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-=-=-=-=-=-=-
- *****************************************************************
- *
- RUN Command Handler *
- *
- *****************************************************************
- *
- DOS's RUN command loads an Integer or Applesoft file and *
- then attempts to execute it. If the specified file is not on *
- the disk, a file-not-found error message is printed. If the *
- file type code of the specified file is not compatible with *
- the currently active language, the computer attempts to select *
- the correct basic before LOADing the file. *
- *
- *****************************************************************
- On entry - CUMLOPTN ($AA65) has been updated
- to reflect parsed option words.
- (Only volume (VOLPRSD), drive (DRVPRSD)
- and slot (SLOTPRSD) parameters are
- allowed with the DOS RUN command.)
- - the validity of the options issued
- with the command (and their numeric
- values) have been checked.
- - if a legal file name was issued, it has
- been parsed & placed in the primary file
- name buffer (PRIMFNBF, $AA75).
- if no filename was issued with the RUN
- comand, then execution doesn't get this far.
- Instead, the DOS interpreter preceives the
- "RUN" as a BASIC command & therefore sends
- it along to the basic interpreter where it
- attempts to RUN a program currently in memory.
(A4D1)
CMDRUN LDA ACTBSFLG ;Check which basic is current.
;(Int=$00, A(ROM)=$40, A(RAM0=$80)
(A4D4) BEQ LOAD4RUN ;Branch if using integer.
(A4D6) STA RUNTRUPT ;Set the RUN intercept flag to siganl that
;we are about to interrupt the RUN command
;to do a LOAD. ($40=A(ROM), $80=A(RAM).)
- GO LOAD THE PROGRAM.
- NOTE: THE "JSR" INSTRUCTION SHOWN BELOW IS
- ACTUALLY A PLACEBO because after the file is
- loaded, execution goes into basic and then
- re-enters DOS. Once DOS gets its mitts back
- into things, the RUNTRUPT flag is tested, THE
- STACK IS RESET and then execution flows to the
- next instruction (at RUNFPINT, $A4DC)).
(A4D9)
LOAD4RUN JSR CMDLOAD
(A413)
CMDLOAD .
.
(See dis'mbly below.)
.
.
(RTS)
(A4DC)
RUNFPINT JSR CRVIADOS
* Print a carriage return via DOS and the monitor.
(9FC8)
CRVIADOS LDA #$8D ;Carriage return.
(9FCA) JMP GODSPLY ;Print char thru true output handler.
------------
(9FC5)
GODSPLY JMP (CSW) ;CSW points to the true output handler (normally COUT1).
------------
(FDF0)
COUT1 .
.
(Monitor ROM's screen output routine.)
(See dis'mbly in APPLE II REFERENCE MANUAL.)
.
.
(RTS)
(A4DF) JSR INITIOHK
* Initialize the I/O hooks so that DOS
* intercepts all input and output. For
* instance, if a routine encounters a
* "COUT JMP (CSW)" then execution will
* actually flow to DOS's output handler
* routine (OPUTINCP, $9EBD). Similarly,
* any routine that refers to "RDKEY JMP (KSW)"
* will actually jump to DOS's input routine
* (INPTINCP, $9E81).
* The true (ie. normal) hooks are saved, ex:
* KSW: KEYIN --> KSWTRUE: KEYIN.
* CSW: COUT1 --> CSWTRUE: COUT1.
* The intercepts are then set as follows:
* ADINPTCP: INPTINCP --> KSW: INPTINCP.
* ADOPUTCP: OPUTINCP --> CSW: OPUTINCP.
* Check if input hook needs to be reset.
(A851)
INITIOHK LDA KSW+1
CMP ADINPTCP+1
(A856) BEQ CKOUTHK ;Input hook already points to DOS's
;input handler so go check output hook.
* Reset input hook to point to DOS.
(A858) STA KSWTRUE+1 ;KSW: KEYIN --> KSWTRUE: KEYIN.
LDA KSW
STA KSWTRUE
LDA ADINPTCP ;ADINPTCP: INPTINCP --> KSW: INPTINCP.
STA KSW
LDA ADINPTCP+1
(A868) STA KSW+1
* Check if output hook needs to be reset.
(A86A)
CKOUTHK LDA CSW+1
CMP ADOPUTCP+1
(A86F) BEQ SETHKRTN ;Output hook already points to DOS's
;output handler routine, so exit.
* Reset output hook to point to DOS.
(A871) STA CSWTRUE+1 ;CSW: COUT1 --> CSWTRUE: COUT1.
LDA CSW
STA CSWTRUE
LDA ADOPUTCP ;ADOPUTCP: OPUTINCP --> CSW: OPUTINCP.
STA CSW
LDA ADOPUTCP+1
STA CSW+1
SETHKRTN RTS
(A883)
(A4E2) JMP (RUNTRY) ;Go execute the program.
------------ ;(RUNTRY points to RUNFPROM if using A(ROM)
;or RUNFPRAM if using A(RAM).)
(A4FC)
RUNFPROM JSR SETZPTRS
(D665)
SETZPTRS JSR SETXTPT
* Set TXTPTR to approximate beginning of
* program (ie. TXTPTR: TXTTAB-1, normally $800).
(D697)
SETXTPT CLC
LDA TXTTAB ;Add negative 1 to low byte.
ADC #$FF
STA TXTPTR
LDA TXTTAB+1 ;Add zero to hi byte if carry set.
ADC #$FF ;Else add neg 1 to hi byte if carry clr.
STA TXTPTR+1
(D6A4) RTS
* Simulate a "CLEAR" statement.
* (Reset variable & string pointers.)
(D668) LDA #0
CLEAR BNE CLRTS
CLEARC LDA MEMSIZ
LDY MEMSIZ+1
STA FRETOP ;FRETOP: MEMSIZ
STY FRETOP+1
LDA VARTAB ;ARYTAB: VARTAB
LDY VARTAB+1
STA ARYTAB
STY ARYTAB+1
STA STREND ;STREND: VARTAB
STY STREND+1
(D680) JSR RESTORE
* Simulate a RESTORE statement. That is, reset
* the pointer which points to bytes in DATA
* statement (DATPTR: TXTTAB-1).
(D849)
RESTORE SEC
LDA TXTTAB
SBC #1
LDY TXTTAB+1
BCS SETDA
DEY
SETDA STA DATPTR ;Otherwise, points to addr
STY DATPTR+1 ;of current DATA statement.
(D857) RTS
* Re-initialize stk while preserving return addr.
(D683)
STKINI LDX #<TEMPST ;Set pointer to descriptor
STX TEMPPT ;for garbage collection.
PLA ;Save return address.
TAY
PLA
LDX #$F8 ;Adjust stack pointer to $1F8 in order to
(D68C) TXS ;leave enough room for links & line # bytes.
