;
;
;
; S E L E C T D I S K D R I V E
;
; Select the disk drive for subsequent disk transfers and
; return the appropriate DPB address. This routine
; diverges from the normal CP/M implementation of just
; saving the disk selection value until the transfer is
; performed. This divergence is required because floppy
; disks are a removable media and come in more than one
; format. This routine determines the correct format and
; initializes the DPH with the appropriate values for the
; format type.
;
; ENTRY C = disk delection value.
; DE and 1 = 0, must determine disk type.
; = 1, drive type has been determined.
;
; EXIT HL = 0, if drive not selectable.
; HL = DPH address if drive is selectable.
;
; DPH is intialized for the appropriate floppy
; disk format.
SELDSK:
MOV A,C
CPI NDSK
JNC SELD2 ;If invalid drive
PUSH D ;Save drive selection mask
MVI B,0
PUSH B ;Save drive number
CALL HOME ;Flush buffers
POP B ;Restore disk selection
MOV A,C
STA SEKDSK ;Save disk selection code
LXI H,DTYPE
DAD B
DAD B
MOV A,M
PUSH H ;Save pointer to Class 6, op code 0
MOV L,C ;Compute DPH address
MOV H,B
DAD H ;*2
DAD H ;*4
DAD H ;*8
DAD H ;*16
LXI D,DPH
DAD D ;HL = DPH address
STA SEKTYP ;Save disk type
XTHL ;Get pointer to Class 6, op code 0
; and save DPH address.
ANI TYPEFPY+TYPEMIN ;Floppy?
JZ SELD1
SELD0:
INX H ;Yes. Get Class 6, op code 0 type
MOV A,M
STA CIOFS+5
LXI H,DSKMSK ;Get LUN
DAD B
MOV A,M
STA CIOFS+1
STA CIOPB+1 ;Set for error handling
LXI H,CIOFS ;Set track format code
CALL EXEC
CZ WAITF
CALL SFINAL ;Check for errors
JZ SELD1
POP H ;Error. Restore stack
POP D
JMP SELD2
SELD1:
POP H ;Restore DPH address
POP D ;Restore Drive selction mask
RET
SELD2: LXI H,0
LDA CDISK
SUB C
RNZ ;If default drive not in error
STA CDISK
RET
CIOFS: DB FSCMD,0,0,0,0,0
;
; H O M E
;
; Return disk to home. This routine sets the track number
; to zero. The current host disk buffer is flushed to the
; disk.
HOME:
CALL FLUSH ;Flush host buffer
XRA A
STA HSTACT ;Clear host active flag
STA UNACNT ;Clear sector count
STA SEKTRK
STA SEKTRK+1
RET
;
;
;
;
; S E T T R A C K.
;
; Set track number. The track number is saved for later
; use during a disk transfer operation.
;
; ENTRY BC = track number.
SETTRK:
MOV L,C
MOV H,B
SHLD SEKTRK
LHLD UNATRK
MOV A,L
XRA C
MOV C,A
MOV A,H
XRA B
ORA A
RZ ;If same track
; JMP CUNACT
;
;
;
;
;
;
;
;
; Clear Unallocated block count (force pre-reads).
CUNACT: XRA A ;A = 0
STA UNACNT ;Clear unallocated block count
RET
;
;
;
;
; Set the sector for later use in the disk transfer. No
; actual disk operations are perfomed.
;
; Entry BC = sector number.
SETSEC: MOV A,C
STA SAVSEC ;sector to seek
RET
;
;
;
;
; Set Disk memory address for subsequent disk read or
; write routines. This address is saved in DMAADR until
; the disk transfer is performed.
;
; ENTRY BC = Disk memory address.
;
; EXIT DMAADR = BC.
SETDMA:
MOV H,B
MOV L,C
SHLD DMAADR
RET
;
;
;
;
; Translate sector number from logical to physical.
;
; ENTRY DE = 0, no translation required.
; DE = translation table address.
; BC = sector number to translate.
;
; EXIT HL = translated sector.
