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Digital-Research-Source-Code/CPM OPERATING SYSTEMS/CPM 86/CONCURRENT/CCPM-86 3.1 SOURCE/D10/LBIOS.A86
Sepp J Morris 31738079c4 Upload 
Digital Research
2020-11-06 18:50:37 +01:00

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title 'Concurrent CP/M Loader BIOS'
;*******************************************************
; Last Modification: 02/16/84
;
; L B I O S - 8 6
; ======================
;
; Concurrent CP/M Loader I/O System
; for
; CompuPro Computer System
;
; Separate Code and Data:
; -----------------------
; The code segment is separate from the data
; segment. The code is ORG'd at 0000h and the
; data is ORG'd at 0180h relative to the System
; Data Area.
;
; high +---------------------+
; | Ldr Program Data |
; + - - - - - - - - - - +
; | Ldr BIOS Data |
; +---------------------+ <- 0180h
; | Ldr BDOS Data |
; +---------------------+ <- 0000h
; +---------------------+
; | Ldr Program Code |
; + - - - - - - - - - - +
; | Ldr BIOS Code |
; +---------------------+ <- 0000h
; +---------------------+
; | Ldr BDOS Code |
; low +---------------------+ <- 0000h
;
;*******************************************************
;
; The following commands are used to generate CPMLDR.SYS
; RASM86 LBIOS
; RASM86 LPROG
; LINK86 LBIOS3.SYS = LBIOS,LPROG [DATA[ORIGIN[0180]]]
; GENLDR [nnnn]
;
; The following commands are used to generate the
; boot tracks image BOOTTRKS
; SID86
; #RDSKBOOT.SYS ;strips header and
; #WBOOT,180,37F ;default base page
; PIP BOOTTRKS = BOOT[O],CPMLDR.SYS[O]
;
;*******************************************************
;
; Register usage for BIOS interface routines:
;
; Entry: AL = function number (in entry)
; CX = first parameter
; DX = second parameter
; DS = ES = system data segment (in entry and init)
; Exit: AX = return or BIOS error code
; BX = AX (in exit)
; DS = ES = preserved through call
; SS,SP must also be preserved
; CX,DX,SI,DI,BP can be changed by the BIOS
;
;*******************************************************
;
; Loader IOS Coding Conventions
;
;*******************************************************
;
; @ as the first character of a symbol denotes
; a public variable
;
; ? as the first character of a symbol denotes
; a public label
;
; All labels, and code are in lower-case
; for easier reading.
;
; All immediate values (literals) are in uppercase.
;
; Fields within data structures have leading
; letters followed by an underbar and the field
; name. The data structures defined are:
;
; BH_ - BIOS Header
; DPB_ - Disk Parameter Block
; DPH_ - Disk Parameter Header
; IOPB_ - I/O Parameter Block
;
; Underscores are used for readiablity otherwise
; Symbols, code mnemonics, registers are in all upper-case
; within comments to distinquish them from the code.
;
;*******************************************************
;
; Character I/O Equates
;
;*******************************************************
; CompuPro System Support serial definitions
SS_BASE equ 050h ;base address
SS_MODE equ SS_BASE+0Eh ;CompuPro System Support mode
SS_COMMAND equ SS_BASE+0Fh ;CompuPro System Support command
SS_STATUS equ SS_BASE+0Dh ;CompuPro System Support status
SS_DATA equ SS_BASE+0Ch ;CompuPro System Support data
SS_TRANS_READY equ 00000001b ;System Support transmit buffer empty
SS_RECV_READY equ 00000010b ;System Support data available
SS_DSR equ 10000000b ;System Support data set ready
;*******************************************************
;
; Disk Parameter Header Equates
;
;*******************************************************
;
; +-----+-----+-----+-----+-----+------+-----+-----+
; 00h | XLT | | DOPEN| |
; +-----+-----+-----+-----+-----+------+-----+-----+
; 08h | DPB | CSV | ALV | DIRBCB |
; +-----+-----+-----+-----+-----+------+-----+-----+
; 10h | DATBCB | HSHTBL | INIT | LOGIN |
; +-----+-----+-----+-----+-----+------+-----+-----+
; 18h | READ | WRITE | UNIT| CHNNL| FCNT|
; +-----+-----+-----+-----+-----+------+-----+
DPH_XLT equ word ptr 0
DPH_DOPEN equ byte ptr 5
DPH_DPB equ word ptr 8
DPH_CSV equ word ptr 10
DPH_ALV equ word ptr 12
DPH_DIRBCB equ word ptr 14
DPH_DATBCB equ word ptr 16
DPH_HSHTBL equ word ptr 18
DPH_INIT equ word ptr 20
DPH_LOGIN equ word ptr 22
DPH_READ equ word ptr 24
DPH_WRITE equ word ptr 26
DPH_UNIT equ byte ptr 28
DPH_CHNNL equ byte ptr 29
DPH_FCNT equ byte ptr 30
;*******************************************************
;
; Disk Parameter Block Equates
;
;*******************************************************
;
; +-----+-----+-----+-----+-----+-----+-----+-----+
; 00h | SPT | BSH | BLM | EXM | DSM | DRM..