;(Actually reserves more space than needed.
;$1FB would have done just fine.)
(D68D) PHA ;Retrieve return address & put it back on stack.
TYA
PHA
LDA #0 ;Defeat any "CONT" statement.
STA OLDTEXT+1 ;Otherwise pts to last byte (an $00) of
STA SUBFLG ;line just executed.
CLRTS RTS
(D696)
(A4FF) STA PROMPT ;Zero out the prompt
STA ERRFLG ;and on-error flag.
(A503) JMP NEWSTT ;Jump back into APPLESOFT.
------------
(D7D2)
NEWSTT .
.
- collect & execute the program statements.
.
.
- Eventually the RUN command is exited via the
RESTART ($D43C) routine. The applicable version
of the RESTART routine that is used is shown in
the disassembly entitled "DOSWARMSTART".
===============================================================================================================================
- *****************************************************************
- *
- LOAD Command Handler *
- *
- ----------------------------------------------------------------*
- *
- DOS's LOAD command loads an Integer, Applesoft or A-type *
- file from the disk. Volume, drive and slot parameters are *
- optional. If no file name is issued with the command, DOS *
- interprets the "LOAD" as a basic command and therefore passes *
- it along to basic where it is used to load a file from a *
- cassette tape. *
- *
- A-type files are (like Applesoft files) represented in *
- the catalog by the character "A". Their hexadecimal file type *
- code is however different ($A0 = locked A-type, $20 = unlocked *
- A-type). No formal structure of an A-type file has been *
- defined. Some authors modify DOS to generate files with a *
- unique structure and then designate them as A-type files. This*
- technique is often used as part of a protection scheme or to *
- serve some specialized purpose (ex. WORD HANDLER files from *
- Advanced Logic Systems). *
- *
- Execution pattern: *
- The execution pattern of the load command is difficult to *
- follow because: *
- 1) It is dependent upon the nature of the caller. *
- 2) Execution automatically jumps into BASIC once the *
- program is in memory. *
- After closing all files (except an active EXEC file), the *
- common file manager command handler code (HNDLCMD, $A416) is *
- called to assign a free DOS buffer to the named file and to *
- customize the FM parameter list. The file manager (FILEMGR, *
- $AB06) is then called to open the file by reading its first *
- track/sector list into the T/S list buffer. (Failure to locate*
- the named file results in a file-not-found error.) *
- If the file just opened is NOT an Integer ($01), Applesoft*
- ($02) or A-type ($20) file, a type mismatch error message is *
- printed. Otherwise, the active basic flag (ACTBSFLG, $AAB6) *
- is checked to see which basic is active. When Integer is in *
- effect, a branch is made to integer basic's load routine *
- (LODINTGR, $A450). If A(ROM) or A(RAM) are being used, the *
- accummulator is loaded with the number "2" and SELCTBSC *
- ($A4B1) is called to check if an Applesoft file was found. If *
- a different file type was located, the computer assumes that *
- the integer language is required and execution jumps to the *
- INT command to switch languages. (Note that this may *
- eventually cause a crash if an A-type file was found.) If an *
- Applesoft file was found, execution returns to the main load *
- routine at $A42D. *
- The length of the program is then read from the first two *
- bytes of the file and stored in the FM parameter list at *
- LENADRBF ($AA60). Next a check is made to see if enough free *
- memory space is available to accommodate the program. If *
- (LENADRBF) + (TXTTAB) > = (MEMSIZ), a program-too-large error *
- message is generated. If enough space is available, the *
- end-of-program (PRGEND, $AF) and start-of-variable-space *
- (VARTAB, $67) pointers are set. *
- The file is then read into free memory at the location *
- defined by the start-of-program pointer (TXXTTAB, $67). As *
- the program is read in, LENADRBF is used as a byte counter. *
- Once the entire program is in place, the file is closed and *
- the I/O hooks are reset to point to DOS. Execution then jumps *
- to the address pointed to by RLOCNTRY ($9D60). *
- When Applesoft is being used, RLOCNTRY points to Applesoft*
- basic's relocation handler (SETLINKS, $D4F2). It is this *
- routine that reconfigures Applesoft programs and enables them *
- to be relocatable. Unfortunately, SETLINKS also has a darker *
- side to its personality. Because it clears all variable, *
- string and data pointers, it prevents Applesoft programs from *
- being "chainable." *
- After all of the Applesoft program's line links are *
- adjusted to their new location, execution flows into Applesoft *
- basic's RESTART routine ($D43C). However, the pattern of *
- program flow depends upon the nature of the caller. If the *
- RUN command was interrupted to do a LOAD, the run interrupt *
- flag (RUNTRUPT, $AAB7) is turned off and execution jumps to *
- RUNFPINT ($A4DC) to complete the RUN command. If the LOAD was *
- not called from the RUN command, a normal RESTART is done. *
- (See formatted disassembly given in the file titled *
- DOSWARMSTART.) *
- *
- Note that the start-of-program pointer (TXTTAB, $67-$68) *
- defines the load address. Normally, this pointer contains an *
- $801. However, by simply zapping TXTTAB with a different value*
- prior to issuing the LOAD command, an Applesoft program can be *
- read into a non-standard location. This techniques is often *
- used to load a program above the graphics screen. *
- The indirect jump at $A44D represents an opportunity to *
- divert the load routine to a user-installed patch. For *
- instance, you can simulate an Applesoft version of the CHAIN *
- command by pointing RLOCNTRY at a patch that adjusts program *
- line pointers and perserves all variables. *
- If the exact file structure is known, it is sometimes a *
- simple matter to modify the LOAD routine to accommodate certain*
- commercial programs that use A-type files. *
- *
- *****************************************************************
- On entry - CUMLOPTN ($AA65) has been updated
- to reflect parsed option words.
- (Only volume (VOLPRSD), drive (DRVPRSD)
- and slot (SLOTPRSD) parameters are
- allowed with the DOS LOAD command.)
- - the validity of the options issued
- with the command (and their numeric
- values) have been checked.
- - if a legal file name was issued, it has
- been parsed & placed in the primary file
- name buffer (PRIMFNBF, $AA75).
- if no filename was issued with the LOAD
- comand, then execution doesn't get this far.
- Instead, the DOS interpreter preceives the
- "LOAD" as a BASIC command & therefore sends
- it along to the basic interpreter where it
- is used to load the next sequential program
- from a CASSETTE tape.
(A413)
CMDLOAD JSR CLOSEALL
* CLOSE ALL FILES (EXCEPT AN ACTIVE EXEC FILE).
(A316)
CLOSEALL JSR GETFNBF1 ;Enter here when direct call or if 1rst char
;in primary filename field was a space.