SECTRN:
LDA UNASEC
CMP C
CNZ CUNACT ;If sectors do not match
MOV A,C
STA LOGSEC
MOV L,C
MOV H,B
MOV A,D
ORA E
RZ ;If no translation
DAD D
MOV L,M
MVI H,0
RET
; B o o t C P / M f r o m d i s k.
;
; The WBOOT entry point gets control when a warm start
; occurs, a ^C from the console, a jump to BDOS (function
; 0), or a jump to location zero. The WBOOT routine reads
; the CCP and BDOS from the apprpriate Hard disk sectors.
; WBOOT must also re-initialize locations 0,1,2 and 5,6,7.
; The WBOOT routines exits with the C register set to the
; appropriate drive selection value. The exit address
; is to the CCP routine.
LXI H,CIOBT
LXI D,CCP
CALL RDISK ;Read data into memory
MOV A,C
ANI FERR
JNZ WBOOT ;If errors retry
GOCPM: LXI H,DBUF
SHLD DMAADR ;Set default address
MVI A,0C3h ;Store jumps in low memory
STA 0
STA 5
LXI H,BIOS+3
SHLD 1
LXI H,BDOS
SHLD 6
LDA CDISK
MOV C,A
JMP CCP ;Go to CPM
CIOBFS: DB FSCMD,0,0,0,0,0
CIOBT: DB RDCMD ;Command = read
BTLUN: DB 0 ;Physical drive = hard disk
DB 0
BTSLA0:
DB 0
BTNSEC: DB 0 ;# CCP and BDOS sector
DB 0
; Read a CP/M 128 byte sector.
;
; EXIT A = 0, successful read operation.
; A = 1, unsucessful read operation.
READ: CALL CHKBKD ;Check for blocked drive
JC FREAD ;If non-blocked transfer
XRA A ;Set flag to force a read
STA UNACNT ;Clear sector counter
CALL FILL ;Fill buffer with data
POP H
POP D
MVI C,128
CALL MOVDTA ;Move 128 bytes
LDA ERFLAG
ORA A
RZ
XRA A
STA HSTACT
ORI 001h
RET
;
;
;
;
; Write the selected 128 byte CP/M sector.
;
; ENTRY C = 0, write to a previously allocated block.
; C = 1, write to the directory.
; C = 2, write to the first sector of unallocated
; data block.
;
; EXIT A = 0, write was successful.
; A = 1, write was unsucessful.
WRITE: CALL CHKBKD ;Check for blocked drive
JC FWRITE ;If non-blocked transfer
MOV A,C ;Move write type
STA WRTYPE
CPI WRUAL
JNZ WRIT1 ;If not write to unallocated
MVI A,HSTSIB-1 ;Set new unallocated parameters
STA UNACNT
LHLD SEKTRK
SHLD UNATRK ;UNATRK = SEKTRK
LDA LOGSEC
INR A
JMP WRIT2
WRIT1: LDA UNACNT
ORA A
JZ WRIT3 ;If no sectors left in block
DCR A
STA UNACNT
LDA UNASEC ;Increment unallocated sectors
INR A
CPI CPMSPT
JNZ WRIT3 ;If not new track
LHLD UNATRK
INX H
SHLD UNATRK ;UNATRK = UNATRK+1
XRA A ;A = 0
WRIT2: STA UNASEC
MVI A,0FFh
WRIT3: CALL FILL
POP D
POP H
MVI C,128
CALL MOVDTA ;Move 128 bytes
MVI A,1
STA HSTWRT ;HSTWRT = 1
LDA ERFLAG
ORA A
RNZ ;If any errors occurred
LDA WRTYPE ;write type
CPI WRDIR ;to directory?
CZ FLUSH ;Force write of directory
LDA ERFLAG
ORA A
RET
;
;
;
;
; FILL - fill host buffer with approprite host sector.
;
; ENTRY A = 0, Read required if not in buffer.
; 0therwise read not required.
;
; EXIT On exit the stack will contain the following
; values:
; POP x ;x = host record address.
; POP y ;y = caller's buffer address.
