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-=-=-=-=-=-=-
- ::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::*
- *
- LOCK AND UNLOCK *
- Function Handlers *
- *
- ----------------------------------------------------------------*
- *
- The LOCK and UNLOCK function handlers ($ACEF & $ACF6) *
- set the lock/unlock mask (LOKUNMSK, $B39E) with $80 (lock) *
- or $00 (unlock) and the call the COMNOPEN routine ($AB28) *
- to locate the desired file. COMNOPEN configures the FM work *
- area and then searches the directory sectors for a file *
- description containing the name of the wanted file. (The *
- links to the first directory sector are housed in the VTOC. *
- Each subsequent directory contains the links to the next *
- directory sector. The link bytes of the last directory sector *
- are zeroed out.) *
- Each directory contains up to seven different file *
- descriptions. An example of the information contained in a *
- file description is shown below: *
- FIL1TSTK DS 1 ;Track # of first T/S list for file 1. *
- FIL1TSSC DS 1 ;Sector # of first T/S list for file 1. *
- FIL1TYPE DS 1 ;File type code for file 1. ($00=Text, *
- ;$01=Integer, $02=Applesoft, $04=Binary, *
- ;$08=S-type, $10=Relocatable, $20=A-type *
- ;and $40=B-type.) The hi bit is set on *
- ;locked files. For example, $02=unlocked *
- ;Applesoft and $82=locked Applesoft. *
- FIL1NAME DS 30 ;Name of file 1. If a file name less than *
- ;30 bytes is used, trailing spaces are *
- ;added to the name to fill the buffer. *
- FIL1SIZE DS 2 ;Size of file 1 in terms of the number of *
- ;sectors used. *
- (If a file was deleted, the track # of the file's first T/S *
- list was copied to the last byte position of the name field. *
- The original track # byte (FIL1TSTK) was then overwritten with *
- an #$FF.) *
- As each directory sector is read in, an attempt is made *
- to locate a file description which contains the name of the *
- file wanted. If the name can't be located after searching all *
- the directories, a second search is made to locate the first *
- available space in a directory sector where a new file *
- description can be placed (in case the command can create a *
- new file). If no free space is located, a disk-full error *
- message is printed. *
- If an available space is located, NEWDSCRP ($B2C1) copies *
- the name of the wanted file from the primary file name buffer *
- (PRIMFNBF, $AA75) into the new entry space. A check is then *
- made to see if the command can legally create a new file. The *
- identifying command byte (NDX2CMD, $AA5F) is used to index a *
- table of command attributes (CMDATTRB, $A909). Because bit0 *
- of the first attribute bytes of both the LOCK and UNLOCK *
- commands are clear, neither command can create a new file. As *
- a result, the LOCK or UNLOCK commands are exited with a file- *
- not-found error. *
- If a (non-deleted) description entry containing the name *
- of the wanted file is located, execution branches to the *
- FILLINWA routine ($ABA6). FILLINWA uses the information *
- contained in the description entry to customize the FM work *
- area. Eventhough it is not needed for either the LOCK or *
- UNLOCK functions, the first T/S list belonging to the wanted *
- file is read in (READTS, $A5FE). *
- Next, the accumulator is loaded with the file type code *
- from the file description. The hi bit of the code is dropped *
- by ANDing the accumulator with #$7F. The result is then *
- merged with the LOKUNMSK to set (lock) or clear (unlock) the *
- hi bit. Finally, the updated file type code is put back into *
- the file description. *
- After WRDIRECT ($B037) is called to write the modified *
- directory sector back to the disk, execution returns to the *
- LOCK or UNLOCK command handler. *
- *
- ::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::*
(ACEF)
FNLOCK LDA #$80 ;Set hi bit in lock/unlock mask.
STA LOKUNMSK
(ACF4) BNE COMNLOCK ;ALWAYS.
Unlock Function Handler.
(ACF6)
FNUNLOCK LDA #0 ;Make sure hi bit is clear in the LOKUNMSK.
(ACF8) STA LOKUNMSK
- Routine common to lock/unlock functions.
(ACFB)
COMNLOCK JSR COMNOPEN ;Locate a file with the same name & open it.
*** NOTE ***
* Not all of the common open routine is
* listed below because not all of it
* applies to the lock/unlock functions.