* Put address of 1rst DOS name buffer
* (chain) in the A3L/H pointer.
(A792)
GETFNBF1 LDA ADOSFNB1 ;First link to chain of DOS buffers
LDX ADOSFNB1+1 ;(ie. pt to 1rst filename buffer in chain).
(A798) BNE SETNXPTR ;ALWAYS.
(A7A4)
SETNXPTR STX A3L+1 ;Put addr of 1rst filename buffer in ptr
STA A3L ;(ie. highest name buffer in chain).
TXA ;Get hi-byte of addr back in (a).
GETNXRTN RTS
(A7A9)
(A319) BNE CKIFEXEC ;ALWAYS.
(A31B)
CHKNXBUF JSR GETNXBUF
* Get addr of next filename buffer in chain
* from chain pointers buffer offset 37 & 36
* bytes from 1rst char of present filename
* buffer.
(A79A)
GETNXBUF LDY #37 ;Point ptr at chain buffer.
LDA (A3L),Y ;Pick up hi byte of addr of nxt filename buffer.
BEQ GETNXRTN ;If hi-byte is 0 then link zeroed out.
TAX ;Save hi-byte in (x).
DEY ;Pick up low-byte.
LDA (A3L),Y
SETNXPTR STX A3L+1 ;Stick addr of filename buffer in ptr.
STA A3L
TXA ;Condition z-flg in relation to hi byte .
GETNXRTN RTS
(A7A9)
(A31E) BEQ CLOSERTS ;Link zeroed out, so now all files closed.
(A320) ;Exit CLOSEALL via this route.
CKIFEXEC JSR CKEXCBUF
* Check if current filename buffer
* belongs to an EXEC file.
(A7AF)
CKEXCBUF LDA EXECFLAG ;Check to see if EXECing.
BEQ NOTEXCBF ;No sweat - not running exec file.
LDA EXECBUFF ;We are EXECing, there4 chk if addr of
CMP A3L ;current filename buffer same as that
BNE CKEXCRTN ;for buffer belonging to EXEC.
LDA EXECBUFF+1 ;Maybe - low-bytes matched, now chk hi bytes.
CMP A3L+1
BEQ CKEXCRTN ;Exec buffer = current buffer.
NOTEXCBF DEX ;Not EXECing, there4 reduce (X) to make sure z-flag off.
(A7C2) ;(P.S. (x) was orig conditioned to a large non-zero
;value on entry to GETFNBF1. There4, if now DEX then
(A7C3) ;can be sure z-flag will be off.)
CKEXCRTN RTS ;If execing, rtn with z-flag on.
(A323) BEQ CHKNXBUF ;EXEC WAS ACTIVE SO DON'T CLOSE ITS BUFFER
;OUT OR WILL END UP IN NEVER-NEVER-LAND.
;After all, don't want to close buffer
;if we are using it to exec (ie. would
;be like burying ourselves alive)!!!
(A325) JSR GETFNBY1 ;Get first char of filename from buf in chain.
* Get first byte from DOS name buffer.
(A7AA)
GETFNBY1 LDY #0 ;Buffer is free if 1rst byte = $00.
LDA (A3L),Y ;If buffer is occuppied, the 1rst byte
(A7AE) RTS ;in buf = 1rst char in name of file which
;owns the buffer.
(A328) BEQ CHKNXBUF ;This file is already closed, so go back
;to close rest of files.
(A32A) JSR CLOSEONE
* CLOSE THE OPEN FILE.
(A2FC)
CLOSEONE JSR CKEXCBUF
* Check if current filename buffer
* belongs to an EXEC file.
(A7AF)
CKEXCBUF LDA EXECFLAG ;Check to see if EXECing.
BEQ NOTEXCBF ;No sweat - not running exec file.
LDA EXECBUFF ;We are EXECing, there4 chk if addr of
CMP A3L ;current filename buffer same as that
BNE CKEXCRTN ;for buffer belonging to EXEC.
(A7BB) LDA EXECBUFF+1 ;Maybe - low-bytes matched,
;so now check hi bytes.
(A7BE) CMP A3L+1
BEQ CKEXCRTN ;Exec buffer = current buffer.
NOTEXCBF DEX ;Not EXECing, DEX to make sure z-flag off.
(A7C2) ;(P.S. (x) orig conditioned to a large
;non-zero value on entry to GETFNBF1.
;There4, if now DEX then can be sure
(A7C3) ;z-flag will be off.)
CKEXCRTN RTS ;Exit with z-flag = 1 if execing.
; = 0 if not execing.
(A2FF) BNE FREEBUFF ;ALWAYS BRANCH IF CLOSEONE IS ACCESSED VIA CLOSEALL.
LDA #0 ;Shut exec flag off.
(A303) STA EXECFLAG ;NOTE: THIS INSTRUCTION IS NEVER CARRIED
;OUT IF ACCESSED VIA CLOSEALL. (An active exec file
;was already detected and skipped by the "BEQ CHKNXBUF"
(A306) ;instruction at $A323.)
FREEBUFF LDY #0
TYA ;Free up the DOS buffer by poking a $00 in the
STA (A3L),Y ;1rst byte of the filename field.
(A30B) JSR BUFS2PRM
* GET addresses of the DOS buffers from chain
* buffer & put them in FM parameter list.
(A74E)
BUFS2PRM LDY #30 ;Get addresses of FM Work buffer,
ADRINPRM LDA (A3L),Y ;T/S list buffer, Data sec buffer and
STA WRKBUFFM-30,Y ;NEXT filename buf from chain ptr
INY ;buf & put them in FM parameter list.
CPY #38 ;(P.S. addr of NEXT filename buffer not
BNE ADRINPRM ;used by DOS.)
(A75A) RTS
(A30E) LDA #2 ;Stick opcode for CLOSE function
STA OPCODEFM ;in the FM parameter list.
(A313) JMP FMDRIVER ;Get ready to do the function.
------------
(A6A8)
FMDRIVER JSR FILEMGR ;Call the file manager
;to execute the CLOSE function.
(AB06)
FILEMGR TSX ;Save stk pointer so can rtn to caller.
STX STKSAV
(AB0A) JSR RSTRFMWA ;Copy FM work buffer (in DOS chain)
;to FM work area (not in buffer chain).
(AE6A)
RSTRFMWA JSR SELWKBUF ;Find FM work buf.
* Get adr of FM wrk buf
* from FM parm list &
* put it in A4L/H ptr.
(AF08)
SELWKBUF LDA #0
(AF0A) BEQ PT2FMBUF
(AF12)
PT2FMBUF LDA WRKBUFFM,X
STA A4L
LDA WRKBUFFM+1,X
STA A4L+1
(AF1C) RTS
(AE6D) LDY #0 ;Zero-out return code
(AE6F) STY RTNCODFM ;in FM parm list to
(AE72) ;signal no errors.
