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BIOS3.AQM
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BIOS3.ASM
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Assembly Source File
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2000-06-30
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38KB
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1,318 lines
*****************************************************************
* *
* BIOS and Loader BIOS for CP/M Plus (Beta V1.2) for DJ2D *
* controller. *
* Written November 1982 by Dave Hardy and Ken Jackson *
* *
*****************************************************************
TITLE 'BIOS and Loader BIOS For CP/M Plus'
*****************************************************************
* *
* To install this BIOS into CP/M Plus, perform the following *
* steps: *
* 1. Add your own console and printer I/O to this file *
* at CONIN:, CONOUT:, CONST:, LIST:, and LISTST: *
* 2. Add any initialization that you need at TINIT: *
* 3. Set the LDRBIOS equate in this file to TRUE *
* 4. RMAC SCB $PZ -S (assemble SCB.ASM, supplied) *
* 5. RMAC BIOS3 $PZ -S (assemble LDRBIOS) *
* 6. REN LDRBIOS.REL=BIOS3.REL *
* 7. Set the LDRBIOS equate in this file FALSE *
* 8. RMAC BIOS3 $PZ -S (assemble BIOS) *
* 9. LINK BIOS3[B]=BIOS3,SCB *
* 10. GENCPM *
* (answer all questions with a carriage return, *
* except answer "N" at "Bank switched memory?" *
* question, and answer with your top page of *
* memory when asked "Top page of memory?") *
* 11. LINK CPMLDR[L100]=CPMLDR,LDRBIOS *
* 12. CPMLDR (Load and run CP/M Plus) *
* *
*****************************************************************
FALSE EQU 0 ;Define TRUE and FALSE
TRUE EQU NOT FALSE
*****************************************************************
* *
* The following revision number is in reference to the CP/M *
* Plus BIOS. *
* *
*****************************************************************
REVNUM EQU 10 ;BIOS revision number
CPMREV EQU 30 ;CP/M revision number
*****************************************************************
* *
* These are the routines called from the DJ2D's built-in EPROM. *
* (model B only) *
* *
*****************************************************************
ORIGIN EQU 0F800H ;EPROM origin of your DJ2D board
DJRAM EQU ORIGIN+400H ;DJ2D RAM address
DJHOME EQU DJRAM+9H ;DJ2D track zero seek
DJTRK EQU DJRAM+0CH ;DJ2D track seek routine
DJSEC EQU DJRAM+0FH ;DJ2D set sector routine
DJDMA EQU DJRAM+012H ;DJ2D set DMA address
DJREAD EQU DJRAM+15H ;DJ2D read routine
DJWRITE EQU DJRAM+18H ;DJ2D write routine
DJSEL EQU DJRAM+1BH ;DJ2D select drive routine
DJSTAT EQU DJRAM+27H ;DJ2D status routine
DJSIDE EQU DJRAM+30H ;DJ2D set side routine
*****************************************************************
* *
* Miscellaneous internal BIOS equates. *
* We've tried to maintain compatibility with the Morrow's DJ2D *
* BIOS. *
* *
*****************************************************************
LDRBIOS EQU FALSE ;TRUE, if want to assemble as Loader BIOS
UD2 EQU TRUE ;TRUE, if want to use User/Drive byte @ addr 4
CDISK EQU 4 ;Address of last logged disk
BUFF EQU 80H ;Default buffer address
TPA EQU 100H ;Transient memory
ENTRY EQU 5 ;BDOS entry jump address
RETRIES EQU 10 ;Max retries on disk i/o before error
ACR EQU 0DH ;A carriage return
ALF EQU 0AH ;A line feed
MAXDISK EQU 4 ;Maximum # of disk drives
CLEAR EQU 1AH ;Clear Screen code for LDRBIOS
*****************************************************************
* *
* PUBLIC and EXTERNAL declarations required for CP/M Plus. *
