with 9th-column duplication
if appropriate) by 8-16 pixels high
--------V-MB8000000--------------------------
MEM B800h:0000h - CGA TEXT/GRAPHICS BUFFER
Size: 16384 BYTEs
--------V-MB8000000--------------------------
MEM B800h:0000h - EGA/VGA+ TEXT BUFFER
Size: 32768 BYTEs
--------V-MB8000000--------------------------
MEM B800h:0000h - HGC GRAPHICS BUFFER (PAGE 1)
Size: 32768 BYTEs
--------V-MBFF00000--------------------------
MEM BFF0h:0000h - ET4000/W32 ACL accelerator
Size: 169 BYTES
Format of ET4000/W32 memory-mapped registers:
Offset Size Description (Table M0080)
00h DWORD MMU Registers: memory base pointer register 0 (see #M0081)
04h DWORD MMU Registers: memory base pointer register 1 (see #M0081)
08h DWORD MMU Registers: memory base pointer register 2 (see #M0081)
0Ch 7 BYTEs ???
13h BYTE MMU Registers: MMU control register (see #M0082)
14h 28 BYTEs ???
30h BYTE Non-Queued Registers: suspend/terminate
31h BYTE Non-Queued Registers: operation state (see #M0083) (write-only)
32h BYTE Non-Queued Registers: sync enable
33h BYTE ???
34h BYTE Non-Queued Registers: interrupt mask
35h BYTE Non-Queued Registers: interrupt status
36h BYTE Non-Queued Registers: ACL status (read-only)
bit 1: read status (RDST) 1=ACL active, queue not empty
bit 0: write status (WRST) 1=queue full
37h 73 BYTEs ???
80h DWORD Queued Registers: pattern address (see #M0084)
84h DWORD Queued Registers: source address (see #M0084)
88h WORD Queued Registers: pattern Y offset (see #M0085)
8Ah WORD Queued Registers: source Y offset (see #M0085)
8Ch WORD Queued Registers: destination y offset (see #M0085)
8Eh BYTE Queued Registers: virtual bus size
8Fh BYTE Queued Registers: X/Y direction (see #M0086)
90h BYTE Queued Registers: pattern wrap (see #M0087)
91h BYTE ???
92h BYTE Queued Registers: source wrap (see #M0087)
93h BYTE ???
94h WORD Queued Registers: X position
96h WORD Queued Registers: Y position
98h WORD Queued Registers: X count (see #M0088)
9Ah WORD Queued Registers: Y count (see #M0088)
9Ch BYTE Queued Registers: routine control (see #M0089)
9Dh BYTE Queued Registers: reload control
9Eh BYTE Queued Registers: background ROP for mixing
9Fh BYTE Queued Registers: foreground ROP for mixing
A0h DWORD Queued Registers: destination address
A4h DWORD Queued Registers: internal pattern address
A8h DWORD Queued Registers: internal source address
Bitfields for ET4000/W32 memory base pointer register:
Bit(s) Description (Table M0081)
31-22 reserved
21-0 memory base pointer
SeeAlso: #M0080
Bitfields for ET4000/W32 MMU control register:
Bit(s) Description (Table M0082)
7 reserved
6-4 linear address control (LAC)
bit 6: MMU aperture 2
bit 5: MMU aperture 1
bit 4: MMU aperture 0
3 reserved
t2-0 aperture type (APT)
bit 2: MMU aperture 2
bit 1: MMU aperture 1
bit 0: MMU aperture 0
SeeAlso: #M0080
Bitfields for ET4000/W32 operation state register:
Bit(s) Description (Table M0083)
7-4 reserved
3 restart operation after ACL-interruption
2-1 reserved
0 restore status before ACL-interruption
SeeAlso: #M0080
Bitfields for ET4000/W32 memory address register:
Bit(s) Description (Table M0084)
31-22 reserved
21-0 memory base pointer
SeeAlso: #M0080
Bitfields for ET4000/W32 offset register:
Bit(s) Description (Table M0085)
15-12 reserved
11-0 Y offset
SeeAlso: #M0080
Bitfields for ET4000/W32 X/Y direction register:
Bit(s) Description (Table M0086)
7-2 reserved
1 X direction
0 Y direction
SeeAlso: #M0080
Bitfields for ET4000/W32 wrap register:
Bit(s) Description (Table M0087)
7 reserved
6-4 pattern Y wrap
000 = 1 line
001 = 2 lines
010 = 4 lines
011 = 8 lines
100 = reserved
101 = reserved
110 = reserved
111 = no wrap
3 reserved
2-0 pattern X wrap
000 = reserved
001 = reserved
010 = 4 byte
011 = 8 byte
100 = 16 byte
101 = 32 byte
110 = 64 byte
111 = no wrap
SeeAlso: #M0080
Bitfields for ET4000/W32 count register:
Bit(s) Description (Table M0088)
15-12 reserved
11-0 pixel count
SeeAlso: #M0080
Bitfields for ET4000/W32 routine control register:
Bit(s) Description (Table M0089)
7-6 reserved
5-4 routing of CPU address (ADRO)
00 don't use CPU address
01 CPU address is destination
10 reserved
11 reserved
3 reserved
2-0 routing of CPU data (DARQ)
000 don't use CPU data
001 CPU data is source data
010 CPU data is mixed data
011 reserved
100 CPU data is x-count
101 CPU data is y-count
10x reserved
SeeAlso: #M0080
--------V-MC0000000--------------------------
MEM C000h:0000h - VIDEO BIOS (EGA and newer)
Size: varies (usually 16K-24K for EGA, 24K-32K for VGA)
--------b-MC0000000--------------------------
MEM C000h:0000h OLIVETTI 640x400 GRAPHICS CARDS
Size: 62 BYTEs
SeeAlso: MEM 0040h:0088h"Olivetti"
Format of Olivetti 640x480 ROM signatures:
Offset Size Description (Table M0133)
00h WORD 55AAh adapter ROM signature (check this!)
...
10h 2 BYTEs "OL" if Olivetti EGA or VGA card
...
22h 2 BYTEs (Olivetti EGA/VGA)
"VG" for Olivetti VGA (supports 640x400 mode)
"EG" for Olivetti EGA including Olivetti EGA card 2
...
3Ch 2 BYTEs "PA" if Paradise card (supports 640x400 mode)
Note: These signatures can aid in the presence detection of an EGA or VGA
adapter supporting the 640x400 mode.