STORFMWK LDA (A4L),Y ;Copy FM work buf
STA FMWKAREA,Y ;(in chain) to FM
INY ;wrk area (not in
CPY #45 ;DOS buf chain).
BNE STORFMWK
CLC ;Why?????
(AE7D) RTS
(AB0D) LDA OPCODEFM ;Chk if opcode is legal.
CMP #13 ;(Must be less than 13.)
BCS TOERROP ;Opcode too large, go to range error.
ASL ;Double val of opcode & get addr of
TAX ;appropriate function handler from table.
LDA FMFUNCTB+1,X ;Stick adr on stack (hi byte first)
PHA ;& then do a "stack jump" to the appropriate
LDA FMFUNCTB,X ;function handler.
PHA
(AB1E) RTS
(AC06)
FNCLOSE .
.
.
(See dis'mbly of CLOSE function.)
.
.
- if necessary, free up any sectors that
were previously allocated to the file
but not needed.
- also updates the file size, fixes up
links & updates data, VTOC, T/S list
& directory sectors if necessary.
.
.
(RTS)
============
TOERROP JMP RNGERROP ;To $B363 - see dis'mbly of errors.
(AB1F) ------------
* Return here after doing the CLOSE function
* (Cause after @ function is done, use stack
* to get back to original caller.)
(A6AB)
AFTRFUNC BCC FMDRVRTN ;(c) = 0 = no errors.
LDA RTNCODFM ;Get error code from FM parameter list.
CMP #5 ;End-of-data error?
(A6B2) BEQ TOAPPTCH ;Yes - got a zeroed-out T/S link or a
;zeroed-out data pair values listed in
;a T/S list. (Not applicable to the
;close function.)
(A6B4) JMP OTHRERR ;No. See dis'mbly of errors.
------------
(A6C3)
FMDRVRTN RTS
(A32D) JMP CLOSEALL ;Goes to next instruction (CLOSERTS) via CLOSEALL.
------------
(A330)
CLOSERTS RTS
============
(A416)
OPENLOAD JSR HNDLCMD ;Go open the file.
* OPEN THE FILE.
* On entry from LOAD command, LENPRSD = 0.
*
* Common file manager command handler code.
(A2A8)
HNDLCMD LDA #1 ;1 = open opcode.
HNDLCMD1 STA TEMPBYT ;Store opcode in temporary location.
LDA LENPRSD ;Get L-parameter from parsed table.
BNE SAVLENFM ;Was a non-zero L-parm issued with cmd?
LDA LENPRSD+1
BNE SAVLENFM
LDA #1 ;Length was 0 so make it 1 instead.
STA LENPRSD
SAVLENFM LDA LENPRSD ;Put length in FM parm list.
STA RECLENFM
LDA LENPRSD+1
STA RECLENFM+1
CLSLOCBF JSR CMDCLOSE ;Close file if it's already open.
(A2C8)
(A2EA)
CMDCLOSE .
.
(See dis'mbly of CMDCLOSE .)
.
.
- Because CLOSEALL was just used to close all
open files, this call to CMDCLOSE is only
used for its reference to GETBUFF to
locate a free DOS buffer.
.
.
- If necessary, the CLOSE FUNCTION updates the data
sector, T/S list sector & the VTOC. It also fixes
up links in the directory sectors and updates the
file size if needed.
.
.
(RTS)
(A2CB) LDA A5L+1 ;Hi byte of A5L/H pointer which points at the highest
;numbered (lowest in memory) free DOS name buffer (in chain).
(A2CD) BNE SAVFNPTR ;Branch if found a free buffer.
(A2CF) JMP NOBUFERR ;Go issue an out-of-buffers message.
------------ ;(See dis'mbly of errors.)
(A2D2)
SAVFNPTR STA A3L+1 ;Reset A3L/H to point at DOS buffer that we
LDA A5L ;will use for file name field buffer (chain).
STA A3L
(A2D8) JSR CPYPFN
* NOTE: This (re)assigns a DOS buffer to the file
* we want to OPEN/LOAD. The buffer may or may not
* be the same one that was just released by the
* CLOSE cmd above. The highest numbered (lowest in
* memory) free DOS buffer is used.
(A743)
CPYPFN LDY #29 ;30 bytes to copy (0 to 29).
CPYPRIM LDA PRIMFNBF,Y ;Copy the name of the file wanted from
STA (A3L),Y ;the primary filename buffer into the
DEY ;filename field buffer (in DOS chain).
BPL CPYRIM ;More chars to get.
(A74D) RTS
(A2DB) JSR BUFS2PRM
* Get addresses of the various DOS buffers from the
* chain buffer & put them in the FM parameter list.
(A74E)
BUFS2PRM LDY #30 ;Get addr of FM work buf, T/S list
ADRINPRM LDA (A3L),Y ;buf, data sector buf & next DOS
STA WRKBUFFM-30,Y ;filename buf from chain
INY ;pointer buffer & put them in FM parm list.
CPY #38 ;(P.S. Adr of next DOS file name buf is
BNE ADRINPRM ;not used by DOS.)
(A75A) RTS
(A2DE) JSR CPY2PARM
* Put volume, drive, & slot values plus the
* address of the primary filename buffer
* in the FM parameter list.
(A71A)
CPY2PARM LDA VOLPRSD ;From parsed table.
STA VOLFM
LDA DRVPRSD ;From parsed table.
STA DRVFM
LDA SLOTPRSD ;From parsed table.
STA SLOTFM
LDA ADRPFNBF ;Get the adr of the primary file
STA FNAMBUFM ;name buf from the constants tbl
LDA ADRPFNBF+1 ;and put it in the FM parm list.
STA FNAMBUFM+1
LDA A3L ;Save adr of current DOS file name
STA CURFNADR ;buf in table of DOS variables.
LDA A3L+1
STA CURFNADR+1
(A742) RTS
(A2E1) LDA TEMPBYT ;Get open opcode back from temporary buffer
STA OPCODEFM ;and put it in the FM parameter list.
(A2E7) JMP FMDRIVER
------------
* USE THE FILE MANAGER DRIVER
* TO DO THE OPEN FUNCTION.
(A6A8)
FMDRIVER JSR FILEMGR ;Call the file manager to do the function.
* File manager proper.
(AB06)
FILEMGR TSX ;Save stk pointer so can later rtn to caller of FM.
STX STKSAV
(AB0A) JSR RSTRFMWA
* Copy FM work buf (in DOS chain) to
* FM work area (not in DOS chain).
(AE6A)
RSTRFMWA JSR SELWKBUF ;Point A4L/H at FM work buf.