* *
*****************************************************************
CSEG
PUBLIC ?BOOT,?WBOOT,?CONST,?CONIN,?CONO,?LIST,?AUXO,?AUXI
PUBLIC ?HOME,?SLDSK,?STTRK,?STSEC,?STDMA,?READ,?WRITE
PUBLIC ?LISTS,?SCTRN
PUBLIC ?CONOS,?AUXIS,?AUXOS,?DVTAB,?DEVIN,?DRTBL,?MLTIO,?FLUSH
PUBLIC ?MOV,?TIM,?BNKSL,?STBNK,?XMOV
IF NOT LDRBIOS
PUBLIC ?INIT,?LDCCP
EXTRN @CIVEC,@COVEC,@AIVEC,@AOVEC,@LOVEC,@MXTPA
ENDIF
*****************************************************************
* *
* THE BIOS JUMP TABLE *
* *
* The jump table below must remain in the same order, the *
* routines may be changed, but the function executed must be *
* the same. There are 33 jumps in the CP/M Plus BIOS vector. *
* *
*****************************************************************
;
?BOOT: JMP CBOOT ; cold start entry point
WBOOTE:
?WBOOT: JMP WBOOT ; warm start entry point
?CONST: JMP CONST ; console status A=ff=ready
?CONIN: JMP CONIN ; console input data in A
COUT:
?CONO: JMP CONOUT ; console output data in C
?LIST: JMP LIST ; list device data in C
?AUXO: JMP AUXOUT ; punch device none
?AUXI: JMP AUXIN ; reader device none
?HOME JMP HOME ; seek home track
?SLDSK: JMP SETDRV ; select disk disk in C
?STTRK: JMP SETTRK ; seek track track in BC
?STSEC: JMP SETSEC ; set sector sector in BC
?STDMA: JMP SETDMA ; set dma dma in BC
?READ: JMP READ ; read sector
?WRITE: JMP WRITE ; write sector
?LISTS: JMP LISTST ; return list status A=FF=ready
?SCTRN: JMP SECTRAN ; sector translate sector in BC
?CONOS: JMP CONOST ; Return Output Status of Console
?AUXIS: JMP AUXIST ; Return Input Status of Aux. Port
?AUXOS: JMP AUXOST ; Return Output Status of Aux. Port
?DVTAB: JMP DEVTBL ; Return Address of Char. I/O Table
?DEVIN: JMP DEVINI ; Initialize Char. I/O Devices
?DRTBL: JMP DRVTBL ; Return Address of Disk Drive Table
?MLTIO: JMP MULTIO ; Set number of logically conseqcuitive
; sectors to be read or written
?FLUSH: JMP FLUSH ; Force Physical Buffer Flushing for
; user-supported deblocking
?MOV: JMP MOVE ; Memory Move for Large Memory Copy
?TIM: JMP ?TIME ; Get The Time
?BNKSL: JMP SELMEM ; Select Alternate Bank of Memory
?STBNK: JMP SETBNK ; Select Bank for DMA Operation
?XMOV: JMP XMOVE ; Set Bank When a Buffer is in a Bank
; other than 0 or 1
DJDRV JMP DJSEL ; Hook for SINGLE.COM program
; Reserved for System Implementor
JMP RESERV1 ; Reserved for CP/M Plus
JMP RESERV2 ; Reserved for CP/M Plus
;
; Device Table is not implemented, so return HL=0
DEVTBL: LXI H,0
RET
;
; Flush routine is not implemented, so return A=0
FLUSH: XRA A
RET
;
; Drive Table is not used, so return HL=0FFFEH
DRVTBL: LXI H,0FFFEH
RET
;
; The following jumps from the BIOS jump vector are not implemented:
CONOST:
AUXIST:
AUXOUT:
AUXIN:
AUXOST:
DEVINI:
MULTIO:
XMOVE:
SELMEM:
SETBNK:
RESERV1:
RESERV2:
?TIME:
RET
*****************************************************************
* *
* Cold-boot sign-on message *
* *
*****************************************************************
PROMPT:
IF LDRBIOS
DB ACR,ALF,ALF
DB 'Loader for Morrow Designs DJ2D Controller.'
DB ACR,ALF,0
ENDIF
;
IF NOT LDRBIOS
DB ACR,ALF,ALF
DB 'CP/M Plus (V' ;CP/M version number
DB CPMREV/10+'0'
DB '.'
DB (CPMREV MOD 10)+'0'
DB '), BIOS rev '
DB REVNUM/10+'0','.' ;Cbios revision number
DB REVNUM MOD 10+'0'
DB ACR,ALF
DB 'For Morrow Designs DJ2D Controller '
DB '@ 0'
IF ORIGIN/4096 > 10 ;Controller origin (HEX)
DB ORIGIN/4096+'A'-10
ELSE
DB ORIGIN/4096+'0'
ENDIF
IF (ORIGIN/256 AND 0FH) > 10
DB (ORIGIN/256 AND 0FH)+'A'-10
ELSE
DB (ORIGIN/256 AND 0FH)+'0'
ENDIF
DB '00H.'