Olivetti PC models M15 and M19 do not support the 640x400 mode
(see INT 15h/C0h).
To decide if the 640x400 mode is supported by an Olivetti EGA card
(only the Olivetti EGA card 2 supports it), also check that bit 7
and 5 are set at 0040h:0088h.
--------V-MC000xxxx--------------------------
MEM C000h:xxxxh - VESA VBE v3.0 PROTECTED MODE INFORMATION BLOCK
Size: 20 BYTEs
Range: starting at any byte within the first 32K of segment C000h
Format of VESA VBE 3.0 Protected Mode Information Block:
Offset Size Description (Table M0127)
00h 4 BYTEs signature "PMID"
04h WORD offset of protected-mode entry point within BIOS
06h WORD offset of protected-mode initialization entry point
08h WORD selector for BIOS data area emulation block
(default 0000h, must be set by protected-mode OS to 16-bit
read/write data selector with limit of at least 0600h)
0Ah WORD selector to access physical memory at A0000h
(default A000h, must be set by protected-mode OS to 16-bit
read/write data selector with 64K limit)
0Ch WORD selector to access physical memory at B0000h
(default B000h, must be set by protected-mode OS to 16-bit
read/write data selector with 64K limit)
0Eh WORD selector to access physical memory at B8000h
(default B800h, must be set by protected-mode OS to 16-bit
read/write data selector with 32K limit)
10h BYTE protected-mode execution (default 00h; set to 01h by OS when
BIOS image is running in protected mode)
11h BYTE checksum byte for entire structure (this byte forces 8-bit
sum of all bytes to 00h)
--------h-mC0000000--------------------------
MEM C0000000h - Weitek "Abacus" math coprocessor
Size: 4096 BYTEs
--------B-MC8000000--------------------------
MEM C800h:0000h - HARD DISK BIOS
Size: varies (usually 8K or 16K)
--------V-MC8001C00--------------------------
MEM C800h:1C00h - IBM XGA, XGA/A - MEMORY-MAPPED REGISTERS
Range: any 8K boundary within segments C000h to DFFFh
Notes: The XGA memory mapped registers can be assigned to the last 1K block in
in each 8K block in the range of C0000h-DFFFFh; the base offset of
the 128 memory mapped lcoation for a particular XGA instance is
Segment:(1C00h+instance*80h) for each XGA installed in a system
(default instance is 6). The instance number may be read from the
XGA's Programmable Option Select registers
The XGA/A (PS/2 adapter) uses the 7KB area below the memory-mapped
register area for ROM data; the XGA (PS/2 onboard) has included
this area in it's video BIOS ROM.
Most of the memory mapped registers are from the graphics coprocessor,
while the I/O-registers are for the display controller.
--------V-MC0007FF8--------------------------
MEM C000h:7FF8h - Matrox MGA Video Adapters - CARD VENDOR ID
Size: WORD
Desc: contains the PCI vendor ID for the card vendor; this is written into
the video controllers PCI subsystem-vendor-ID field
SeeAlso: MEM C000h:7FFAh,MEM C000h:7FFCh
--------V-MC0007FFA--------------------------
MEM C000h:7FFAh - Matrox MGA Video Adapters - HARDWARE REVISION ID
Size: BYTE
SeeAlso: MEM C000h:7FF8h,MEM C000h:7FFCh
--------V-MC0007FFC--------------------------
MEM C000h:7FFCh - Matrox MGA Video Adapters - OFFSET OF PINS DATA STRUCTURE
Size: WORD
SeeAlso: INT 10/AX=4F14h"Matrox",#00126,MEM C000h:7FF8h
-------b-MF0000000--------------------------
MEM F000h:0000h - WANG PC MEMORY MAPPED SCREEN BUFFER
Size: ???
Note: This is used by Peter Reilley's portable binary editor and viewer BEAV
to directly write into the Wang PC's video screen buffer (instead
of using INT 10/AH=02h,09h) after it has been mapped in by writing
BYTE 01h to the screen port (PORT 1010h for the 1st screen, 1020h
for the 2nd, 1030h for the 3rd, 1040h for the 4th). It will be
unmapped afterwards by writing BYTE 00h to the screen port.
Note, that this is only necessary when the INT 21/AX=4402h detection
method resulted in non-IBM PC characteristic (return values other
than 11h).
SeeAlso: MEM FC00h:3FC2h, INT 88h/AL=01h, INT 21h/4402h
--------B-MF0002DC5-------------------------
MEM F000h:2DC5h - IBM AT SIGNATURE
Size: ??? signature
Note: Original IBM ATs with a multi-sector hard disk ROM-BIOS bug can be
identified by checking a (currently unknown) signature at this
location. This is known to be done by the Concurrent CP/M-86 family.
Presumably the OS will then prohibit timer ISR dispatches within
a code window of F000h:2D95h..F000h:2DD4h.
--------A-MF0006000--------------------------
MEM F000h:6000h - IBM PC ROM BASIC
Size: 32768 BYTEs
--------b-MF000800C-------------------------
MEM F000h:800Ch ZENITH
Size: 8 BYTEs signature "ZDS CORP"
Note: Zenith machines may have 256 Kb extra memory at 0FA0000h linear.
----------MF000C000--------------------------
MEM F000h:C000h - Tandy ROM BIOS ID BYTE
Size: BYTE
Note: If the BYTE at this location is equal to 21h, some Microsoft software
assumes this is a Tandy machine, and for example trusts the bits 1-0
at 0040h:00B5h.
SeeAlso: MEM 0040h:00B5h"Tandy",INT 15/AH=C0h
--------b-MFC000050--------------------------
MEM FC00h:0050h - OLIVETTI Mxxx PC SIGNATURE
Size: 4 BYTEs (or more) "OLIV"
Note: used by several Olivetti PCs, including M15, M19
SeeAlso: INT 15/AH=C0h
--------b-MFC003FC2--------------------------
MEM FC00h:3FC2h - WANG PC SIGNATURE
Size: 4 BYTEs containing the signature "WANG"
Note: This is used by Peter Reilley's portable binary editor and viewer
BEAV to detect a Wang PC.