* Get addr of FM work buff from
* the FM parm list & put it in
* the A4L/H pointer.
(AF08)
SELWKBUF LDX #0 ;Offset to select
;work buffer.
(AF0A) BEQ PT2FMBUF ;ALWAYS.
(AF12)
PT2FMBUF LDA WRKBUFFM,X
STA A4L
LDA WRKBUFFM+1,X
STA A4L+1
(AF1C) RTS
(AE6D) LDY #0 ;Zero out return code in FM parm list to
STY RTNCODFM ;signal no errors as default condition.
STORFMWK LDA (A4L),Y ;Copy FM work buf to FM work area.
STA FMWKAREA,Y
INY
CPY #45 ;45 bytes to copy (0 to 44).
BNE STORFMWK
CLC ;WHY?????
(AE7D) RTS
(AB0D) LDA OPCODEFM ;Check if opcode is legal.
CMP #13 ;(Must be less than 13.)
BCS TOERROP ;Opcode too large so got range error.
ASL ;Double val of opcode & put it in (x)
TAX ;so it indexes tables of adrs.
LDA FMFUNCTB+1,X ;Stick adr of appropriate function
PHA ;handler on stack (hi byte first).
LDA FMFUNCTB,X
PHA
(AB1E) RTS ;DO STACK JUMP TO FUNCTION ENTRY POINT.
.
.
(AB22)
FNOPEN .
.
(See dis'mbly of OPEN function.)
.
.
- uses part of COMNOPEN routine.
- reads in VTOC to get link to 1rst directory.
- reads directory secs in & looks for file
description entry with matching filename.
- if matching name found, reads in the
1rst T/S list sector belonging to the file.
- if no match found, issues a "file not found"
message cause LOAD cmd can't create a new file.
- reads T/S list back into T/S list buf.
.
.
(RTS)
============
TOERROP JMP RNGERROP ;Go handle range error.
(AB1F) ------------ ;(See dis'mbly of errors.)
* Return here after doing the OPEN FUNCTION.
* (Cause after @ function is done, use stack
* to get back to the original caller.)
(A6AB)
AFTRFUNC BCC FMDRVRTN ;(c) = 0 = no errors.
LDA RTNCODFM ;Get error code from FM parameter list.
CMP #5 ;End-of-data error?
(A6B2) BEQ TOAPPTCH ;Yes - got a zeroed-out T/S link or a
;zeroed-out data pair values listed in
;a T/S list. (Not applicable to the
;open function.)
(A6B4) JMP OTHRERR ;No. See dis'mbly of errors.
------------
(A6C3)
FMDRVRTN RTS
- Restrict LOAD command to Applesoft ($02),
- Integer ($01) or A-type ($20) files.
(A419) LDA #$23
AND FILTYPFM ;Type found (via OPEN function).
BEQ TOTYPMIS ;Err - not one of the above file types.
STA FILTYPFM ;Save type wanted in FM parameter list.
(A423) LDA ACTBSFLG ;Check which basic is active:
; INT=$00, FP=$40 & A(RAM)=$80.
(A426) BEQ LODINTGR ;Branch if Integer is active language.
;(See linear disassembly.)
(A428) LDA #2 ;Code for Applesoft (ie. FP).
(A42A) JSR SELCTBSC ;Check if type wanted is Applesoft.
* Check if desired basic is up or not.
* Switch basic if necessary.
(A4B1)
SELCTBSC CMP FILTYPFM ;Basic wanted = basic found?
(A4B4) BEQ SELBSRTN ;Yes - basic wanted is active.
* Type of file wanted is not compatible
* with current active language.
(A4B6) LDX NDX2CMD ;Save index to current command in case
(A4B9) STX NEXTCMD ;we are using integer & must load integer
;file called "APPLESOFT" in order to load A(RAM).
(A4BC) LSR ;Shift type wanted in order to see which basic to switch into.
BEQ SWTCH2FP
(A4BF) JMP CMDINT ;Switch from FP to Integer.
------------
* Switching from Integer to Applesoft
* so copy name of file from primary
* to secondary name buffer in case we
* have to use RAM-based Applesoft.
(A4C2)
SWTCH2FP LDX #29 ;30 bytes to copy (0 to 29).
PRIM2SND LDA PRIMFNBF,X ;Get byte from primary.
STA SCNDFNBF,X ;Copy it to secondary.
DEX
(A4CB) BPL PRIM2SND ;Branch if more bytes to copy.
* Execute the FP command.
(A4CD) JMP CMDFP ;See dis'mbly of FP command.
---------
* Type of basic required (ie. compatible
* with file type wanted) is currently active.
(A4D0)
SELBSRTN RTS ;Desired basic was active.
(A42D) JSR RDADRLEN
* READ THE LENGTH OF THE FP PRGM
* FROM THE FIRST TWO BYTES OF THE FILE.
(A47A)
RDADRLEN LDA ADLENADR ;Get adr of two-byte input buffer (LENADRBF,
STA CURIOBUF ;$AA60) from relocatable constants table and
LDA ADLENADR+1 ;designate it as the I/O buffer in the FM
STA CURIOBUF+1 ;parameter list.
LDA #0 ;Designate length to read as 2 bytes
STA LEN2RDWR+1 ;(ie. want to read load length which is
LDA #2 ;stored as the 1rst 2 bytes of the file).
STA LEN2RDWR
LDA #3 ;Set FM parm list to read a range of bytes.
STA OPCODEFM
LDA #2
STA SUBCODFM
(A49A) JSR FMDRIVER
* USE THE FILE MANAGER DRIVER
* TO READ IN THE LOAD LENGTH.
(A6A8)
FMDRIVER JSR FILEMGR ;Call the file manager to do the function.
* File manager proper.
(AB06)
FILEMGR TSX ;Save the stack pointer so can later
STX STKSAV ;return to the caller of the FM.
(AB0A) JSR RSTRFMWA
* Copy FM work buf (in DOS chain) to
* FM work area (not in DOS chain).
(AE6A)
RSTRFMWA JSR SELWKBUF ;Find FM work buf.
* Get addr of FM
* work buff from
* the FM parm list
* & put it in the
* A4L/H pointer.
(AF08)
SELWKBUF LDX #0
(AF0A) BEQ PT2FMBUF
(AF12)
PT2FMBUF LDA WRKBUFFM,X
STA A4L
LDA WRKBUFFM+1,X
STA A4L+1
(AF1C) RTS
(AE6D) LDY #0 ;Zero out return
(AE6F) STY RTNCODFM ;code in FM parm
;list to assume
;no errors as
(AE72) ;default condition.
STORFMWK LDA (A4L),Y ;Copy FM work buf
STA FMWKAREA,Y ;to FM work area.