DB ACR,ALF,0
ENDIF
*****************************************************************
* *
* Utility subroutine to output the message pointed at by H&L, *
* terminated with a null. Used only during cold boot. *
* *
*****************************************************************
MESSAGE MOV A,M ;Get a character of the message
INX H ;Bump text pointer
ANA A ;Test for end
RZ ;Return if done
PUSH H ;Save pointer to text
MOV C,A ;Output character in C
CALL COUT ;Output the character
POP H ;Restore the pointer
JMP MESSAGE ;Continue until null reached
*****************************************************************
* *
* System initialization Subroutine *
* Put any initialization procedures required by your system *
* here (e.g. setting up UARTS, etc.) *
* *
*****************************************************************
IF LDRBIOS ;Then perform any initializations
TINIT: MVI C,CLEAR ; that your system requires
CALL COUT ;Clear the console screen
RET
ENDIF
*****************************************************************
* *
* Cold boot routines *
* *
*****************************************************************
CBOOT:
IF LDRBIOS ;Then Initialize terminal or whatever
CALL TINIT
ENDIF
;
IF NOT LDRBIOS
LXI SP,TPA ;Set up stack
ENDIF
;
LXI H,PROMPT ;Prep for sending signon message
CALL MESSAGE ;Send the prompt
XRA A ;Select disk A
STA CPMDRV
STA CDISK
;
IF NOT LDRBIOS
CALL ?INIT ;Initialize page zero and SCB
JMP WBOOT ;Warm-boot
;
; System initialization subroutine
?INIT: MVI A,JMP ;Set up jumps at addresses 0 and 5
STA 0
STA 5
LXI H,WBOOTE
SHLD 1
LHLD @MXTPA
SHLD 6
LXI H,1 ;Initialize System Control Block
SHLD @CIVEC
SHLD @COVEC
LXI H,2
SHLD @LOVEC
LXI H,4
SHLD @AIVEC
SHLD @AOVEC
LXI H,LOG$MSG ;Print sign-on message on console
CALL MESSAGE
RET
*****************************************************************
* *
* Subroutine to load the CCP into memory at address 100H *
* *
*****************************************************************
?LDCCP: XRA A
STA CCP$FCB+15 ;Start with extent 0
LXI H,0
SHLD FCB$NR ;Record 0
LXI D,CCP$FCB
CALL OPEN ;Open file CCP.COM
INR A
JZ NO$CCP ;Tell if no file found
LXI D,0100H ;Else
CALL SETBUF ;Set to load into TPA
LXI D,128
CALL SETMULTI ;Allow up to 16k bytes
LXI D,CCP$FCB
CALL REBOOT ;Read file into memory
RET
;
; Print error message if can't find CCP.COM on default drive
NO$CCP: LXI H,CCP$MSG
CALL MESSAGE ;REPORT THIS
CALL ?CONIN ;GET A RESPONSE
JMP ?LDCCP ;AND TRY AGAIN
;
; CP/M BDOS function interface used to load CCP.COM
OPEN: MVI C,15
JMP BDOSGO ;OPEN FILE CONTROL
SETMULTI:
MVI C,44
JMP BDOSGO ;SET MULTI RECORD COUNT
REBOOT: MVI C,20
JMP BDOSGO ;READ RECORDS
SETBUF: MVI C,26
JMP BDOSGO ;SETDMA
BDOSGO: LHLD @MXTPA
PCHL
;
; Miscellaneous messages for console
LOG$MSG:
DB 13,10,13,10,'CP/M Version 3.0',00
CCP$MSG:
DB 13,10,'BIOS Err on A: NO CCP.COM file',00
;
; File Control Block used to load CCP.COM
CCP$FCB:
DB 1,'CCP ','COM',0,0,0,0
DS 16
FCB$NR: DB 0,0,0
ENDIF ;NOT LDRBIOS
*****************************************************************
* *
* Warm-boot subroutine *
* *
*****************************************************************
WBOOT:
IF NOT LDRBIOS
LXI SP,TPA ;Set up stack pointer
ENDIF
;
LXI D,BUFF ;Set up initial DMA address
CALL SETDMA
;
IF NOT LDRBIOS
CALL ?LDCCP ;Load the CCP.COM file into the TPA
ENDIF
;
MVI A,JMP ;Set up jumps at addresses 0 and 5
STA 0
STA 5
LXI H,WBOOTE
SHLD 1
;
IF NOT LDRBIOS
LHLD @MXTPA
SHLD 6
;
IF UD2
; This conditional is used if you want the system to read the
; USER/DRIVE byte at address 4 during each warm-boot, to maintain
; compatibility with certain CP/M 2.2 programs that modify this byte
; to change default user area of drive. Making this conditional TRUE
; may cause some unusual side-effects when you warm-boot while logged
; into any drive other than 'A' drive. Note also that the location of
; the warm-boot user and drive bytes in the SCB is undocumented, so it
; may be changed from the address assumed here. This may also have been
; changed since the Beta 1.2 version that we evaluated, so use it with
; a great deal of caution.