; +-----+-----+-----+-----+-----+-----+-----+-----+
; 08h ..DRM | AL0 | AL1 | CKS | OFF | PSH |
; +-----+-----+-----+-----+-----+-----+-----+-----+
; 10h | PHM |
; +-----+
DPB_SPT equ word ptr 0
DPB_BSH equ byte ptr 2
DPB_BLM equ byte ptr 3
DPB_EXM equ byte ptr 4
DPB_DSM equ word ptr 5
DPB_DRM equ word ptr 7
DPB_AL0 equ byte ptr 9
DPB_AL1 equ byte ptr 10
DPB_CKS equ word ptr 11
DPB_OFF equ word ptr 13
DPB_PSH equ byte ptr 15
DPB_PHM equ byte ptr 16
;*******************************************************
;
; Input/Output Parameter Block Definition
;
;*******************************************************
;
; Read and Write disk parameter equates
;
; At the disk read and write entries,
; all disk I/O parameters are on the stack
; and the stack at these entries appears as
; follows:
;
; +-------+-------+
; +14 | DRV | MCNT | Drive and Multi sector count
; +-------+-------+
; +12 | TRACK | Track number
; +-------+-------+
; +10 | SECTOR | Physical sector number
; +-------+-------+
; +8 | DMA_SEG | DMA segment
; +-------+-------+
; +6 | DMA_OFF | DMA offset
; +-------+-------+
; +4 | RET_SEG | BDOS return segment
; +-------+-------+
; +2 | RET_OFF | BDOS return offset
; +-------+-------+
; BP+0 | RET_ADR | Local ENTRY return address
; +-------+-------+ (assumes one level of call
; from ENTRY routine)
;
; These parameters may be indexed and modified
; directly on the stack and will be removed
; by the BDOS after the function is complete
iopb_mcnt equ byte ptr 15[bp]
iopb_drive equ byte ptr 14[bp]
iopb_track equ word ptr 12[bp]
iopb_sector equ word ptr 10[bp]
iopb_dmaseg equ word ptr 8[bp]
iopb_dmaoff equ word ptr 6[bp]
;*******************************************************
;
; Disk I/O Equates
;
;*******************************************************
DPH_FMB equ byte ptr 31 ;floppy mode byte used by driver
;*******************************************************
;
; Floppy Disk Drivers for Qume Drives
; and a DISK 1 Controller Board
;
;*******************************************************
; Floppy mode bits
FM_D_DENSITY equ 0000$0001b
FM_TWO_SIDED equ 0000$0010b
FM_N_MASK equ 0000$1100b
; read/write control string equates for the Intel 8272 FDC
D equ byte ptr 1 ;D stands for the drive and head
; to be used to perform a read/write
C equ byte ptr 2 ;C stands for the current Cylinder
; track number 0 - 76 of the medium
H equ byte ptr 3 ;H stands for head number 0 or 1, as
; specified in ID field
R equ byte ptr 4 ;R stands for the Sector number, which
; will be read or written
N equ byte ptr 5 ;N stands for the number of data bytes
; written in a Sector
EOT equ byte ptr 6 ;EOT stands for the final Sector number
; of a Cylinder
GPL equ byte ptr 7 ;GPL stands for the length of Gap 3
; (spacing between Sectors excluding
; VCO Sync Field)
DTL equ byte ptr 8 ;When N is defined as 00, DTL stands
; for the data length which is going to
; be read out or write into the sector
; Floppy controler port addresses
FD_PORT equ 0C0h ;base port address of DISK1 controller
FDC_S equ FD_PORT ;8272 status register