INY
CPY #45 ;45 bytes to copy
BNE STORFMWK ;(0 to 44).
CLC ;WHY?????
(AE7D) RTS
(AB0D) LDA OPCODEFM ;Check if opcode is legal.
CMP #13 ;(Must be less than 13.)
BCS TOERROP ;Opcode too large so got range error.
ASL ;Double val of opcode & put it in (x)
TAX ;so it indexes tables of adrs.
LDA FMFUNCTB+1,X ;Stick adr of appropriate function
PHA ;handler on stack (hi byte first).
LDA FMFUNCTB,X
PHA
(AB1E) RTS ;DO STACK JUMP TO FUNCTION ENTRY POINT.
.
.
(AC58)
FNREAD .
.
(See dis'mbly of READ function
and read-a-range (READRNG, $AC96)
subfunction.)
.
.
- reads in first two bytes of file to
get length of file in bytes.
- On entry: LEN2RDWR: 2, FILPTSEC: $FFFF, RELFIRST: 0,
RELASTP1: $7A, RELPREV: 0, RECNMBWA:0,
RECNMBFM: 0, BYTOFFWA: 0, BYTOFFFM: 0,
RECLENFM: 1, RECLENWA 1 and
CURIOBUF = LENADRBF addr (normally $AA62).
.
.
(RTS)
============
TOERROP JMP RNGERROP ;Go handle range error.
(AB1F) ------------ ;(See dis'mbly of errors.)
* Return here after doing the READ FUNCTION.
* (Cause after @ function is done, use stack
* to get back to the original caller.)
* Note that (c) = 0 if a byte from a data sector was
* just read -- even if that byte was a $00.
(A6AB)
AFTRFUNC BCC FMDRVRTN ;(c) = 0 = no errors.
LDA RTNCODFM ;Get error code from FM parameter list.
CMP #5 ;End-of-data error?
(A6B2) BEQ TOAPPTCH ;Yes - got a zeroed-out T/S link or a
;zeroed-out data pair values listed in
;a T/S list.
(A6B4) JMP OTHRERR ;No. See dis'mbly of errors.
TOAPPTCH JMP APNDPTCH ;(See dis'mbly of errors.)
NOP
BK2FMDRV JSR CKIFAPND ;Note: APNDPTCH returns here.
(A6BB)
* Check if using the append command.
(BA69)
CKIFAPND LDX CMDINDEX ;Get command index.
CPX #$1C ;Are we APPENDing?
BEQ RTNCKAPN ;Yes - leave flag on.
LDX #0 ;No - turn off append flag.
STX APPNDFLG
RTNCKAPN RTS
(BA75)
(A6BE) LDX #0 ;Zero out the one-data byte parameter in FM parm list.
STX ONEIOBUF ;(Also referred to as low byte of CURIOBUF.)
FMDRVRTN RTS
(A6C3)
* Prepare to read in file.
(A49D) LDA LENADRBF+1 ;Get hi byte of length just read from disk.
(A4A0) STA LEN2RDWR+1 ;Put length val just read into buffer so know how
;much to read when read in main body of file.
(A4A3) TAY ;Save hi byte in (y).
LDA LENADRBF ;Do likewise with low byte.
STA LEN2RDWR
(A4AA) RTS
- Check to see if there is encough room
- between the program start position and
- MEMSIZ to accomodate file.
(A430) CLC ;Add length of file to start of
(A431) ADC TXTTAB ;program position (normally $801,
;but FP prgm can be loaded at a
;non-standard pos'n by first
;zapping TXTTAB accordingly).
(A433) TAX ;Save low byte of prgm end in (x).
TYA ;Retrieve hi byte of length from (y).
ADC TXTTAB+1
CMP MEMSIZ+1
(A439) BCS TOTOOLRG ;Branch if not enough room.
;(Go issue program-too-large error message.)
- Program is short enough to be
- accomodated in free memory space.
-
- Set zero-page pointers.
(A43B) STA PRGEND+1 ;Set end of program pointer.
STA VARTAB+1 ;Set start of variable space.
STX PRGEND ;PRGEND: val in TXTTAB + length.
STX VARTAB ;VARTAB: val in TXTTAB + length.
LDX TXTTAB
LDY TXTTAB+1
(A447) JSR LODINTFP ;Designate where in free memory to
;load program and then go load it.
* GO DO THE ACTUAL LOAD.
* (Code common to both FP
* and Integer load commands.)
(A471)
LODINTFP STX CURIOBUF ;Designate load addr as I/O buffer
STY CURIOBUF+1 ;in the FM parameter list.
(A477) JMP CLOSEFM ;Use file manager to load the program
------------ ;and then close the file.
* Load the program & then close the file.
(A40A)
CLOSEFM JSR FMDRIVER ;Use file manager to load main body of file.
* USE THE FILE MANAGER DRIVER
* TO READ IN THE FILE.
(A6A8)
FMDRIVER JSR FILEMGR ;Call the file manager to do the function.
* File manager proper.
(AB06)
FILEMGR TSX ;Save the stack pointer so can later
STX STKSAV ;return to the caller of the FM.
(AB0A) JSR RSTRFMWA
* Copy FM work buf (in DOS chain) to
* FM work area (not in DOS chain).
(AE6A)
RSTRFMWA JSR SELWKBUF ;Find FM work buf.
* Get addr of FM
* work buff from
* the FM parm list
* & put it in the
* A4L/H pointer.
(AF08)
SELWKBUF LDX #0
(AF0A) BEQ PT2FMBUF
(AF12)
PT2FMBUF LDA WRKBUFFM,X
STA A4L
LDA WRKBUFFM+1,X
STA A4L+1
(AF1C) RTS
(AE6D) LDY #0 ;Zero out return
(AE6F) STY RTNCODFM ;code in FM parm
;list to assume
;no errors as
(AE72) ;default condition.
STORFMWK LDA (A4L),Y ;Copy FM work buf
STA FMWKAREA,Y ;to FM work area.
INY
CPY #45 ;45 bytes to copy
BNE STORFMWK ;(0 to 44).
CLC ;WHY?????
(AE7D) RTS
(AB0D) LDA OPCODEFM ;Check if opcode is legal.
CMP #13 ;(Must be less than 13.)
BCS TOERROP ;Opcode too large so got range error.
ASL ;Double val of opcode & put it in (x)
TAX ;so it indexes tables of adrs.
LDA FMFUNCTB+1,X ;Stick adr of appropriate function
PHA ;handler on stack (hi byte first).
LDA FMFUNCTB,X
PHA
(AB1E) RTS ;DO STACK JUMP TO FUNCTION ENTRY POINT.
.
.
(AC58)
FNREAD .
.