SeeAlso: INT 88/AL=01h,INT 21/AX=4402h,INT 15/AH=C0h
--------B-MF000E000--------------------------
MEM F000h:E000h - ORIGINAL IBM PC ROM BIOS
Size: 8192 BYTEs
-------b-MF000FFD9-------------------------
MEM F000h:FFD9h - EISA MACHINE ID
Size: 4 BYTEs signature "EISA"
SeeAlso: INT 15/AH=E801h
--------b-MF000FFE0-------------------------
MEM F000h:FFE0h - COMPAQ 386 MACHINES
Size: 16 BYTEs
SeeAlso: MEM 80C00000h
Format of Compaq 386 Memory Configuration Data:
Offset Size Description (Table M0134)
00h WORD Compaq 32-bit extra built-in memory available (FFFFh if not)
02h WORD Total size of Compaq extra memory
04h WORD Count of available paragraphs of Compaq extra memory
06h WORD Paragraph address of last paragraph in use as Compaq extra
memory
08h 2 BYTEs product class signature "03"
0Ah 6 BYTEs signature "03COMPAQ"
Notes: The full "03COMPAQ" signature can be found in (at least) Compaq 386
machines which have dual harddisk controller. (see also CMOS 70h)
However, the 6-byte "COMPAQ" signature also seems to be available
in other Compaq machines with dual hard disk controllers, at least
the MS-DOS/PC DOS IO.SYS/IBMBIO.COM checks for if before it calls
INT 15/AX=E400h and INT 15/AX=E480h.
Compaq's extra memory is mappable memory starting at FE00h:0000h
growing downwards. It can be made available for example with
Novell DOS 7+ EMM386.EXE /COMPAQ=ON.
Although this structure resides at a ROM-address it is actually write-
protected RAM. To write to the structure to map in Compaq extra
memory the write-protection must be temporarily disabled by setting
bit 1 at WORD 80C00000h.
----------MF000FFE8--------------------------
MEM F000h:FFE8h - Compaq - MACHINE SIGNATURE STRING
Size: 8 BYTEs
Desc: if this area contains the ASCII string "03COMPAQ", then this is a
Compaq machine
SeeAlso: CMOS 1Bh"AMI"
--------H-MF000FFF0--------------------------
MEM F000h:FFF0h - RESET JUMP
Size: 5 BYTEs
--------B-MF000FFF5--------------------------
MEM F000h:FFF5h - ASCII BIOS DATE
Size: 8 BYTEs
--------B-MF000FFFD--------------------------
MEM F000h:FFFDh - OFTEN USED TO ENSURE CORRECT BIOS CHECKSUM
Size: BYTE
--------B-MF000FFFE--------------------------
MEM F000h:FFFEh - MACHINE TYPE CODE
Size: BYTE
SeeAlso: INT 15/AH=C0h
--------X-MF000xxx0--------------------------
MEM F000h:xxx0h - PCI IRQ Routing Table Specification v1.0
Size: N paragraphs (N >= 2)
InstallCheck: scan for the signature string "$PIR" followed by a valid
PCI IRQ Routing Table
Range: any paragraph boundary within the range F0000h to FFFFFh
Format of PCI IRQ Routing Table v1.0:
Offset Size Description (Table M0090)
00h 4 BYTEs signature "$PIR"
04h WORD version (0100h for v1.0)
06h WORD table size in bytes
08h BYTE bus number for PCI Interrupt Router
09h BYTE device/function number for PCI Interrupt Router
0Ah WORD bitmap of PCI-exclusive IRQs (bit 0 = IRQ0, etc.)
0Ch WORD PCI vendor ID for compatible PCI Interrupt Router
0Eh WORD PCI device ID for compatible PCI Interrupt Router
10h DWORD Miniport data
14h 11 BYTEs reserved (0)
1Fh BYTE checksum (set to make 8-bit sum of bytes in entire structure
equal 00h)
--- optional data ---
20h 16 BYTEs first slot entry (see #M0091)
...
16 BYTEs Nth slot entry
Format of PCI IRQ Routing Table slot entry:
Offset Size Description (Table M0091)
00h BYTE PCI bus number
01h BYTE PCI device number (bits 7-3)
02h BYTE link value for INTA#
03h WORD IRQ bitmap for INTA#
05h BYTE link value for INTB#
06h WORD IRQ bitmap for INTB#
08h BYTE link value for INTC#
09h WORD IRQ bitmap for INTC#
0Bh BYTE link value for INTD#
0Ch WORD IRQ bitmap for INTD#
0Eh BYTE slot number (00h = motherboard, other = vendor-specific)
0Fh BYTE reserved
SeeAlso: #M0090,#01260 at INT 1A/AX=B406h
--------B-MF000xxxx--------------------------
MEM F000h:xxxxh - AWARD Flash Hook
Format of AWARD Flash BIOS interface:
Offset Size Description (Table M0092)
00h 8 BYTEs signature "AWDFLASH"
08h WORD offset in F000h of FAR function: Get ???
Return: BL = ??? (00h)
0Ah WORD offset in F000h of FAR function: ???
0Ch WORD offset in F000h of FAR function: ???
0Eh WORD offset in F000h of FAR function: ???
10h WORD offset in F000h of FAR function: ???
12h WORD offset in F000h of FAR function: Disable Shadowing
14h WORD offset in F000h of FAR function: Enable Shadowing
16h WORD offset in F000h of FAR function: Get ???
Return: DS:SI -> ??? (30 bytes?)
18h WORD offset in F000h of FAR function: Set ???