;
; Copy USER/DRIVE byte from address 4 into the System Control Block
LHLD 1 ;Get address page of BIOS
DCR H ;Point to default drive byte in SCB
MVI L,0AFH
LDA 4 ;Get default drive from User/Drive byte
ANI 0FH
MOV M,A ;Store DRIVE in SCB
INX H ;Point to default user byte in SCB
LDA 4 ;Get default user from User/Drive byte
RRC
RRC
RRC
RRC
ANI 0FH
MOV M,A ;Store USER in SCB
;
ENDIF ;UD2
ENDIF ;NOT LDRBIOS
;
LDA CDISK ;Put current disk into A
MOV C,A
;
IF NOT LDRBIOS
JMP 0100H ;Jump to CCP
ENDIF
;
IF LDRBIOS
RET ;Return to loader
ENDIF
*****************************************************************
* *
* General purpose memory move subroutine. *
* Moves BC bytes from DE to HL *
* *
*****************************************************************
MOVE: LDAX D
MOV M,A
INX D
INX H
DCR C
JNZ MOVE
MOV A,B
ORA C
RZ
DCR B
JMP MOVE
*****************************************************************
* *
* Setsec subroutine saves the desired sector to seek to until *
* an actual read or write is attempted. *
* *
*****************************************************************
SETSEC MOV A,C ;Save the sector number
STA CPMSEC
RET
*****************************************************************
* *
* Setdma subroutine saves the DMA address for the data transfer.*
* *
*****************************************************************
SETDMA MOV H,B ;Save DMA address that is in BC
MOV L,C
SHLD CPMDMA
RET
*****************************************************************
* *
* Home subroutine does a seek to track zero. *
* *
*****************************************************************
HOME MVI C,0 ;Track to seek to
*****************************************************************
* *
* Settrk subroutine saves the TRK # to seek to. Nothing is done *
* until an actual read or write. *
* *
*****************************************************************
SETTRK MOV A,C
STA CPMTRK
RET
*****************************************************************
* *
* Sectran subroutine translates a logical sector # into a *
* physical sector #. Note that this routine is similar to the *
* original one used in the DJ2D CP/M 2 BIOS, but has some *
* significant differences. *
* *
*****************************************************************
SECTRAN INX B
PUSH D ;Save table address
PUSH B ;Save sector #
CALL GETDPB ;Get DPB address into HL
MOV A,M ;Get # of CP/M sectors/track
ORA A ;Clear carry
RAR ;Divide by two
SUB C
PUSH PSW ;Save adjusted sector
JM SIDETWO
SIDEA POP PSW ;Discard adjusted sector
POP B ;Restore sector requested
POP D ;Restor address of xlt table
SIDEONE XCHG ;exchange DPB and table address
DAD B ;bc = offset into table
MOV L,M ;hl <- physical sector
MVI H,0
RET
SIDETWO LXI B,17 ;Offset to side bit
DAD B
MOV A,M
ANI 8 ;Test for double sided
JZ SIDEA ;Media is only single sided
POP PSW ;Retrieve adjusted sector
POP B
CMA ;Make sector request positive
INR A
MOV C,A ;Make new sector the requested sector
POP D
CALL SIDEONE
MVI A,80H ;Side two bit
ORA L ; and sector
MOV L,A
RET
*****************************************************************
* *
* Setdrv subroutine selects the next drive to be used in *
* read/write operations. If the drive has never been selected *
* before, a parameter table is created which correctly *
* describes the diskette currently in the drive. Diskettes can *
* be of four different sector sizes: *
* 1) 128 bytes single density. *
* 2) 256 bytes double density. *
* 3) 512 bytes double density. *
* 4) 1024 bytes double density. *
* Note the changes made for CP/M 3.0 *
* *
*****************************************************************
SETDRV MOV A,C ;Save the drive #
STA CPMDRV
CPI MAXDISK ;Check for a valid drive #
JNC ZRET ;Illegal drive #
MOV A,E ;Test if drive ever logged in before
ANI 1
JNZ SETDRV1 ;Bit 0 of E = 0 means never selected before
MVI A,1 ;Select sector 1 of track 1
STA TRUESEC
STA CPMTRK
CALL FILL ;Flush buffer and refill
JC ZRET ;Test for error return
CALL DJSTAT ;Get status on current drive
ANI 2CH ;Look at side and denstiy bits
MOV E,A
ANI 20H
MOV A,E
JNZ SETDR1
ORI 10H
SETDR1: RAR
PUSH PSW ;Save DJSTAT single/double-sided info
ANI 6
LXI H,XLTS ;Table of XLT addresses
PUSH H
MOV E,A
MVI D,0
DAD D
PUSH H ;Save pointer to proper XLT
CALL GETDPB ;Get DPH pointer into DE
XCHG ;
POP D
MVI B,2 ;Number of bytes to move
CALL MOVLOP ;Move the address of XLT
LXI D,10 ;Offset to DPB pointer
DAD D ;Point HL to DPB address
XCHG ;Point HL to DBP base, DE to &DPH.DPB
POP H
POP PSW ;Offset to correct DPB
MOV C,A
MVI B,0
DAD B ;Add to translate table to point to density
;(The DPB table is cleverly located right
; after the xlt table)
XCHG ;Put DPB address in DPH
MVI B,2 ;Move DPB address into DPH
CALL MOVLOP
SETDRV1 CALL GETDPB ;Get address of DPB in HL
LXI B,17 ;Offset to sector size
DAD B
MOV A,M ;Get sector size
ANI 7H
STA SECSIZ
MOV A,M
RAR
RAR
RAR
RAR
ANI 0FH
STA SECPSEC ;Single/double-sided flag
XCHG ;HL to DPH
RET
ZRET LXI H,0 ;Seldrv error exit
RET
*****************************************************************
* *
* Getdpb subroutine returns HL pointing to the DPB of the *
* currently selected drive, DE pointing to DPH. *
* *
*****************************************************************
GETDPB: LDA CPMDRV ;Get drive #
LXI H,DPZERO
LXI D,19H
GETDP1: ORA A
JZ GETDP2
DAD D
DCR A
JMP GETDP1
;
GETDP2: PUSH H ;Save address of DPH
LXI D,12 ;Offset to DPB
DAD D