FILL: STA RDFLAG ;Save read flag
LHLD DMAADR
XTHL ;Set caller's buffer address
PUSH H
LDA ACTTYP ;Get physical sector size
ANI TYPESEC
RAR
MOV B,A
MOV C,A
XRA A ;Generate sector mask
FILL0:
STC
DCR B
JM FILL1
RAL
JMP FILL0
FILL1:
MOV B,A
LDA SEKSEC ;Compute relative record number
ANA B
LXI H,HSTBUF ;Compute host record address
LXI D,128
FILL2:
DCR A
JM FILL3
DAD D
JMP FILL2
FILL3:
XTHL ;Put buffer address of record on stack
PUSH H
LDA SEKSEC ;Convert to physical sector numver
FILL4:
DCR C
JM FILL5
ANA A ;Carry = 0
RAR
JMP FILL4
FILL5:
STA SEKSEC
LXI H,HSTACT ;host active flag
MOV A,M
MVI M,1 ;always becomes 1
ORA A
JZ FILL6 ;If host buffer inactive
LXI H,HSTDSK
CALL CMPSEK ;Compare HST with SEK
RZ ;If everything same
CALL FLUSH ;Flush host buffer
FILL6: LHLD SEKDSK ;Move disk and type
SHLD HSTDSK
SHLD ACTDSK
LHLD SEKTRK
SHLD HSTTRK
SHLD ACTTRK
LDA SEKSEC
STA HSTSEC
STA ACTSEC
LDA RDFLAG
ORA A
RNZ ;If no read required
FREAD: MVI A,RDCMD ;Set read command
LXI H,RDISK ;Set transfer routine address
JMP FINAL
;
;
;
;
; FLUSH - Write out active host buffer onto disk.
FLUSH:
LXI H,HSTWRT
MOV A,M
ORA A
RZ ;If host buffer already on disk
MVI M,0
LHLD HSTDSK ;Move disk and type
SHLD ACTDSK
LHLD HSTTRK
SHLD ACTTRK
LDA HSTSEC
STA ACTSEC
FWRITE: MVI A,WTCMD ;Set write command
LXI H,WDISK ;Set transfer routine address
; JMP FINAL
;
;
;
;
; F I N A L -- Preform final tranfer processing.
;
; ENTRY A = Command.
; HL = transfer routine address.
FINAL:
CALL SETUP
SFINAL: ;Called from SELDSK
IF I696
LXI H,NMSG2 ;Set message address
ORA A
JNZ FNL3 ;If message byte is non-zero
LXI H,NMSG ;Set message address
MOV A,B
ANI MSSG
JZ FNL3 ;If message bit zero
ENDIF
MOV A,C
ANI FERR ;mask for errors
STA ERFLAG
RZ ;If no errors
MOV A,C
ANI CERR+TERR
LXI H,CERMSG
PUSH B
CNZ PRINT ;If controller error
POP B
LXI H,TOMSG ;Check for timeout
MOV A,C
ANI TERR
JNZ FNL3
FNL1: MOV A,C
ANI PERR
JZ FNL2 ;If no parity errors
LXI H,PERMSG
JMP FNL3
FNL2: LDA CIOPB+1
ANI 0E0H
STA CIOER+1
LXI H,CIOER
LXI D,TEMPBF
CALL RDISK
LXI H,TYPMSG ;Issue type message
CALL PRINT
LDA TEMPBF ;Get type
RRC
RRC
RRC
RRC
ANI 3
CALL OHN ;Output hex nibble
LXI H,CODMSG
CALL PRINT ;Issue code message
LDA TEMPBF ;Get code
ANI 0Fh
CALL OHN ;Output hex nibble
LXI H,ENDMSG
FNL3: CALL PRINT
ORI 1
STA ERFLAG
RET
CIOER: DB ESCMD,0,0,0,0,0 ;Request Error code
CERMSG: DB CR,LF,'Controller error',0
TYPMSG: DB ' Type <',0
CODMSG: DB '>, Code <',0
ENDMSG: DB '>',CR,LF,0
TOMSG: DB ' Timeout',0
IF I696
NMSG: DB CR,LF,'No message bit',0
NMSG2: DB CR,LF,'Message byte non-zero',0
ENDIF
PERMSG: DB CR,LF,'Parity error.',0
;
;
;
;
; S E T U P - Setup the CIOPB area.
;
; ENTRY A = Command.
; HL = transfer routine address.