DS:SI -> ??? (appears to be same as previous function)
Note: the AWDFLASH utility copies the ROM from F000h and uses the copy
instead of the original F000h:xxxxh addresses
--------B-MF000xxxx--------------------------
MEM F000h:xxxxh - Asustek Flash Hook
Format of Asustek Flash interface:
Offset Size Description (Table M0093)
00h 10 BYTEs signature "ASUS_FLASH"
0Ah 6 BYTEs blanks (padding)
10h WORD interface version??? (current PFLASH.EXE requires 0101h)
12h DWORD -> position-independent code to enable shadowing
16h WORD size of code pointed at by previous field (<= 0400h)
18h DWORD -> position-independent code to disable shadowing
1Ch WORD size of code pointed at by previous field (<= 0400h)
--------p-Mxxxxxxx0--------------------------
MEM xxxxh:xxx0h - Advanced Configuration and Power Interface Spec (ACPI) v0.9+
Range: any paragraph boundary in the first kilobyte of the XBDA, the last
kilobyte of conventional memory, or from E000h:0000h to F000h:FFE0h
Note: scan paragraph boundaries for the signature string "RSD PTR ", followed
by a valid Root System Description Pointer structure (see #M0094)
SeeAlso: INT 15/AX=E820h
!!!acpi\acpi10.pdf p.194
Format of ACPI Root System Description Pointer structure:
Offset Size Description (Table M0094)
00h 8 BYTEs signature "RSD PTR "
08h BYTE checksum (entire structure, including this byte, must
add up to zero)
09h 6 BYTEs OEM identifier
0Fh BYTE reserved (0)
10h DWORD physical address of Root System Description Table (see #M0096)
SeeAlso: #M0096
Format of ACPI System Description Table header:
Offset Size Description (Table M0095)
00h 4 BYTEs signature
04h DWORD length of table in bytes, including this header
08h BYTE revision of specification corresponding to signature
01h for both v0.9 and v1.0
09h BYTE checksum (set such that entire table sums to 00h)
0Ah 6 BYTEs OEM identification
10h 8 BYTEs OEM table identifier
18h 4 BYTEs OEM revision number
---ACPI v1.0---
1Ch 4 BYTEs vendor ID for table-creation utility used
20h 4 BYTEs revision of table-creation utility
SeeAlso: #M0094,#M0096,#M0099,#M0097,#M0100,#M0105,#M0108,#M0110
Format of ACPI Root System Description Table:
Offset Size Description (Table M0096)
00h 36 BYTEs System Description Table Header (see #M0095)
signature "RSDT"
24h N DWORDs physical addresses of other description tables
(see #M0099,#M0097,#M0100,#M0105,#M0108,#M0109)
Notes: the number of table pointers is implied by the table length
field in the header (at offset 04h)
for ACPI v0.9, the header is eight bytes smaller and thus all
following offsets are 8 less
SeeAlso: #M0094
Format of ACPI Fixed ACPI Description Table:
Offset Size Description (Table M0097)
00h 36 BYTEs System Description Table Header (see #M0095)
signature "FACP"
24h DWORD physical address of the Firmware ACPI Control Structure
(see #M0105)
28h DWORD physical address of the Differentiated System Description Table
(see #M0099)
2Ch BYTE interrupt mode
00h dual PIC (industry-standard AT-type)
01h multiple APIC (see #M0100)
else reserved
2Dh BYTE reserved
2Eh WORD system vector of SCI interrupt
30h DWORD I/O port address of SMI command port
34h BYTE value to write to SMI comamnd port to disable SMI ownership
of ACPI hardware registers
35h BYTE value to write to SMI comamnd port to re-enable SMI ownership
of ACPI hardware registers
36h BYTE (v1.0) value to write to SMI command port to enter S4BIOS state
00h if not supported
37h BYTE reserved
38h DWORD I/O port address of Power Management 1a Event Register Block
3Ch DWORD I/O port address of Power Management 1b Event Register Block
(optional, 00000000h if not supported)
40h DWORD I/O port address of Power Management 1a Control Register Block
44h DWORD I/O port address of Power Management 1b Control Register Block
(optional, 00000000h if not supported)
48h DWORD I/O port address of Power Management 2 Control Register Block
(optional, 00000000h if not supported)
4Ch DWORD I/O port address of Power Management Timer Control Reg. Block
50h DWORD I/O port address of Generic Purpose Event 0 Register Block
(optional, 00000000h if not supported)
54h DWORD I/O port address of Generic Purpose Event 1 Register Block
(optional, 00000000h if not supported)
58h BYTE size of Power Management 1a/1b Event Register Block (>= 4)
59h BYTE size of Power Management 1a/1b Control Register Block (>= 1)
5Ah BYTE size of Power Management 2 Control Register Block (>= 1)
5Bh BYTE size of Power Management Timer Control Register Block (>= 4)
5Ch BYTE size of Generic Purpose Event 0 Register Block (multiple of 2)
5Dh BYTE size of Generic Purpose Event 1 Register Block (multiple of 2)
5Eh BYTE offset within General Purpose Event model for GPE1-based events
5Fh BYTE reserved
60h WORD worst-case hardware latency (microseconds) for entering/leaving
state C2; >100 if C2 not supported
62h WORD worst-case hardware latency (microseconds) for entering/leaving
state C3; >1000 if C3 not supported
64h WORD size of contiguous cacheable memory which must be read to flush
all dirty lines from a processor's memory cache; use if
fixed feature flag WBINVD (see #M0098) is clear
0000h if flushing not supported
66h WORD memory stride size (in bytes) to flush processor's memory cache
68h BYTE bit index of processor's duty cycle setting within the
processor's P_CNT register
69h BYTE size of processor's duty cycle setting in bits
6Ah BYTE index within RTC CMOS RAM of the day-of-month alarm value
00h = not supported
6Bh BYTE index within RTC CMOS RAM of the month-of-year alarm value
00h = not supported
6Ch BYTE index within RTC CMOS RAM of the century alarm value
00h = not supported
6Dh BYTE reserved
6Eh DWORD fixed feature flags (see #M0098)
SeeAlso: #M0094,CMOS 7Dh,CMOS 7Eh,CMOS 7Fh
Bitfields for ACPI Fixed Feature Flags:
Bit(s) Description (Table M0098)
0 WBINVD instruction is correctly supported by processor
1 WBINVD instruction flushes all caches and maintains coherency, but
does not guarantee invalidation of all caches
2 all processors support C1 sleep state
3 C2 sleep state is configured to work on multiprocessor system
---v0.9---
4 power button is handled as a generic feature
5 RTC wake-up state is not supported in fixed register space
6 TMR_VAL size
=0 24 bits
=1 32 bits
7-31 reserved
---v1.0---
4 power button is handled as a control method device