MOV A,M ;Get low byte of DPB address
INX H
MOV H,M ;Get low byte of DPB
MOV L,A
POP D
RET
*****************************************************************
* *
* xlts points to a table of addresses that point to each *
* of the xlt tables for each sector size. *
* *
* The table following the xlt's is a table of the DPB's, used *
* by the SETDRV subroutine to calculate density *
* *
*****************************************************************
XLTS DW XLT128 ;Xlt for 128 byte sectors
DW XLT256 ;Xlt for 256 byte sectors
DW XLT512 ;Xlt for 512 byte sectors
DW XLT124 ;Xlt for 1024 byte sectors
;
DW DPB128S ;DPB FOR 128 BYTE SECTORS SINGLE SIDE
DW DPB256S ;DPB FOR 256 BYTE SECTORS SINGLE SIDE
DW DPB512S ;DPB FOR 512 BYTE SECTORS SINGLE SIDE
DW DP1024S ;DPB FOR 1024 BYTE SECTORS SINGLE SIDE
DW DPB128D ;DPB FOR 128 BYTE SECTORS DOUBLE SIDE
DW DPB256D ;DPB FOR 256 BYTE SECTORS DOUBLE SIDE
DW DPB512D ;DPB FOR 512 BYTE SECTORS DOUBLE SIDE
DW DP1024D ;DPB F0R 1024 BYTE SECTORS DOUBLE SIDE
*****************************************************************
* *
* Write subroutine moves data from memory into the buffer. If *
* the desired CP/M sector is not contained in the disk buffer, *
* the buffer is first flushed to the disk if it has ever been *
* written into, then a read is performed into the buffer to get *
* the desired sector. Once the correct sector is in memory, the *
* buffer written indicator is set, so the buffer will be *
* flushed, then the data is transferred into the buffer. *
* *
*****************************************************************
WRITE MOV A,C ;Save write command type
STA WRITTYP
MVI A,1 ;Set write command
DB (MVI) OR (B*8) ;Fake "mvi b" instruction will
; cause the following "xra a" to
; be skipped over.
;This is the same (ugh) trick that
;Morrow's used, but it works...
*****************************************************************
* *
* Read subroutine to buffer data from the disk. If the sector *
* requested from CP/M is in the buffer, then the data is simply *
* transferred from the buffer to the desired dma address. If *
* the buffer does not contain the desired sector, the buffer is *
* flushed to the disk if it has ever been written into, then *
* filled with the sector from the disk that contains the *
* desired CP/M sector. *
* *
*****************************************************************
READ XRA A ;Set the command type to read
STA RDWR ;Save command type
;
; Redwrt calculates the physical sector on the disk that
; contains the desired CP/M sector, then checks if it is the
; sector currently in the buffer. If no match is made, the
; buffer is flushed if necessary and the correct sector read
; from the disk.
REDWRT MVI B,0 ;The 0 is modified to contain the log2
SECSIZ EQU $-1 ; of the physical sector size/128
; on the currently selected disk.
;(Another Morrow trick)
LDA CPMSEC ;Get the desired CP/M sector #
PUSH PSW ;Temporary save
ANI 80H ;Save only the side bit
MOV C,A ;Remember the side
POP PSW ;Get the sector back
ANI 7FH ;Forget the side bit
DCR A ;Temporary adjustment
DIVLOOP DCR B ;Update repeat count
JZ DIVDONE
ORA A ;Clear the carry flag
RAR ;Divide the CP/M sector # by the size
; of the physical sectors
JMP DIVLOOP ;
DIVDONE INR A
ORA C ;Restore the side bit
STA TRUESEC ;Save the physical sector number
LXI H,CPMDRV ;Pointer to desired drive,track, and sector
LXI D,BUFDRV ;Pointer to buffer drive,track, and sector
MVI B,4 ;Count loop
DTSLOP DCR B ;Test if done with compare
JZ SECMOV ;Yes, match. Go move the data
LDAX D ;Get a byte to compare
CMP M ;Test for match
INX H ;Bump pointers to next data item
INX D
JZ DTSLOP ;Match, continue testing
;
; If drive, track, and sector don't match, then flush the buffer if
; necessary and refill.
CALL FILL ;Get correct physical sector into buffer
RC ;Return error if no good
;
; SECMOV has been previously modified to cause either a transfer
; into or out of the buffer. (Yet another Morrow trick)
SECMOV LDA CPMSEC ;Get the CP/M sector to transfer
DCR A ;Adjust to proper sector in buffer
ANI 0 ;Strip off high ordered bits
SECPSEC EQU $-1 ;The 0 is modified to represent the # of
; CP/M sectors per physical sectors
MOV L,A ;Put into HL
MVI H,0
DAD H ;Form offset into buffer
DAD H
DAD H
DAD H
DAD H
DAD H
DAD H
LXI D,BUFFER ;Beginning address of buffer
DAD D ;Form beginning address of sector to transfer
XCHG ;DE = address in buffer
LXI H,0 ;Get DMA address, the 0 is modified to
; contain the DMA address
CPMDMA EQU $-2
MVI A,0 ;The zero gets modified to contain
; a zero if a read, or a 1 if write
RDWR EQU $-1
ANA A ;Test which kind of operation
JNZ INTO ;Transfer data into the buffer
CALL MOVER
XRA A
RET
INTO XCHG ;
CALL MOVER ;Move the data, HL = destination
; DE = source
MVI A,1
STA BUFWRTN ;Set buffer written into flag
MVI A,0 ;Check for directory write
WRITTYP EQU $-1
DCR A
MVI A,0
STA WRITTYP ;Set no directory write
RNZ ;No error exit
*****************************************************************
* *
* FLUSHA subroutine writes the contents of the buffer out to *
* the disk if it has ever been written into. *
* *
*****************************************************************
FLUSHA MVI A,0 ;The 0 is modified to reflect if
; the buffer has been written into
BUFWRTN EQU $-1
ANA A ;Test if written into
RZ ;Not written, all done
LXI H,DJWRITE ;Write operation
;
; Prep prepares to read/write the disk. Retries are attempted.