* Common open routine.
(AB28)
COMNOPEN JSR ZWRKAREA ;Initialize the work area.
* Zero out the FM work area so it can be customized
* in accordance with the calling function.
* (Although some work bytes may not be subsequently
* altered, don't be lulled into thinking that they
* are not important. Zero values are just as relevant
* as non-zero values.)
* (P.S. Don't confuse the FM work area with its image
* (FM work buffer) that is housed in the chain of
* DOS buffers.)
(ABDC)
ZWRKAREA LDA #0
TAX ;Initialize the x-index.
ZEROWRKA STA FMWKAREA,X ;Put a $00 byte in work area.
INX
CPX #45 ;Work area is 45 bytes long.
(ABE5) BNE ZEROWRKA
* Begin customizing the work area.
* Get volume, drive, slot & catalog track
* values from the FM parameter list. Put
* drive, slot*16, catalog track and
* complemented volume number in the work area.
(ABE7) LDA VOLFM ;Volume number.
EOR #$FF ;Calculate 1's complement of volume #.
STA VOLWA
LDA DRVFM ;Drive #.
STA DRVWA
LDA SLOTFM ;Get slot #.
ASL ;Calculate slot * 16.
ASL
ASL
ASL
TAX ;Set (x) = slot * 16.
STX SLOT16WA
LDA #$11 ;Normal catalog trk = #17.
STA TRKWA
(AC05) RTS
(AB2B) LDA #1 ;Describe sector length as 256 bytes
(AB2D) STA SECSIZWA+1 ;(in the FM work area).
* Get record length from the FM parameter
* list & put it in the FM work area.
* (Don't allow a zero length. If zero,
* change it to one.)
(AB30) LDX RECLENFM+1
LDA RECLENFM
BNE STRECLEN ;Non-zero record length is ok.
CPX #0
BNE STRECLEN
INX ;Was zero, make it one instead.
STRECLEN STA RECLENWA ;Put length in FM work area.
STX RECLENWA+1
(AB43) JSR GETFNTRY ;Try to find a directory sector for the file.
* Locate or create a file entry in the
* directory buffer.
* Make two searches if necessary:
* - Search1 - try to locate entry with same name as file wanted.
* - Search2 - couldn't locate entry corresponding to file
* wanted so create a new entry in first available
* space in the directory sector.
(B1C9)
GETFNTRY JSR READVTOC ;Read in the VTOC so we can get the link to
;TRKMAPS & to the first directory sector.
* Read the Volume Table of Contents (VTOC).
(AFF7)
READVTOC LDA #1 ;Read opcode for RWTS.
(AFF9) BNE RDWRVTOC ;ALWAYS.
* Code common to read/write VTOC.
(AFFD)
RDWRVTOC LDY ADRVTOC ;Get address of VTOC from the
STY IBBUFP ;FM constants table & designate it
LDY ADRVTOC+1 ;as the I/O buffer in RWTS's IOB.
STY IBBUFP+1
LDX TRKWA ;Enter RWTS driver with (x)/(y) equal
LDY #0 ;to the trk/sec values of the VTOC.
(B00E) JMP RWTSDRVR ;Call driver to read/write the VTOC.
------------
* Read/Write Track/Sector driver.
(B052)
RWTSDRVR .
.
(See dism'bly of RWTS driver using READ.)
.
.
(RTS)
* Point A4L/H at the primary file name buffer.
(B1CC) LDA FNAMBUFM ;Get address of the name buffer from the
STA A4L ;FM parameter list & put it in the A4L/H
LDA FNAMBUFM+1 ;pointer.
(B1D4) STA A4L+1
* Try to find the directory sector with the
* wanted file name & read it into the directory
* sector buffer. Make two searches if necessary.
* On the first search, try to find a matching name.
* If that doesn't work, do a second search to store
* the description in the first available file
* description field in a directory sector.
(B1D6) LDA #1 ;Initialize the search counter (SCRNSRCH)
SETSRCH STA SCRNSRCH ;in the FM scratch space for two searches.
(B1D8) ;(1 = search1, 0 = search2)
(B1DB) LDA #0 ;Initialize offset of file description from
STA SECNXDIR ;the very first directory sector.
CLC ;(c)=0=signal to read first directory sec.