5 =0 sleep button is handled as a fixed feature programming mode
=1 control method device, or no sleep button
6 RTC wake-up state is not supported in fixed register space
7 RTc alarm can wake system from S4 state
8 TMR_VAL size
=0 24 bits
=1 32 bits
9-31 reserved
SeeAlso: #M0097
Format of ACPI Differentiated System Description Table:
Offset Size Description (Table M0099)
00h 36 BYTEs System Description Table Header (see #M0095)
signature "DSDT"
24h complex byte stream; refer to ACPI document and software
SeeAlso: #M0094
Format of ACPI Multiple APIC Description Table:
Offset Size Description (Table M0100)
00h 36 BYTEs System Description Table Header (see #M0095)
signature "APIC"
24h DWORD physical address of the local APIC in each processor's address
space
28h DWORD multiple-APIC flags (see #M0101)
2Ch 12N BYTEs APIC structures (see #M0102,#M0104)
first byte of each is type, second is length; types other than
00h and 01h are currently reserved and should be skipped
SeeAlso: #M0094
Bitfields for ACPI Multiple APIC Description Table flags:
Bit(s) Description (Table M0101)
0 system contains AT-compatible dual 8259 interrupt controllers in
addition to APICs
1-31 reserved (0)
SeeAlso: #M0100
Format of ACPI Local APIC Structure:
Offset Size Description (Table M0102)
00h BYTE structure type (00h = Processor Local APIC)
01h BYTE length of this structure (0Ch for v0.9, 08h for v1.0)
02h BYTE processor ID
03h BYTE processor's local APIC ID
---v0.9---
04h DWORD physical address of APIC
08h DWORD flags (TBD)
--v1.0---
04h DWORD flags (see #M0103)
SeeAlso: #M0100,#M0104
Bitfields for ACPI Local APIC flags:
Bit(s) Description (Table M0103)
0 APIC enabled
1-31 reserved (0)
SeeAlso: #M0102
Format of ACPI I/O APIC Structure:
Offset Size Description (Table M0104)
00h BYTE structure type (00h = Processor Local APIC)
01h BYTE 0Ch (length of this structure)
02h BYTE I/O APIC's ID
03h BYTE reserved (0)
04h DWORD physical address of the APIC
08h DWORD number of first system interrupt vector for APIC
SeeAlso: #M0100,#M0102
Format of ACPI Firmware ACPI Control Structure:
Offset Size Description (Table M0105)
00h 4 BYTEs signature "FACS"
04h DWORD length of entire structure in bytes (>= 40h)
08h DWORD value of system's hardware signature at last boot
0Ch DWORD real-mode ACPI OS waking vector
if nonzero, control is transferred to this address on next BIOS
POST
10h DWORD global lock (see #M0107)
14h DWORD (v1.0) firmware control structure flags (see #M0106)
18h 44 BYTEs reserved (0)
Notes: this structure is located on a 64-byte boundary anywhere in the
first 4GB of memory
the BIOS is required to omit the address space containing this
structure from system memory in the system's memory map
SeeAlso: #M0094,INT 15/AX=E820h
Bitfields for ACPI Firmware Control Structure Feature flags:
Bit(s) Description (Table M0106)
0 system supports S4BIOS_REQ
=0 operating system must save/restore memory state in order to go to S4
1-31 reserved (0)
SeeAlso: #M0105
Bitfields for ACPI Embedded Controller Arbitration Structure:
Bit(s) Description (Table M0107)
0 request for Global Lock ownership is pending
1 Global Lock is currently owned
2-31 reserved
SeeAlso: #M0105
Format of ACPI Persistent System Description Table:
Offset Size Description (Table M0108)
00h 36 BYTEs System Description Table Header (see #M0095)
signature "PSDT"
24h complex byte stream; refer to ACPI document and software
SeeAlso: #M0094
Format of ACPI Secondary System Description Table:
Offset Size Description (Table M0109)
00h 36 BYTEs System Description Table Header (see #M0095)
signature "SSDT"
24h complex byte stream; refer to ACPI document and software
SeeAlso: #M0094
Format of ACPI Smart Battery Description Table:
Offset Size Description (Table M0110)
00h 36 BYTEs System Description Table Header (see #M0095)
signature "SBST"
24h DWORD energy level in mWh at which system should warn user
28h DWORD energy level in mWh at which system should automatically enter
sleep state
2Ch DWORD energy level in mWh at which system should perform an emergency
shutdown
SeeAlso: #M0094
----------Mxxxxxxx0---------------------------
MEM xxxxh:xxx0h - BIOS32 Service Directory
InstallCheck: scan paragraph boundaries E000h to FFFFh for signature string
"_32_", followed by a valid header structure (see #F0021)
SeeAlso: CALL xxxxh:xxxxh"BIOS32"
----------Mxxxxxxx0---------------------------
MEM xxxxh:xxx0h - Desktop Management Interface / System Management BIOS
InstallCheck: scan paragraph boundaries F000h to FFFFh for signature string
"_DMI_", followed by a valid header structure (see #M0111,#M0112)
Format of Desktop Management Interface entry-point structure:
Offset Size Description (Table M0111)
00h 5 BYTEs signature "_DMI_"
05h BYTE checksum of this structure (forces 8-bit sum of bytes to 00h)
06h WORD total length of SMBIOS structure table, in bytes
08h DWORD 32-bit physical address of read-only SMBIOS structure table
(see #F0059)
0Ch WORD number of SMBIOS structures
0Eh BYTE BCD SMBIOS revision (high nybble = major, low = minor)
!!!ftp://download.intel.com/ial/wfm/smbios.pdf
SeeAlso: #M0112
Format of System Management BIOS entry-point structure:
Offset Size Description (Table M0112)
00h 4 BYTEs signature "_SM_"
04h BYTE checksum of this structure (forces 8-bit sum of bytes to 00h)
05h BYTE length of structure in bytes (1Fh for v2.1+)
06h BYTE major version of specification
07h BYTE minor version of specification (01h = vX.1, 16h = vX.22)
08h WORD size of largest SMBIOS structure (see also #F0046)
0Ah BYTE revision of this data structure
00h SMBIOS v2.1-2.3
01h-FFh reserved for future versions
0Bh 5 BYTEs revision-specific data (currently unused)
10h 5 BYTEs intermediate anchor string "_DMI_"
15h BYTE checksum of intermediate entry-point structure
(forces 8-bit sum of bytes 10h-1Eh to 00h)
16h WORD total length of SMBIOS structure table, in bytes
18h DWORD 32-bit physical address of read-only SMBIOS structure table
(see #F0059)
1Ch WORD number of SMBIOS structures
1Eh BYTE BCD SMBIOS revision (high nybble = major, low = minor)
00h if specification version only given in bytes 06h/07h
BUG: due to an error in the v2.1 specification, some implementations might
indicate a length of 1Eh bytes instead of 1Fh
SeeAlso: #M0111
----------Mxxxxxxx0--------------------------