; Upon entry, H&L must contain the read or write operation
; address.
PREP XRA A ;Reset buffer written flag
STA BUFWRTN
SHLD RETRYOP ;Set up the read/write operation
MVI B,RETRIES ;Maximum number of retries to attempt
RETRYLP PUSH B ;Save the retry count
LDA BUFDRV ;Get drive number involved in the operation
MOV C,A
CALL DJDRV ;Select the drive
LDA BUFTRK
ANA A ;Test for track zero
MOV C,A
PUSH B
CZ DJHOME ;Home the drive if track 0
POP B ;Restore track #
CALL DJTRK ;Seek to proper track
LDA BUFSEC ;Get sector involved in operation
PUSH PSW ;Save the sector #
RLC ;Bit 0 of A equals side #
ANI 1 ;Strip off unnecessary bits
MOV C,A ;C <- side #
CALL DJSIDE ;Select the side
POP PSW ;A <- sector #
ANI 7FH ;Strip off side bit
MOV C,A ;C <- sector #
CALL DJSEC ;Set the sector to transfer
LXI B,BUFFER ;Set the DMA address
CALL DJDMA
CALL DJREAD ;The read operation is modified to write
RETRYOP EQU $-2
POP B ;Restore the retry counter
MVI A,0 ;No error exit status
RNC ;Return no error
DCR B ;Update the retry counter
STC ;Assume retry count expired
MVI A,0FFH ;Error return
RZ
JMP RETRYLP ;Try again
*****************************************************************
* *
* Fill subroutine fills the buffer with a new sector *
* from the disk. *
* *
*****************************************************************
FILL CALL FLUSHA ;Flush buffer first
RC ;Check for error
LXI D,CPMDRV ;Update the drive, track, and sector
LXI H,BUFDRV
MVI B,3 ;Number of bytes to move
CALL MOVLOP ;Copy the data
LXI H,DJREAD
JMP PREP ;Select drive, track, and sector.
; Then read the buffer
*****************************************************************
* *
* Mover subroutine moves 128 bytes of data. Source pointer *
* in DE, Dest pointer in HL. *
* *
*****************************************************************
MOVER MVI B,128 ;Length of transfer
MOVLOP LDAX D ;Get a bte of source
MOV M,A ;Move it
INX D ;Bump pointers
INX H
DCR B ;Update counter
JNZ MOVLOP ;Continue moving until done
RET
*****************************************************************
* *
* Terminal driver subroutines. Note that the console device *
* is NOT the DJ2D memory-mapped serial I/O port. *
* *
*****************************************************************
*****************************************************************
* *
* const: get the status for the console *
* *
*****************************************************************
CONST IN 80H ;Read console status port
ANI 40H
MVI A,0
RZ ;Return A=0, if no character waiting
INR A
RET ;Else return A=01H
*****************************************************************
* *
* conin: get a character from the console *
* *
*****************************************************************
CONIN: IN 80H ;Read console status port
ANI 40H
JZ CONIN ;Wait for a character
IN 81H ;Read the console data port
ANI 7FH ;Mask the MSB
RET ;Return with the character in A
*****************************************************************
* *
* conout: send a character to the console *
* *
*****************************************************************
CONOUT IN 80H ;Read the console status port
ANI 80H
JZ CONOUT ;Wait until character can be sent
MOV A,C
OUT 81H ;Send character to console data port
RET ;Return
*****************************************************************
* *
* listst: get the status for the list device. Note that the *
* list device used is the memory-mapped DJ2D serial I/O port. *
* *
*****************************************************************
LISTST: LDA ORIGIN+3F9H ;Read printer status port (memory mapped)
CMA ; (invert to positive logic)
ANI 08H
MVI A,00H
RZ ;return A=0, if not ready
MVI A,0FFH ;return A=0FFH, if ready
RET
*****************************************************************
* *
* list: send a character to the list device *
* *
*****************************************************************
LIST: LDA ORIGIN+3F9H ;Read list device status (memory mapped)
CMA ; (invert it to positive logic)
ANI 08H ;Wait until ok to send
JZ LIST
MOV A,C ;Send the character
CMA ; (invert it to positive logic)
STA ORIGIN+3F8H ; to memory mapped I/O.