SETUP:
PUSH H ;Set next phase address
STA CIOPB+0 ;Set command
LXI D,0
LDA ACTDSK ;Get LUN
MOV E,A
LXI H,DSKMSK ;Get LUN
DAD D
MOV C,M
LXI H,DSKOFF
DAD D
DAD D
DAD D
MOV A,M
INX H
MOV D,M
INX H
MOV E,M
ORA C ;LUN in bits 5-7
MOV C,A
SETP1: PUSH B ;Save unit selection
LHLD ACTTRK ;Get track number
MOV B,H ;BC = 1*TRK
MOV C,L
DAD H ;HL = 2*TRK
DAD B ;HL = (2+1)*TRK = 3*TRK
DAD H ;HL = 6*TRK
DAD H ;HL = 12*TRK
DAD B ;HL = (12+1)*TRK = 13*TRK
DAD H ;Hl = 26*TRK
LDA ACTSEC
MVI B,0
MOV C,A
DAD B ;HL = 26*TRK+SEC
POP B ;Restore BC
XRA A ;A = 0
DAD D
ADC C
XCHG
LXI H,CIOPB+1
MOV M,A
INX H
MOV M,D
INX H
MOV M,E
INX H
MVI M,1 ;Read one sector
INX H
MVI M,00h ;Force ECC correction
LHLD BUFADR
XCHG
LXI H,CIOPB
RET ;Dispatch to routine
; Disk I/O Routines
;
;
IF I696
; E X E C
EXEC: MVI B,BUSY ;Wait for not busy.
MVI C,BUSY and (not BUSY)
CALL WAITM
RNZ
MVI A,SLCT ;Alert controller
OUT DIO+1
EXEC1:
MOV C,B ;Wait for controller busy
CALL WAITM
RNZ
MVI A,DODTA ;Enable data in
OUT DIO+1
EXEC2: IN DIO+2 ;Get status
XRI 0FFh
JM EXEC2 ;If not requesting next byte
ANI CMND+DIROUT
JNZ EXEC3 ;If CMND or DIROUT false
MOV A,M
INX H
OUT DIO ;Send byte from command buffer
JMP EXEC2
EXEC3: CMP A ;Z:=1
RET
;
;
;
;
; WDISK - Output from memory buffer.
; ENTRY: HL = COMMAND BUFFER ADDRESS
; DE = DATA BUFFER ADDRESS
;
WDISK: CALL EXEC ;Output command
RNZ ;Return if timeout
WDISK1: IN DIO+2 ;Read status
ORA A
JP WDISK1 ;If request is present
ANI CMND
JNZ GCMPS ;If done with transfer
LDAX D ;Get the data byte
OUT DIO
INX D ;Advance buffer address
JMP WDISK1
;
;
;
;
; RDISK - Input to memory buffer.
;
; Entry: HL = command buffer address
; DE = data buffer address
RDISK: CALL EXEC
RNZ ;Return if timeout
RDISK1: IN DIO+2 ;Read status
ORA A
JP RDISK1 ;If request is present
ANI CMND
JNZ GCMPS
IN DIO
STAX D
INX D
JMP RDISK1
;
;
;
;
; WAITF - Wait for function to complete.
WAITF: MVI B,REQ+CMND ;Wait for both REQ and CMND
MOV C,B
CALL WAITM
RNZ
;
; Get completion status.
GCMPS: IN DIO ;Get completion status
MOV C,A
GCMP1: IN DIO+2
ORA A
JP GCMP1 ;If REQ not set
MOV B,A
IN DIO ;Get message byte
RET
ENDIF
;
;
;
;
IF I796
; EXEC - Output the command
;
; Enter: HL is the command buffer address
; DE - data transfer address.