GETDIRSC INC SECNXDIR ;Kick up offset from first directory.
(B1E4) JSR RDDIRECT ;Go read directory sector into buffer.
* Read a directory sector.
(B011)
RDDIRECT PHP ;Save (c) on stack:
; (c) = 0 = read 1rst directory sector.
; (c) = 1 = read next directory sector.
(B012) JSR PT2DIRBF
* Designate the directory sector buffer
* as I/O buffer in RWTS's IOB.
(B045)
PT2DIRBF LDA ADRDIRBF ;Get addr of direc
STA IBBUFP ;sec buf from the
LDA ADRDIRBF+1 ;FM constants tbl
STA IBBUFP+1 ;& designate it as
(B051) RTS ;as the I/O buffer.
(B015) PLP ;Check if 1rst directory sec or not.
(B016) BCS RDNXTDIR ;Go read next directory sector.
* Read the first directory sector.
* (Carry = 0.)
(B018)
RDFIRDIR LDY FIRDIRSC ;(y)/(x) = trk/sec vals of first directory
LDX FIRDIRTK ;sector (from the VTOC buffer).
(B01E) BNE DODIRRD ;ALWAYS - go read in directory sector.
* Read the next directory sector.
* (Carry = 1.)
(B020)
RDNXTDIR LDX DIRLNKTK ;Get track of next directory sec from the
;link in the current directory sector.
(B023) BNE GETDIRLK ;Link not zeroed out.
SEC ;Link zeroed out - exit with (c) = 1 to
(B026) RTS ;signal there are no more directory secs.
=============
(B027)
GETDIRLK LDY DIRLNKSC ;Get sector of next directory sec from the
;link in the current directory sector.
* Call to read in the directory sector.
(B02A)
DODIRRD STX CURDIRTK ;Save trk/sec vals of directory sec that
(B02D) STY CURDIRSC ;we are about to read so they will be
;the current directory sec values for the
;next time around.
(B030) LDA #1 ;Read opcode for RWTS.
(B032) JSR RWTSDRVR ;Call RWTS driver to do the read.
* Read/Write Track/Sector driver.
(B052)
RWTSDRVR .
.
(See dis'mbly of RWTS driver using READ.)
.
.
(RTS)
(B035) CLC ;Link didn't zero out so signal that there
(B036) RTS ;are more directory secs to read & exit.
============
(B1E7) BCS CHNGSRCH ;Link zeroed out, no more directory secs,
;so go switch searches.
(B1E9) LDX #0
CKDIRTRK STX CURDIRNX ;Offset of file description into the current
(B1EB) ;directory sector.
(B1EF) LDA FIL1TSTK,X ;Get track number of first T/S list
;for a particular file from the file
;description entry in the directory sector.
(B1F1) BEQ CHRSRCHA ;If trk=0, no more files in this direc sec.
(B1F3) BMI CHRSRCHB ;Skip deleted file. (When a file is
;deleted, #$FF is put in byte where trk #
;of first T/S list is usually kept.
* Compare the name found in the file
* description entry portion of the
* directory sector with the file name
* wanted. (On entry, A4L/H points at
* the primary file name buffer.)
(B1F5) LDY #0 ;Initialize index to file name buffer.
INX ;Point (x) at the first char position
INX ;in the name field of description entry.
CMPNAMES INX
LDA (A4L),Y ;Get char of name from primary.
CMP FIL1TSTRK,X ;Compare to char in name in description.
BNE DONTMTCH ;Chars (and therefore names) don't match.
INY
CPY #30 ;Done all chars yet (0 to 29)?
BNE CMPNAMES ;Chars matched, branch if more to check.
LDX CURDIRNX ;All chars matched, so names matched.
CLC ;Return with (x) = index to file
(B20A) RTS ;description in current directory sector
============ ;and with (c) = 0 to signal that the
;correct file description was found.
* Advance index to point at the next
* potential file description entry.
(B20B)
DONTMTCH JSR NXPLUS35 ;Names didn't match, so adjust index
;to point at the next entry.
* Add 35 to the offset to point the index
* at the next file description entry.
* (Check to make sure that we don't index
* right off the end of the directory sec.)
(B230)
NXPLUS35 CLC
LDA CURDIRNX
(B234) ADC #35 ;Add 35 to index. (Each file description
;entry is 35 bytes long.)