(See dis'mbly of READ function
and read-a-range (READRNG, $AC96)
subfunction.)
.
.
- reads file into free memory starting
at address designated in TXTTAB (normally $801).
- On entry: LEN2RDWR: contents of LENADRBF (val read off disk).
FILPTSEC: 0, RELPREV:0, FILPTBYT:2,
RECNMBWA: 2, RECNMBFM: 1, BYTOFFWA: 0,
BYTOFFFM: 0 and CURIOBUF = TXTTAB
= free memory target
addr (normally $801).
.
.
(RTS)
============
TOERROP JMP RNGERROP ;Go handle range error.
(AB1F) ------------ ;(See dis'mbly of errors.)
* Return here after doing the READ FUNCTION.
* (Cause after @ function is done, use stack
* to get back to the original caller.)
* Note that (c) = 0 if a byte from a data sector was
* just read -- even if that byte was a $00.
(A6AB)
AFTRFUNC BCC FMDRVRTN ;(c) = 0 = no errors.
LDA RTNCODFM ;Get error code from FM parameter list.
CMP #5 ;End-of-data error?
(A6B2) BEQ TOAPPTCH ;Yes - got a zeroed-out T/S link or a
;zeroed-out data pair listed in a T/S list.
(A6B4) JMP OTHRERR ;No. See dis'mbly of errors.
TOAPPTCH JMP APNDPTCH ;(See dis'mbly of errors.)
NOP
BK2FMDRV JSR CKIFAPND ;Note: APNDPTCH returns here.
(A6BB)
* Check if using the append command.
(BA69)
CKIFAPND LDX CMDINDEX ;Get command index.
CPX #$1C ;Are we APPENDing?
BEQ RTNCKAPN ;Yes - leave flag on.
LDX #0 ;No - turn off append flag.
STX APPNDFLG
RTNCKAPN RTS
(BA75)
(A6BE) LDX #0 ;Zero out the one-data byte parameter in FM parm list.
STX ONEIOBUF ;(Also referred to as low byte of CURIOBUF.)
FMDRVRTN RTS
(A6C3)
(A40D) JMP CMDCLOSE ;Go close the file.
------------
(A2EA)
CMDCLOSE .
.
(See dis'mly of CLOSE command.)
.
.
(RTS)
(A44A) JSR INITIOHK ;Point the I/O hooks at DOS.
* Initialize the I/O hooks so that DOS
* intercepts all input and output. For
* instance, if a routine encounters a
* "COUT JMP (CSW)" then execution will
* actually flow to DOS's output handler
* routine (OPUTINCP, $9EBD). Similarly,
* any routine that refers to "RDKEY JMP (KSW)"
* will actually jump to DOS's input routine
* (INPTINCP, $9E81).
* The true (ie. normal) hooks are saved, ex:
* KSW: KEYIN --> KSWTRUE: KEYIN.
* CSW: COUT1 --> CSWTRUE: COUT1.
* The intercepts are then set as follows:
* ADINCPTCP: INPTINCP --> KSW: INPTINCP.
* ADOPUTCP: OPUTINCP --> CSW: OPUTINCP.
* Check if input hook needs to be reset.
(A851)
INITIOHK LDA KSW+1
CMP ADINPTCP+1
(A856) BEQ CKOUTHK ;Input hook already points to DOS's
;input handler so go check output hook.
* Reset input hook to point to DOS.
(A858) STA KSWTRUE+1 ;KSW: KEYIN --> KSWTRUE: KEYIN.
LDA KSW
STA KSWTRUE
LDA ADINPTCP ;ADINPTCP: INPTINCP --> KSW: INPTINCP.
STA KSW
LDA ADINPTCP+1
(A868) STA KSW+1
* Check if output hook needs to be reset.
(A86A)
CKOUTHK LDA CSW+1
CMP ADOPUTCP+1
(A86F) BEQ SETHKRTN ;Output hook already points to DOS's
;output handler routine, so exit.
* Reset output hook to point to DOS.
(A871) STA CSWTRUE+1 ;CSW: COUT1 --> CSWTRUE: COUT1.
LDA CSW
STA CSWTRUE
LDA ADOPUTCP ;ADOPUTCP: OPUTINCP --> CSW: OPUTINCP.
STA CSW
LDA ADOPUTCP+1
STA CSW+1
SETHKRTN RTS
(A883)
(A44D) JMP (RLOCNTRY) ;Equivalent to "JMP SETLINKS".
;**************** NOTE ********************
;* This is a hacker's dream. If you want *
;* to get fancy & do intelligent tasks *
;* (like preserving variables for the *
;* prgm being loaded), you can zap *
;* RLOCNTRY ($9D60) to point to your own *
;* customized load-handling routines. *
;******************************************
- CAUTION: ENTERING APPLESOFT ROM.
-
- Set important zero-page pointers and
- clear out any variables.
- Adjust stack while retaining the
- return address.
- Fix links (ptrs to next line) in
- each line of Applesoft program.
- Clear all variables & establish forward
- links. (Note: "0 <rtn>" is equivalent
- to "JSR SETLINKS").
(D4F2)
SETLINKS JSR SETZPTRS
(D665)
SETZPTRS JSR SETXTPT
* Set TXTPTR to approximate beginning of
* program (ie. TXTPTR: TXTTAB-1, normally $800).
(D697)
SETXTPT CLC
LDA TXTTAB ;Add negative 1 to low byte.
ADC #$FF
STA TXTPTR
LDA TXTTAB+1 ;Add zero to hi byte if carry set.
ADC #$FF ;Else add neg 1 to hi byte if carry clr.
STA TXTPTR+1
(D6A4) RTS
* Simulate a "CLEAR" statement.
* (Reset variable & string pointers.)
(D668) LDA #0
CLEAR BNE CLRTS
CLEARC LDA MEMSIZ
LDY MEMSIZ+1
STA FRETOP ;FRETOP: MEMSIZ
STY FRETOP+1
LDA VARTAB ;ARYTAB: VARTAB
LDY VARTAB+1
STA ARYTAB
STY ARYTAB+1
STA STREND ;STREND: VARTAB
STY STREND+1
(D680) JSR RESTORE
* Simulate a RESTORE statement. That is, reset
* the pointer which points to bytes in DATA
* statement (DATPTR: TXTTAB-1).
(D849)
RESTORE SEC
LDA TXTTAB
SBC #1
LDY TXTTAB+1
BCS SETDA
DEY
SETDA STA DATPTR ;Otherwise, points to addr
STY DATPTR+1 ;of current DATA statement.
(D857) RTS
* Re-initialize stk while preserving return addr.
(D683)
STKINI LDX #<TEMPST ;Set pointer to descriptor
STX TEMPPT ;for garbage collection.