RET
*****************************************************************
* *
* Xlt tables (sector skew tables) These tables *
* define the sector translation that occurs when mapping CP/M *
* sectors to physical sectors on the disk. There is one skew *
* table for each of the possible sector sizes. *
* *
*****************************************************************
XLT128 DB 0
DB 1,7,13,19,25
DB 5,11,17,23
DB 3,9,15,21
DB 2,8,14,20,26
DB 6,12,18,24
DB 4,10,16,22
XLT256 DB 0
DB 1,2,19,20,37,38
DB 3,4,21,22,39,40
DB 5,6,23,24,41,42
DB 7,8,25,26,43,44
DB 9,10,27,28,45,46
DB 11,12,29,30,47,48
DB 13,14,31,32,49,50
DB 15,16,33,34,51,52
DB 17,18,35,36
xlt512 db 0
db 1,2,3,4,17,18,19,20
db 33,34,35,36,49,50,51,52
db 5,6,7,8,21,22,23,24
db 37,38,39,40,53,54,55,56
db 9,10,11,12,25,26,27,28
db 41,42,43,44,57,58,59,60
db 13,14,15,16,29,30,31,32
db 45,46,47,48
XLT124 DB 0
DB 1,2,3,4,5,6,7,8
DB 25,26,27,28,29,30,31,32
DB 49,50,51,52,53,54,55,56
DB 9,10,11,12,13,14,15,16
DB 33,34,35,36,37,38,39,40
DB 57,58,59,60,61,62,63,64
DB 17,18,19,20,21,22,23,24
DB 41,42,43,44,45,46,47,48
*****************************************************************
* *
* DISK PARAMETER BLOCKS. The following sizes and densities are *
* specified to maintain compatibility with DJ2D CP/M 2.2: *
* 128 bytes, SSSD *
* 256 bytes, SSDD *
* 512 bytes, SSDD *
* 1024 bytes, SSDD *
* 128 bytes, DSDD *
* 256 bytes, DSDD *
* 512 bytes, DSDD *
* 1024 bytes, DSDD *
* *
*****************************************************************
*****************************************************************
* *
* The following DPB defines a diskette for 128 byte sectors, *
* single density, and single sided. *
* *
*****************************************************************
DPB128S DW 26 ;SPT Number of CP/M sectors/track
DB 3 ;BSH Block Shift Factor
DB 7 ;BLM Block Mask
DB 0 ;EXM Extent Mask
DW 242 ;DSM Disk Space Maximum
DW 63 ;DRM Directory Maximum
DB 0C0H ;AL0 Initial Allocation Vectors
DB 0 ;AL1
DW 16 ;CKS Directory Check Size
DW 2 ;OFF Track Offset
DB 00 ;PSH Physical Record Shift factor
DB 00 ;PHM Physical Record Mask
;(Following byte is used only by the BIOS)
DB 1H ;16*((#cpm sectors/physical sector) -1) +
;log2(#bytes per sector/128) + 1 +
;8 if double sided.
*****************************************************************
* *
* The following DPB defines a diskette for 256 byte sectors, *
* double density, and single sided. *
* *
*****************************************************************
DPB256S DW 52 ;CP/M sectors/track
DB 4 ;BSH
DB 15 ;BLM
DB 0 ;EXM
DW 242 ;DSM
DW 127 ;DRM
DB 0C0H ;AL0
DB 0 ;AL1
DW 32 ;CKS
DW 2 ;OFF
DB 00 ;PSH
DB 00 ;PHM
;
DB 12H ;16*((#cpm sectors/physical sector) -1) +
;log2(#bytes per sector/128) + 1 +
;8 if double sided.
*****************************************************************
* *
* The following DPB defines a diskette as 512 byte sectors, *
* double density, and single sided. *
* *
*****************************************************************
DPB512S DW 60 ;CP/M sectors/track
DB 4 ;BSH
DB 15 ;BLM
DB 0 ;EXM
DW 280 ;DSM
DW 127 ;DRM
DB 0C0H ;AL0
DB 0 ;AL1
DW 32 ;CKS
DW 2 ;OFF
DB 00 ;PSH
DB 00 ;PHM
;
DB 33H ;16*((#cpm sectors/physical sector) -1) +
;log2(#bytes per sector/128) + 1 +
;8 if double sided.
*****************************************************************
* *
* The following DPB defines a diskette as 1024 byte sectors, *
* double density, and single sided. *
* *
*****************************************************************
DP1024S DW 64 ;CP/M sectors/track
DB 4 ;BSH
DB 15 ;BLM
DB 0 ;EXM
DW 299 ;DSM
DW 127 ;DRM
DB 0C0H ;AL0
DB 0 ;AL1
DW 32 ;CKS
DW 2 ;OFF
DB 00 ;PSH
DB 00 ;PHM
;
DB 74H ;16*((#cpm sectors/physical sector) -1) +
;log2(#bytes per sector/128) + 1 +
;8 if double sided.