(B236) TAX ;Check if there is more space for entries
CPX #245 ;in the current directory sector.
(B239) RTS ;Exit with (c) conditioned:
; (c) = 0 = more space in directory.
; (c) = 1 = ran off end of directory.
(B20E) BCC CKDIRTRK ;More potential file descriptions to check
;in this directory sector.
(B210) BCS GETDIRSC ;Go get next directory sector.
------------
* If we just completed first search,
* go back to do second search.
(B212)
CHRSRCHA LDY SCRNSRCH ;(1 = search1, 0 = search2)
(B215) BNE SETSRCH ;Go switch to second search.
* If first search, skip deleted files.
* If second search, fall through to store
* the description in the first unused
* space in the directory.
(B217)
CHRSRCHB LDY SCRNSRCH ;(1 = search1, 0 = search2)
(B21A) BNE DONTMTCH
* Couldn't locate the named file in the
* directory description entries, so begin
* creating a new description in the first available
* space in a directory (in case command can
* legally create a new file).
(B21C)
NWDESCRP LDY #0 ;Initialize index to primary file name buffer.
INX ;Set index to first char position in the
INX ;name field of the file description entry
SETNWNAM INX ;space in the directory sector.
LDA (A4L),Y ;Copy char from primary file name buffer
STA FIL1TSTK,X ;to the directory description space.
INY
CPY #30 ;30 chars in name (0 to 29).
BNE SETNWNAM ;Branch if more chars to copy.
LDX CURDIRNX ;Return with (x) = index to file
SEC ;description space in current directory
(B22F) RTS ;sector & with (c)=1 to signal new entry
============ ;was just created.
* If first search, switch to second search.
* If second search, link zeroed out because
* there isn't enough room left on the
* disk for a new entry. Therefore,
* exit with a disk-full error message.
(B23A)
CHNGSRCH LDA #0 ;Used to reset the search counter if
;go back to start a second search.
(B23C) LDY SCRNSRCH ;(1 = search1, 0 = search2)
BNE SETSRCH ;Just did 1rst search so go start 2nd search.
(B241) JMP DISKFULL ;Even second search was unsuccesful so go
------------ ;handle a disk-full error.
(AB46) BCC FILLINWA ;Branch if found a directory sector with
;name wanted in the file description entry.
* Named file wasn't found in directory,
* so prepare a new file entry in case
* command can legally create a new file.
(AB48) STX CURDIRNX ;Offset to new description entry in
;case want to create a new file.
* Check to see if command can
* legally create a new file.
(AB4B) LDX NDX2CMD ;(x) = index representing command.
(AB4E) LDA CMDATTRB,X ;Get first byte containing description
;of the given command's attributes.
(AB51) LDX CURDIRNX ;(x) = index for new file description
;entry into the directory sector.
(AB54) LSR ;(c) = bit 0 of 1rst attribute byte.
(AB55) BCS CREATNEW ;If (c) = 1, command can create a new file.
;ALWAYS FALL THRU FOR LOCK/UNLOCK FUNCTIONS (cause (c) = 0).
* Command can't create a new file.
* See which language we are using and
* exit with the appropriate error msg.
(AB57)
NEWILLGL LDA CONDNFLG ;$00=warmstart, $01=reading, $40=A(RAM),
;$80=coldstart & $C0=integer.
(AB5A) CMP #$C0 ;Integer in ROM?
BNE TOFILNOT ;No.
(AB5E) JMP LNGNOTAV ;Yes - handle language-not-available error.
------------
TOFILNOT JMP FILENOT ;Handle file-not-found error.
(AB61) ------------
**************** NOTE *************************
* Although it is not needed for the lock/unlock
* functions, the first T/S list sector is automatically
* read into the T/S list buffer (in chain) if the
* file was found.
* Fill in the FM work area buffer.
* (Routine common to opening a new
* or pre-existing file.)
(ABA6)
FILLINWA LDA FIL1TSTK,X ;T/S list trk val (from directory sec).
STA FIRSTSTK
LDA FIL1TSSC,X ;T/S list sec val (from directory sec).
STA FIRTSSEC
LDA FIL1TYPE,X ;File type (from directory sec).