PLA ;Save return address.
TAY
PLA
LDX #$F8 ;Adjust stack pointer to $1F8 in order to
(D68C) TXS ;leave enough room for links & line # bytes.
;(Actually reserves more space than needed.
;$1FB would have done just fine.)
(D68D) PHA ;Retrieve return address & put it back on stack.
TYA
PHA
LDA #0 ;Defeat any "CONT" statement.
STA OLDTEXT+1 ;Otherwise pts to last byte (an $00) of
STA SUBFLG ;line just executed.
CLRTS RTS
(D696)
- Restablish the link pointer in case
- program wasn't loaded into the same
- position at which it was originally
- written. (THIS ROUTINE ENABLES
- APPLESOFT PROGRAMS TO BE RELOCATABLE.)
- Point index at start of program.
(D4F5)
ESTPTRS LDA TXTTAB
LDY TXTTAB+1
STA INDEX ;INDEX: TXTTAB
(D4FC) STY INDEX+1
- Check if at end of program.
- (ie. Is hi byte of links a "$00"?)
- Remember that the structure of an
- Applesoft program is as follows:
- lnk low / lnk hi / ln # low / ln # hi / token .....etc. / 00 (EOL marker)
(D4FD) CLC
LOCEOP LDY #1
LDA (INDEX),Y ;Get hi byte of present link to next line.
(D502) BNE STARTNXT ;Link not zero, so go find start of next line.
- Found end of program cause link zeroed out.
(D504) LDA VARTAB
STA PRGEND ;Set PRGEND: VARTAB
LDA VARTAB+1
STA PRGEND+1
(D50C) JMP RESTART ;Jump into Basic's warmstart routine.
------------
- Find end of present Applesoft line.
(D50F)
STARTNXT LDY #4
LOCEOL INY ;First possible EOL is offset at (y) = 5.
LDA (INDEX),Y
(D514) BNE LOCEOL
- Calculate address of next line and
- set link in current line to point
- to the start of the next line.
(D516) INY ;Point (y) at start of next line.
TYA
ADC INDEX
TAX ;Save address of start of next line in (x).
LDY #0 ;(y) = 0 for link in current line.
(D51D) STA (INDEX),Y ;Set low byte of link in current line to
;point to start of next line.
(D51F) LDA INDEX+1 ;Calculate hi byte of link.
ADC #0 ;Add 0 if carry clr or add 1 if carry set.
INY
(D524) STA (INDEX),Y ;Set hi byte of link in current line to
;point to start of next line.
(D526) STX INDEX ;Reset index to start of next line.
STA INDEX+1
(D52A) BCC LOCEOP ;ALWAYS.
- ***************************** NOTE *****************************
- *
- Execution now flows into Applesoft's RESTART routine. *
- However, the pattern of program flow depends upon the nature *
- of the caller of the LOAD command. If the LOAD command was *
- called via the RUN command, then execution follows the pattern*
- shown below. If the LOAD command was not called from a RUN, *
- the program exits via the version of the RESTART routine *
- disassembled in the section titled "DOSWARMSTART". *
- *
- ****************************************************************
(D43C)
RESTART JSR CRDO
(DAFB)
CRDO LDA #$0D ;Positive ASCII carriage return.
(DAFD) JSR OUTDO
(DB5C)
OUTDO ORA #$80 ;Convert char to negative ASCII.
CMP #" " ;Is it a ctrl char?
BCC GODOPUT ;Branch if not ctrl char.
ORA FLSHMSK ;Contains #$40 for flash or else is #$00.
GODOPUT JSR COUT
(DB64)
(FDED)
COUT JMP (CSW) ;DOS intercepts output.
------------
(9EBD)
OPUTINCP JSR PREP4DOS
* Save registers & restore hooks.
(9ED1)
PREP4DOS STA ASAVED ;Save (a), (x) & (y)
STX XSAVED ;registers.
STY YSAVED
TSX ;Adjust stk pointer
INX ;& save it so when
INX ;we later restore
(9EDD) STX STKSAVED ;it & hit an "RTS"
;we can return to
;the routine that
;called the routine
;that contained the
;"JSR PREP4DOS"
;instruction.
;(In this case, set
(9EE0) ;to rtn to $DB67.)
UNCONDOS LDX #3
SETRUHKS LDA CSWTRUE,X ;Restore I/O hooks
STA CSW,X ;to point to true
DEX ;I/O handlers.
BPL SETRUHKS ;4 bytes to move
(9EEA) RTS ;(0 TO 3).
* Use current value of OPUTCOND to index
* table containing addresses of output
* condition handlers. Do a "stack jump"
* to appropriate handler.
(9EC0) LDA OPUTCOND
ASL ;Times 2 cause 2 bytes / address.
TAX ;Set (x) to index table of addresses.
LDA OUTHNDTB+1,X ;Put adr of output handler on stack
PHA ;(hi byte first) & then do "stack jump"
LDA OUTHNDTB,X ;to appropriate handler.
PHA
LDA ASAVED ;GET CHAR TO BE PRINTED.
(9ED0) RTS
.
.
STACK JUMP
.
.
OUTPUT HANDLER 0.
(Evaluate start of line.)
(9EEB)
OPUTHDL0 LDX RUNTRUPT ;Contains a nonzero value if RUN cmd was
;interrupted to do a LOAD.
(9EEE) BEQ NONTRUPT ;Branch if RUN not interrupted.
(9EF0) JMP FINSHRUN ;Finish off the RUN command.
------------
(9F78)
FINSHRUN LDA #0 ;ZERO OUT THE RUN INTERCEPT FLAG CUASE
(9F7A) STA RUNTRUPT ;NOW WE'RE INTO THE ROUTINE TO FINISH
;OFF THE RUN COMMAND.
(9F7D) JSR INITIOHK
* Reset the I/O hooks to point to DOS.
(A851)
INITIOHK .
.
(See dis'mbly above.)
.
.
(RTS)
(9F80) JMP RUNFPINT ;JUMP BACK INTO THE RUN COMMAND
------------ ;TO FINISH IT OFF.
;*************** NOTE ******************
;* THE STACK WAS RESET SO WE RETURN TO *
;* THE CORRECT LEVEL. *
;***************************************
===============================
ERROR INTERCEPTION
===============================
- Go issue a type-mismatch error message.
(A410)
TOTYPMIS JMP TYPMISM ;(See dis'mbly of errors.)
------------
- Close file & issue a program-too-large
- error message.
(A4AB)
TOTOOLRG JSR CMDCLOSE
(A2EA)
CMDCLOSE .
.
(See dis'mbly of CLOSE command.)
.
.
(RTS)
(A4AE) JMP TOOLARGE ;(See dis'mbly of errors.)
------------