MEM xxxxh:xxx0h - Multiprocessor Specification - FLOATING POINTER STRUCTURE
InstallCheck: scan paragraph boundaries for the signature string "_MP_",
followed by a valid floating pointer structure (see #M0113)
Range: any paragraph boundary in the first kilobyte of the XBDA, the last
kilobyte of conventional memory, or from F000h:0000h to F000h:FFE0h
SeeAlso: MEM FEE00000h
Format of Multiprocessor Specification Floating Pointer structure:
Offset Size Description (Table M0113)
00h 4 BYTEs signature "_MP_"
04h DWORD physical address of MP configuration table (see #M0114)
00000000h if no configuration table
08h BYTE length of this structure in paragraphs (currently 01h)
09h BYTE revision of MP specification supported
01h = v1.1
04h = v1.4
0Ah BYTE checksum (8-bit sum of entire structure, including this
byte, must equal 00h)
0Bh BYTE MP feature byte 1: system configuration type
00h: MP configuration table present
nonzero: default configuration implemented by system
0Ch BYTE MP feature byte 2
bit 7: IMCR present
bits 6-0: reserved (0)
0Dh 3 BYTEs MP feature bytes 3-5 (reserved, must be 00h)
Format of Multiprocessor Specification configuration table header:
Offset Size Description (Table M0114)
00h 4 BYTEs signature "PCMP"
04h WORD length of base configuration table in bytes, including
this header
06h BYTE revision of MP specification supported
01h = v1.1
04h = v1.4
07h BYTE checksum of entire base configuration table
08h 8 BYTEs OEM identifier
10h 12 BYTEs product ID
1Ch DWORD physical address to OEM-defined configuration table
00000000h if not present
20h WORD size of base OEM table in bytes (0000h if not present)
22h WORD number of entries in variable portion of base table
24h DWORD address of local APIC (see also MEM FEE0h:0020h)
28h WORD length of extended entries following end of base table
(in bytes)
2Ah BYTE checksum for extended table entries (includes only
extended entries following base table)
2Ch var configuration table entries (see #M0115)
SeeAlso: #M0113
Format of Multiprocessor Specification configuration table entries:
Offset Size Description (Table M0115)
00h BYTE entry type code
00h processor
01h bus
02h I/O APIC
03h I/IO interrupt assignment
04h local interrupt assignment
80h system address space mapping
81h bus hierarchy descriptor
82h compatibility bus address space modifier
---processor---
01h BYTE local APIC identifier
02h BYTE local APIC version
03h BYTE CPU flags
bit 0: processor usable
bit 1: bootstrap processor
04h WORD CPU type
bits 11-8: CPU family
bits 7-4: CPU model
bits 3-0: stepping
(bits 11-0 all set indicate non-Intel-compatible CPU)
06h 2 BYTEs unused
08h DWORD feature flags (as returned by Pentium CPUID instruction)
0Ch 8 BYTEs reserved
---bus---
01h BYTE bus ID (assigned sequentially from 00h by BIOS)
02h 6 BYTEs bus type (blank-padded ASCII string) (see #M0116)
---I/O APIC---
01h BYTE APIC identifier
02h BYTE APIC version
03h BYTE I/O APIC flags
bit 0: enabled
bits 7-1: reserved
04h DWORD base address for APIC
---I/O,local interrupt assignment---
01h BYTE interrupt type
00h vectored interrupt (from APIC)
01h NMI
02h system management interrupt
03h vectored interrupt (from external PIC)
02h BYTE APIC control (see #M0117)
03h BYTE unused
04h BYTE source bus identifier
05h BYTE source bus IRQ
06h BYTE destination I/O APIC identifier
07h BYTE destination I/O APIC interrupt pin number
---system address space mapping---
01h BYTE entry length (14h)
02h BYTE bus ID
03h BYTE address type (00h I/O, 01h memory, 02h prefetch)
04h QWORD starting address of region visible to bus
0Ch QWORD length of region visible to bus
---bus hierarchy descriptor---
01h BYTE entry length (08h)
02h BYTE bus ID
03h BYTE bus information
bit 0: subtractive decoding
04h BYTE ID of parent bus
05h 3 BYTEs reserved
---compatibility bus address space modifier---
01h BYTE entry length (08h)
02h BYTE bus ID
03h BYTE address modifier
bit 0: remove address ranges in predefined range list from
bus's address space
04h DWORD number indicating predefined address space range to be removed
00h ISA-compatible I/O range (x100h-x3FFh and aliases)
01h VGA-compatible I/O range (x3B0h-x3BBh,x3C0h-x3DFh,aliases)
SeeAlso: #M0114
(Table M0116)
Values for Multiprocessor Specification bus name:
"CBUS" Corollary CBus
"CBUSII" Corollary CBus II
"EISA"
"FUTURE" IEEE FutureBus
"INTERN" internal bus
"ISA"
"MBI" Multibus I
"MBII" Multibus II
"MCA" Microchannel
"MPI"
"MPSA"
"NUBUS" Apple Macintosh NuBus
"PCI"
"PCMCIA"
"TC" DEC TurboChannel
"VL" VESA Local Bus
"VME" VMEbus
"XPRESS" Express System Bus
SeeAlso: #M0115
Bitfields for Multiprocessor Specification APIC control:
Bit(s) Description (Table M0117)
1-0 input signal polarity
00 conforms to bus specification
01 active high
10 reserved
11 active low
3-2 trigger mode
00 conforms to bus specification
01 edge-triggered
10 reserved
11 level-triggered
SeeAlso: #M0115
--------H-mFEC00000--------------------------
MEM FEC00000h - Pentium - 82379AB I/O APIC - I/O REGISTER SELECT
Size: DWORD
Desc: bits 7-0 of the I/O Register Select memory location specify which
of the APIC's registers appears in the I/O Window at FExxx010h
Range: the Multiprocessor Specification calls for I/O APICs to be memory-
mapped on 4K boundaries between FEC00000h and FEDFC000h; the Intel
82379AB I/O APIC can be memory-mapped on any 1K boundary within
FEC0000h-FEC0F800h
Note: this memory-mapped register is also supported by the Intel 82093AA
I/O APIC
SeeAlso: MEM FEC00010h,MEM FEE00000h,MEM xxxxh:xxx0h"Multiprocessor"
--------H-mFEC00010--------------------------
MEM FEC00010h - Pentium - 82379AB I/O APIC - I/O WINDOW
Size: DWORD
Range: the Multiprocessor Specification calls for I/O APICs to be memory-
mapped on 4K boundaries between FEC00000h and FEDFC000h
Note: this memory-mapped register is also supported by the Intel 82093AA
I/O APIC
SeeAlso: MEM FEC00010h
(Table M0118)
Values for Intel 82379AB/82093AA I/O APIC registers:
00h APIC ID
01h APIC version (read-only)
bits 31-24: reserved
bits 23-16: maximum redirection entry
bits 15-8: reserved
bits 7-0: APIC version (11h for 82093AA)
02h APIC arbitration ID (read-only)
bits 31-28: reserved
bits 27-24: arbitration ID
bits 23-0: reserved
10h-11h redirection table entry 0 (10h=low DWORD, 11h=high DWORD)
12h-13h redirection table entry 1 (see !!!)