*****************************************************************
* *
* The following DPB defines a diskette for 128 byte sectors, *
* single density, and double sided. *
* *
*****************************************************************
DPB128D DW 52 ;CP/M sectors/track
DB 4 ;BSH
DB 15 ;BLM
DB 1 ;EXM
DW 242 ;DSM
DW 127 ;DRM
DB 0C0H ;AL0
DB 0 ;AL1
DW 32 ;CKS
DW 2 ;OFF
DB 00 ;PSH
DB 00 ;PHM
;
DB 9H
*****************************************************************
* *
* The following DPB defines a diskette as 256 byte sectors, *
* double density, and double sided. *
* *
*****************************************************************
DPB256D DW 104 ;CP/M sectors/track
DB 4 ;BSH
DB 15 ;BLM
DB 0 ;EXM
DW 486 ;DSM
DW 255 ;DRM
DB 0F0H ;AL0
DB 0 ;AL1
DW 64 ;CKS
DW 2 ;OFF
DB 00 ;PSH
DB 00 ;PHM
;
DB 1AH
*****************************************************************
* *
* The following DPB defines a diskette as 512 byte sectors, *
* double density, and double sided. *
* *
*****************************************************************
DPB512D DW 120 ;CP/M sectors/track
DB 4 ;BSH
DB 15 ;BLM
DB 0 ;EXM
DW 561 ;DSM
DW 255 ;DRM
DB 0F0H ;AL0
DB 0 ;AL1
DW 64 ;CKS
DW 2 ;OFF
DB 00 ;PSH
DB 00 ;PHM
;
DB 3BH
*****************************************************************
* *
* The following DPB defines a diskette as 1024 byte sectors, *
* double density, and double sided. *
* *
*****************************************************************
DP1024D DW 128 ;CP/M sectors/track
DB 4 ;BSH
DB 15 ;BLM
DB 0 ;EXM
DW 599 ;DSM
DW 255 ;DRM
DB 0F0H ;AL0
DB 0 ;AL1
DW 64 ;CKS
DW 2 ;OFF
DB 00 ;PSH
DB 00 ;PHM
;
DB 7CH
*****************************************************************
* *
* DISK PARAMETER HEADERS (for four drives) *
* *
*****************************************************************
DPZERO DW 0 ;XLT Address of translation table (filled
; in by setdrv)
DW 0,0,0,0 ;-0- BDOS Scratch Area
DB 0
DB 0 ;MF Media Flag
DW 0 ;DPB Address of DPB (filled in by setdrv)
DW CSV0 ;CSV Directory check vector
DW ALV0 ;ALV Allocation vector
DW DIRBCB ;DIRBCB Directory Buffer Control Block
DW 0FFFFH ;DTABCB Data Buffer Control Block
DW 0FFFFH ;HASH Directory Hashing Table
DB 0 ;HBANK Bank number of Hash Table
;
DPONE DW 0
DW 0,0,0,0
DB 0
DB 0
DW 0
DW CSV1
DW ALV1
DW DIRBCB
DW 0FFFFH
DW 0FFFFH
DB 0
;
DPTWO DW 0
DW 0,0,0,0
DB 0
DB 0
DW 0
DW CSV1
DW ALV1
DW DIRBCB
DW 0FFFFH
DW 0FFFFH
DB 0
;
DPTHRE DW 0
DW 0,0,0,0
DB 0
DB 0
DW 0
DW CSV1
DW ALV1
DW DIRBCB
DW 0FFFFH
DW 0FFFFH
DB 0
*****************************************************************
* *
* Directory Buffer Control Block *
* *
*****************************************************************
DIRBCB: DB 0FFH ;DRV Drive number
DB 00,00,00 ;REC# Record position in buffer
DB 00 ;WFLG Buffer Written flag
DB 00 ;00 BDOS scratch byte
DW 0000 ;TRACK Buffer contents' phys track
DW 0000 ;SECTOR Buffer contents' phys sector
DW DIRBUF ;BUFFAD Buffer address
*****************************************************************
* *
* Miscellaneous ram locations used by the BIOS *
* *
*****************************************************************
CPMSEC DB 0 ;CP/M sector #
CPMDRV DB 0 ;CP/M drive #
CPMTRK DB 0 ;CP/M track #
TRUESEC DB 0 ;Disk Jockey sector that contains CP/M sector
BUFDRV DB 0 ;Drive that buffer belongs to
BUFTRK DB 0 ;Track that buffer belongs to
BUFSEC DB 0 ;Sector that buffer belongs to
BUFFER DS 1024 ;Maximum size buffer for 1K sectors
*****************************************************************
* *
* Allocation Vectors (for four drives) *
* Each vector requires 2 bits for each block on the drive *
* *
*****************************************************************
ALV0 DS 150 ;Allocation vector for drive A
ALV1 DS 150 ;Allocation vector for drive B
ALV2 DS 150 ;Allocation vector for drive C
ALV3 DS 150 ;Allocation vector for drive D
*****************************************************************
* *
* Checksum Vectors (for four drives) *
* Each vector requires 1 bit for every four directory entries *
* *
*****************************************************************
CSV0 DS 64 ;Directory check vector for drive A
CSV1 DS 64 ;Directory check vector for drive B
CSV2 DS 64 ;Directory check vector for drive C
CSV3 DS 64 ;Directory check vector for drive D
*****************************************************************
* *
* Directory Buffer *
* *
*****************************************************************
DIRBUF DS 128
;
END