STA FILTYPFM
STA FILTYPWA
LDA FIL1SIZE,X ;File size (from directory sec).
STA FILENSEC
LDA FIL1SIZE+1,X
STA FILENSEC+1
STX BYTNXDIR ;Index into directory sec to description.
LDA #$FF ;Pretend that the last data sector used had
STX RELPREV ;a relative sector number (in relation to
(ABCF) STA RELPREV+1 ;the entire file) of #$FFFF. NOTE: This
;value is later used to trick the read and
;write subfunctions into ignoring the data
;sector currently in memory.
(ABD2) LDA MXIN1TSL ;Dictate that a T/S list can only describe $7A
(ABD5) STA MXSCURTS ;(#122) data sectors. Note: This value is later
;used by the read and write subfunctions to decide
;whether or not the T/S list currently in memory
;should be used.
* Read first T/S list sector
* to the T/S list buffer.
(ABD8) CLC ;(c) = 0 = signal 1rst T/S list sector.
(ABD9) JMP READTS ;Go read in the T/S list sector.
------------
* Read T/S list sector.
(AF5E)
READTS PHP ;Save (c) denoting if 1rst T/S list or not.
;(c) = 0 = read 1rst T/S list sec.
;(c) = 1 = read next T/S list sec.
(AF5F) JSR CKTSUPDT ;Write T/S list sec buf if updating is
;required. (If T/S list buf has changed
;since last read or write, then write it
;back to the disk so don't overwrite buf
;and lose information when read the new
;T/S list sector.)
* Check if T/S list requires updating.
* (ie. Has T/S list buf changed since
* the last read or write?)
(AF34)
CKTSUPDT LDA UPDATFLG
BMI WRITETS ;If bit 7 set, updating is required.
(AF39) RTS ;BRANCH NOT APPLICABLE TO THE LOCK/UNLOCK FUNCTIONS.
(AF62) JSR SETTSIOB ;Prepare RWTS's IOB for READING a T/S list.
* Prepare RWTS's IOB for reading
* or writing the T/S list sector.
(AF4B)
SETTSIOB LDA TSBUFFM ;Get adr of the T/S list buf from the FM
STA IBBUFP ;parameter list & designate T/S list buf
LDA TSBUFFM+1 ;as the I/O buffer in RWTS's IOB.
STA IBBUFP+1
LDX CURTSTRK ;Set (x)/(y) = trk/sec of current T/S list.
LDY CURTSSEC
(AF5D) RTS
(AF65) JSR SELTSBUF ;Select the T/S list buffer.
* Point A4L/H at the T/S list sector buffer.
(AF0C)
SELTSBUF LDX #2 ;Index for T/S list buf.
(AF0E) BNE PT2FMBUF ;ALWAYS.
(AF12)
PT2FMBUF LDA WRKBUFFM,X ;Get address of the desired buffer from
STA A4L ;the FM parameter list & put it in the
LDA WRKBUFFM+1,X ;A4L/H pointer.
STA A4L+1
(AF1C) RTS
(AF68) PLP ;Get saved (c) back from stack.
(AF69) BCS RDNXTTS ;If (c) = 1, already read first T/S list
;sec, so go read next one.
;ALWAYS FALL THRU WITH LOCK/UNLOCK FUNCTIONS (cause (c)=0).
* Read first T/S list sector.
* (Carry was clear.)
(AF6B)
RDFIRSTS LDX FIRSTSTK ;Set (x)/(y)=trk/sec of first T/S list sec.
LDY FIRTSSEC
(AF71) JMP RDTSLST ;Go read T/S list sector into buffer.
------------
* Subroutine to read/write T/S list sector.
(AFB5)
RDTSLST LDA #1 ;Read opcode for RWTS.
* Code common to read/write T/S list.
(AFB7)
RDWRTS STX CURTSTRK ;New T/S list sector trk/sec values (x)/(y)
STY CURTSSEC ;become current T/S list trk/sec values.
(AFBD) JSR RWTSDRVR ;Call RWTS driver to read/write current T/S
;list.
* Read or write the current T/S list.
(B052)
RWTSDRVR .
.
(See dis'mbly of RWTS driver using READ.)
.
.
(RTS)
* Update the FM work area
* (not in DOS buffer chain).
(AFC0) LDY #5 ;Offset into current T/S list buffer.