...
2Eh-2Fh redirection table entry 15
---82093AA only---
30h-31h redirection table entry 16
...
3Eh-3Fh redirection table entry 23
Bitfields for APIC redirection table entry:
Bit(s) Description (Table M0119)
63-56 destination
!!!29056601.pdf pg. 10
55-17 reserved
16 interrupt mask
15 trigger mode
14 remote IRR (read-only)
13 interrupt input pin polarity
12 delivery status (read-only)
11 destination mode
10-8 delivery mode
7-0 interrupt vector (10h-FEh)
--------H-mFEE00000--------------------------
MEM FEE00000h - Pentium - LOCAL APIC
Size: 4096 BYTEs
Notes: the Advanced Programmable Interrupt Controller built into
multiprocessor-capable Pentiums (P54C, etc. -- basically 75MHz and
faster Pentiums) maps its registers into the top of the physical
address space on data reads and writes, but not on code reads;
data accesses to the APIC registers do not cause external bus
cycles
the APIC's registers are only visible when the APIC is enabled (which
occurs at CPU reset when external data lines contain proper signals);
all accesses to APIC registers should use 32-bit reads or writes, as
8-bit and 16-bit accesses may produce unpredictable results
the PentiumPro (P6) permits the address at which the local APIC
appears to be changed with Model-Specific Register 0000001Bh
SeeAlso: MEM FEC00000h,MEM FEE00020h,MEM xxxxh:xxx0h"Multiprocessor"
SeeAlso: MSR 0000001Bh
--------H-mFEE00020--------------------------
MEM FEE00020h - Pentium - LOCAL APIC - LOCAL APIC ID REGISTER
Size: DWORD
SeeAlso: MEM FEE00030h
--------H-mFEE00030--------------------------
MEM FEE00030h - Pentium - LOCAL APIC - LOCAL APIC VERSION REGISTER
Size: DWORD
Note: read-only
SeeAlso: MEM FEE00020h
--------H-mFEE00040--------------------------
MEM FEE00040h - Pentium - LOCAL APIC - RESERVED
SeeAlso: MEM FEE00000h
--------H-mFEE00050--------------------------
MEM FEE00050h - Pentium - LOCAL APIC - RESERVED
SeeAlso: MEM FEE00000h
--------H-mFEE00060--------------------------
MEM FEE00060h - Pentium - LOCAL APIC - RESERVED
SeeAlso: MEM FEE00000h
--------H-mFEE00070--------------------------
MEM FEE00070h - Pentium - LOCAL APIC - RESERVED
SeeAlso: MEM FEE00000h
--------H-mFEE00080--------------------------
MEM FEE00080h - Pentium - LOCAL APIC - TASK PRIORITY REGISTER (TPR)
Size: DWORD
--------H-mFEE00090--------------------------
MEM FEE00090h - Pentium - LOCAL APIC - ARBITRATION PRIORITY REGISTER (APR)
Size: DWORD
Note: read-only
--------H-mFEE000A0--------------------------
MEM FEE000A0h - Pentium - LOCAL APIC - END OF INTERRUPT REGISTER (EOI)
Size: DWORD
Note: write-only
--------H-mFEE000A0--------------------------
MEM FEE000A0h - Pentium - LOCAL APIC - PROCESSOR PRIORITY REGISTER (PPR)
Size: DWORD
Note: read-only
SeeAlso: MEM FEE00000h
--------H-mFEE000B0--------------------------
MEM FEE000B0h - Pentium - LOCAL APIC - RESERVED
SeeAlso: MEM FEE00000h
--------H-mFEE000C0--------------------------
MEM FEE000C0h - Pentium - LOCAL APIC - REMOTE READ REGISTER
Size: DWORD
Note: read-only
--------H-mFEE000D0--------------------------
MEM FEE000D0h - Pentium - LOCAL APIC - LOGICAL DURATION REGISTER (LDR)
Size: DWORD
SeeAlso: MEM FEE00000h
--------H-mFEE000E0--------------------------
MEM FEE000E0h - Pentium - LOCAL APIC - DESTINATION FORMAT REGISTER (DFR)
Size: DWORD
bits 27-0: read-only
bits 31-28: read-write
--------H-mFEE000F0--------------------------
MEM FEE000F0h - Pentium + - LOCAL APIC - SPURIOUS INTERRUPT VECTOR REGISTER
Size: DWORD
Bitfields for Local APIC Spurious Interrupt Vector register:
Bit(s) Description (Table M0126)
63-10 reserved
9 disable focus processor checking during lowest-priority delivery
8 APIC enabled by software
7-4 spurious vector number
3-0 reserved (1)
--------H-mFEE00100--------------------------
MEM FEE00100h - Pentium + - LOCAL APIC - IN-SERVICE REGISTER (ISR)
Size: 128 BYTEs
Note: read-only
SeeAlso: MEM FEE00200h
--------H-mFEE00180--------------------------
MEM FEE00180h - Pentium + - LOCAL APIC - TRIGGER MODE REGISTER (TMR)
Size: 128 BYTEs
Note: read-only
SeeAlso: MEM FEE00000h
--------H-mFEE00200--------------------------
MEM FEE00200h - Pentium + - LOCAL APIC - INTERRUPT REQUEST REGISTER (IRR)
Size: 128 BYTEs
Note: read-only
SeeAlso: MEM FEE00100h
--------H-mFEE00280--------------------------
MEM FEE00280h - Pentium + - LOCAL APIC - ERROR STATUS REGISTER
Size: DWORD
Note: read-only
Bitfields for Pentium APIC error status register:
Bit(s) Description (Table M0120)
0 send checksum error
1 receive checksum error
2 send accept error
3 receive accept error
4 reserved
5 send illegal vector
6 receive illegal vector
7 illegal register address
31-8 reserved
--------H-mFEE00300--------------------------
MEM FEE00300h - Pentium + - LOCAL APIC - INTERRUPT COMMAND REGISTER (ICR)
Size: DWORD
Note: this is the low half of the 64-bit ICR
SeeAlso: MEM FEE00310h,#M0121
Bitfields for Pentium APIC Interrupt Command Register:
Bit(s) Description (Table M0121)
7-0 interrupt vector number
10-8 delivery mode (see #M0122)
11 destination mode
12 delivery status (read-only)