EXEC:
MOV A,E ;Output DMA address
OUT DIO+2
MOV A,D
OUT DIO+3
MOV A,L
OUT DIO+4
MOV A,H
OUT DIO+5
MVI A,0
OUT DIO+6
OUT DIO+7
OUT DIO
CMP A ;Z:=1
RET
; Disk read/write
;
; Entry: same as EXEC
;
RDISK:
WDISK: CALL EXEC
RNZ ;Return if timeout
; WAITF - Wait until transfer done
;
; Enter: none
; Exit: when transfer completed
WAITF: MVI B,CMDDON ;Wait for CMDDON
MOV C,B
CALL WAITM
RNZ ;Return if timeout
;
; GCMPS - Get completion status
;
; Enter: none
; Exit: Status in C
GCMPS: IN DIO+1
MOV C,A
RET
ENDIF
; WAITM - Wait for controller with timeout
;
; Entry: B=Status mask
; C=Status value
; Exit: Z=1 if OK, else timeout with A=C=TERR
;
WAITM:
PUSH D ;Save D
PUSH H
LXI H,138 ;Two minute timeout
LXI D,0 ;Max wait @4MHZ is 868 ms
WAITML:
IF I696
IN DIO+2
ENDIF
IF I796
IN DIO
ENDIF
ANA B ;Mask wait bits
CMP C ;Check value
JZ WAITM1
DCX D ;Not ready. Decrement time
MOV A,D
ORA E
JNZ WAITML
DCX H
MOV A,H
ORA L
JNZ WAITML
MVI B,0 ;Timeout
MVI A,TERR
ORA A
WAITM1:
POP H
POP D ;Restore D
MOV C,A ;Return status in C
RET
; MOVDTA - Move data in memory.
;
; ENTRY C = number of bytes to move
; DE = destination address.
; HL = source address.
MOVDTA:
MOV A,M ;source character
STAX D ;to dest
INX H
INX D
DCR C ;loop 128 times
JNZ MOVDTA ;If transfer not complete
RET
;
;
;
;
; Check blocked disk transfer.
;
; EXIT Cbit set, unblocked device.
; Cbit clear, blocked device.
CHKBKD:
XRA A
STA ERFLAG ;Clear error flag
LDA SEKTYP
MOV H,A
ANI TYPESEC
MOV A,H
JZ CBKD2 ;If not blocked device
ANI TYPEFPY+TYPEMIN
MOV A,H
JZ CBKD1 ;If hard disk
CBKD0:
PUSH H
LHLD SEKTRK
MOV A,H
ORA L
POP H
MOV A,H
JNZ CBKD1
ANI NOT TYPESEC AND 0FFh ;Non-blocked
JMP CBKD2
CBKD1:
STA ACTTYP
LXI H,HSTBUF
SHLD BUFADR
MVI A,BXADR ;BIOS extended address
STA BUFADE
LDA SAVSEC
STA SEKSEC
XRA A ;Clear carry flag
RET
SETACT: LDA SEKTYP
CBKD2: STA ACTTYP ;Set actual disk type
LHLD DMAADR
SHLD BUFADR
LDA DMAADE
STA BUFADE
LDA SEKDSK
STA ACTDSK
LHLD SEKTRK
SHLD ACTTRK
LDA SAVSEC
STA ACTSEC
STC ;Set carry flag
RET
;
;
;
;
; Utility subroutine for 16-bit compare
CMPSEK:
LXI D,SEKDSK
MVI C,SEKSEC-SEKDSK+1
CMPS1: LDAX D ;low byte compare
CMP M
RNZ ;If not the same
INX D
INX H
DCR C
JNZ CMPS1 ;If not all checked
RET
;
;
;
;
; Output hex nibble.
OHN: ADI 90h
DAA
ACI 40h
DAA
MOV C,A
JMP CONOUT
;
;
;
;
; Print message terminated by zero byte.
;
; ENTRY HL -> message buffer, terminated by zero.
;
; EXIT HL -> zero byte.
; A = 0.
; Z bit set.
;
; Destroys only HL, Flags, and A registers.
PRINT: MOV A,M ;Get a character
ORA A
RZ ;If zero the terminate
INX H
PUSH B
MOV C,A
CALL CONOUT ;Output to the console
POP B
JMP PRINT
; Physical data buffer address ((DMAADR) or HSTBUF)
HSTACT: DB 0 ;host active flag
HSTWRT: DB 0 ;host written flag
UNACNT: DB 0 ;unalloc rec CNT
UNATRK: DW 0 ;Track
UNASEC: DB CPMSPT+1 ;Sector
LOGSEC DB 0 ;Logical sector