LDA (A4L),Y ;Get & save the relative sector number of
(AFC4) STA RELFIRST ;the first data sector described in this
;T/S list.
(AFC7) CLC ;Add the maximum # of data secs that
ADC MXSCURTS ;can be described in this T/S list ($7A, #122).
STA RELASTP1 ;Store relative sector number (plus 1) of
INY ;the last data sector described in list.
LDA (A4L),Y
STA RELFIRST+1
ADC MXSCURTS+1
STA RELASTP1+1 ;(RELASTP1/+1 is always set to $007A by FNOPEN.)
CLC ;Return with "no error" signal.
(AFDB) RTS
============
(ACFE) LDX CURDIRNX ;(x) = index to file description entry
;in the directory sector buffer.
(AD01) LDA FIL1TYPE,X ;Get old file type.
AND #$7F ;Shut hi bit off.
(AD06) ORA LOKUNMSK ;Merge with LOKUNMSK to set (lock) or clear
;(unlock) the hi bit.
(AD09) STA FIL1TYPE,X ;Stick modified file type back into the
;file description part of the directory
;sector buffer.
(AD0C) JSR WRDIRECT ;Write the updated directory sec buf to disk.
* Write the directory buffer.
(B037)
WRDIRECT JSR PT2DIRBF
* Designate the directory sector buffer
* as the I/O buffer in RWTS's IOB.
(B045)
PT2DIRBF LDA ADRDIRBF ;Get the addr of the directory sec buf
STA IBBUFP ;in the FM constants table.
LDA ADRDIRBF+1 ;Store it in RWTS's IOB.
STA IBBUFP+1
(B051) RTS
(B03A) LDX CURDIRTK ;Enter RWTS driver with (x)/(y) = trk/sec vals.
LDY CURDIRSC
LDA #2 ;Write opcode for RWTS.
(B042) JMP RWTSDRVR ;Call RWTS driver to write the directory sector buffer.
------------
(B052)
RWTSDRVR .
.
(See dis'mbly of RWTS driver using WRITE.)
.
.
(RTS)
(AD0F)
TOOKFMXT JMP GOODFMXT ;Exit the file manager cleanly.
------------
- Exit the file manager with or without errors.
(B35F)
LNGNOTAV LDA #1
(B361) BNE BADFMXIT ;ALWAYS.
(B373)
FILENOT LDA #6
(B375) BNE BADFMXIT ;ALWAYS.
(B377)
DISKFULL JMP FULLPTCH ;(See dis'mbly of errors.)
(B37F)
GOODFMXT LDA RTNCODFM
CLC ;(c) = 0 to signal good operation.
BCC FMEXIT
BADFMXIT SEC ;(c) = 1 to signal unsuccessful.
FMEXIT PHP ;Save status on stack.
STA RTNCODFM ;Store return code in FM parameter list.
LDA #0
STA STATUS
(B38E) JSR CPYFMWA ;Copy the work area to the work buffer.
* Copy the FM work area (non-chain) to
* the FM work buffer (in DOS chain).
(AE7E)
CPYFMWA JSR SELWKBUF ;Select the FM work buffer (in DOS chain).
* Point the A4L/H pointer at the FM work buffer.
(AF08)
SELWKBUF LDX #0 ;Set index to select work buffer.
(AF0A) BEQ PT2FMBUF ;ALWAYS.
(AF12)
PT2FMBUF LDA WRKBUFFM,X ;Get address of selected buffer from the
STA A4L ;FM parameter list & put it in the pointer.
LDA WRKBUFFM+1,X
STA A4L+1
(AF1C) RTS
(AE81) LDY #0 ;Initialize index.
STORWRK LDA FMWKAREA,Y ;Get byte from the FM work area.
STA (A4L),Y ;Put it in the work buffer.
INY
CPY #45 ;45 bytes to copy (0 to 44).
BNE STORWRK
(AE8D) RTS
(B391) PLP ;Retrieve status of success of operation
;from the stack.
(B392) LDX STKSAV ;Adjust stack pointer to force exit to the
TXS ;caller of the function handler even if we
(B396) RTS ;are several subroutines deeper than the
============ ;original entry point. (That is, return
;to AFTRFUNC ($A6AB) in the FMDRIVER routine
;($A6A8).)