1 = transfer pending
13 reserved
14 level (0 = INIT Level Deassert message, 1 = anything else)
15 trigger mode (1)
17-16 remote read status (read-only)
19-18 destination shorthand
00 as specified by destination field
01 self
10 all including self
11 all except self
55-20 reserved
63-56 destination for interrupt request or message
SeeAlso: #M0124
(Table M0122)
Values for Pentium APIC delivery mode:
000b fixed
001b lowest-priority
010b SMI
011b remote read
100b NMI
101b INIT
110b start up
111b reserved
SeeAlso: #M0121
--------H-mFEE00310--------------------------
MEM FEE00310h - Pentium + - LOCAL APIC - INTERRUPT COMMAND REGISTER (ICR)
Size: DWORD
Note: this is the high half of the 64-bit ICR
SeeAlso: MEM FEE00300h,#M0121
--------H-mFEE00320--------------------------
MEM FEE00320h - Pentium + - LOCAL APIC - LOCAL VECTOR TABLE ENTRY 0 (TIMER)
Size: DWORD
SeeAlso: MEM FEE00350h,MEM FEE00370h,MEM FEE003E0h,INT 70h
Bitfields for Pentium APIC timer local vector entry:
Bit(s) Description (Table M0123)
7-0 interrupt vector number
11-8 reserved
12 delivery status (read-only)
1 = interrupt being sent to APIC
15-13 reserved
16 interrupt delivery disabled
17 timer mode (0=one-shot, 1=periodic)
31-18 reserved
SeeAlso: #M0125,#M0124
--------H-mFEE00330--------------------------
MEM FEE00330h - Pentium + - LOCAL APIC - RESERVED
SeeAlso: MEM FEE00000h
--------H-mFEE00340--------------------------
MEM FEE00340h - Pentium + - LOCAL APIC - RESERVED
SeeAlso: MEM FEE00000h
--------H-mFEE00350--------------------------
MEM FEE00350h - Pentium + - LOCAL APIC - LOCAL VECTOR TABLE ENTRY 1 (LINT0)
Size: DWORD
SeeAlso: MEM FEE00320h,MEM FEE00360h
Bitfields for Pentium APIC LINTx local vector entry:
Bit(s) Description (Table M0124)
7-0 interrupt vector number
10-8 delivery mode
000 fixed
100 NMI
111 external interrupt (8259A-compatibility)
11 reserved
12 delivery status (read-only)
1 = interrupt being sent to APIC
13 interrupt pin is active low
14 remote IRR
15 trigger mode
0 edge-sensitive
1 level-sensitive
16 interrupt delivery disabled
31-17 reserved
SeeAlso: #M0123
--------H-mFEE00360--------------------------
MEM FEE00360h - Pentium + - LOCAL APIC - LOCAL VECTOR TABLE ENTRY 2 (LINT1)
Size: DWORD
SeeAlso: MEM FEE00350h,MEM FEE00370h,#M0124
--------H-mFEE00370--------------------------
MEM FEE00370h - Pentium + - LOCAL APIC - LOCAL VECTOR TABLE ENTRY 3 (Error)
Size: DWORD
SeeAlso: MEM FEE00320h,MEM FEE00370h
--------H-mFEE00380--------------------------
MEM FEE00380h - Pentium + - LOCAL APIC - INITIAL COUNT REGISTER (ICR) TIMER
Size: DWORD
Desc: timer start value, which together with the Divide Configuration
Register also determines its period when periodic mode has been
selected
SeeAlso: MEM FEE00000h,MEM FEE00390h
--------H-mFEE00390--------------------------
MEM FEE00390h - Pentium + - LOCAL APIC - CURRENT COUNT REGISTER (CCR) TIMER
Size: DWORD
Desc: current timer count; when this value reaches zero, an interrupt is
generated
Note: read-only
SeeAlso: MEM FEE00380h
--------H-mFEE003A0--------------------------
MEM FEE003A0h - Pentium - LOCAL APIC - RESERVED
SeeAlso: MEM FEE00000h
--------H-mFEE003B0--------------------------
MEM FEE003B0h - Pentium - LOCAL APIC - RESERVED
SeeAlso: MEM FEE00000h
--------H-mFEE003C0--------------------------
MEM FEE003C0h - Pentium - LOCAL APIC - RESERVED
SeeAlso: MEM FEE00000h
--------H-mFEE003D0--------------------------
MEM FEE003D0h - Pentium - LOCAL APIC - RESERVED
SeeAlso: MEM FEE00000h
--------H-mFEE003E0--------------------------
MEM FEE003E0h - Pentium + - LOCAL APIC - TIMER DIVIDE CONFIGURATION REGISTER
Size: DWORD
SeeAlso: MEM FEE00000h,MEM FEE00320h
Bitfields for Pentium (and later) APIC timer divide configuration:
Bit(s) Description (Table M0125)
31-4 reserved
3,1,0 divisor
000 divide by 2
001 by 4
010 by 8
...
110 by 128
111 by 1
2 zero (0)
Note: the divisor determines the timer's time base relative to the processor
clock
SeeAlso: #M0123
----------MFFFF0010--------------------------
MEM FFFFh:0010h - HIGH MEMORY AREA (HMA)
Size: 65520 BYTEs
--------!---CONTRIBUTORS---------------------
Robin Walker <rdhw@cus.cam.ac.uk> ORIGINAL FILE
Wim Osterholt <wim@djo.wtm.tudelft.nl> or Wim Osterholt 2:512/56
EHD floppy = 'KEGAN 4.0M Floppy Drive Controller.',
'ACME FX4-K7tb2 v:2.5 11/5/91'
Stanley Appel <appel@stack.urc.tue.nl>
Matthias Paul <Matthias.Paul@post.rwth-aachen.de>
--------!---Admin----------------------------
Highest Table Number = M0134
--------!---FILELIST-------------------------
Please redistribute all of the files comprising the interrupt list (listed at
the beginning of the list and in INTERRUP.1ST) unmodified as a group, in a
quartet of archives named INTER61A through INTER61D (preferably the original
authenticated PKZIP archives), and the utility and hypertext programs in a
pair of additional archives called INTER61E.ZIP and INTER61F.ZIP.
Copyright (c) 1989-1999,2000 Ralf Brown
--------!---CONTACT_INFO---------------------
E-mail: ralf@pobox.com (currently forwards to ralf@telerama.lm.com)