FDC_D equ FD_PORT + 1 ;8272 data register
D1_DMA equ FD_PORT + 2 ;DISK1 dma addr when write
D1_INTS equ FD_PORT + 2 ;DISK1 interrupt status when read
; Main status register bits
MSTR_RQM equ 1000$0000b ;master status request
MSTR_DIO equ 0100$0000b ;master status direction
MSTR_CB equ 0001$0000b ;command busy status
FDC_INT equ 1000$0000b ;FDC interrupt output is asserted
RQM_DELAY equ 5 ;12us delay count for master status
; Floppy controler function definitions
F_SPEC equ 03h ;specify
F_DSTS equ 04h ;sense drive status
F_RDAT equ 06h ;read data
F_RECA equ 07h ;recalibrate
F_RSTS equ 08h ;sense interrupt status
F_RDID equ 0Ah ;read id
F_SEEK equ 0Fh ;seek
F_MFM equ 0100$0000b ;double density, MFM mode bit
; Floppy retry equate
RETRY_COUNT equ 10
; Floppy disk status field equates
ST0 equ 0 ;status register 0
ST1 equ 1 ;status register 1
ST2 equ 2 ;status register 2
ST_N equ 6 ;result field N
PCN equ 1 ;present cylinder no. result
; Status field bit equates
ST0_INTCODE_MSK equ 1100$0000b
ST0_STRT_NO_END equ 0100$0000b
ST0_SE equ 0010$0000b ;seek end
ST0_NR equ 0000$1000b ;not ready
ST0_UNIT_MASK equ 0000$0011b ;unit mask
ST0_RECAL_MASK equ 1111$1100b
ST0_RECAL_TEST equ 0010$0000b ;seek complete signal
ST0_SEEK_MASK equ 1111$1100b
ST0_VALID_SEEK equ 0010$0000b ;seek complete signal
ST1_EOT_END equ 1000$0000b ;end of cylinder
ST3_READY equ 0010$0000b ;ready signal
ST3_TWO_SIDED equ 0000$1000b ;two sided disk
ST_N_MASK equ 0000$0011b ;N field mask
; Equates for the floppy disk code readability
OK equ 00h
ERROR equ 0FFh
HEAD_BIT equ 0000$0100b
RW_ERROR equ 01h
WR_PROT_ERROR equ 02h
RW_MEDIA_CHANGE equ 0FFh
SELDSK_ERROR equ 0
CYLINDER_2 equ 2
; CCP/M disk control block equates which define the
; disk types and maximum storage capability of each
; disk type.
; CCP/M to host disk constants
CPMSIB equ 1024/128 ;standard sectors in block
FPYSIB equ 2048/128 ;sectors in floppy disk block
S1DSM equ ((77-2)*26)/CPMSIB
S2DSM equ ((77-2)*2*26)/FPYSIB
D1DSM equ ((77-2)*2*26)/FPYSIB
D2DSM equ ((77-2)*2*2*26)/FPYSIB
D3DSM equ ((77-2)*4*15)/FPYSIB
D4DSM equ ((77-2)*2*4*15)/FPYSIB
D5DSM equ ((77-2)*8*8)/FPYSIB
D6DSM equ ((77-2)*2*8*8)/FPYSIB
;*******************************************************
;
; 8259A Programmable Interrupt Controller Equates
;
;*******************************************************
;
; PIC EQUATES: see pages 7-120 -> ... in the 1982 INTEL DATA CATALOG
;
; Interupt Structure
;
; MASTER PIC: IRQ0 =
; IRQ1 = DISK 2
; IRQ2 = interfacer 3 receive ready
; IRQ3 = interfacer 3 transmit ready
; IRQ4 = DISK 1
; IRQ5 =
; IRQ6 =
; IRQ7 = Slave input
;
; SLAVE PIC: IRQ0 =
; IRQ1 = Timer 0 ( tick )
; IRQ2 = Timer 1 ( free )
; IRQ3 = Timer 2 ( free )
; IRQ4 = 9511 svrq
; IRQ5 = 9511 end
; IRQ6 = SS Tx int
; IRQ7 = SS Rx int
DISABLE_INTS equ 0FFh ;mask to turn off all interrupts
NS_EOI equ 20h ;Non specific end of interrupt
MASTER_PIC_PORT equ 50h
SLAVE_PIC_PORT equ 52h
MASTER_ICW_1 equ 15h ;basic operational mode of chip
MASTER_ICW_2 equ 40h ;base of chips interrupt vectors
MASTER_ICW_3 equ 80h ;master/slave map
MASTER_ICW_4 equ 01h ;interrupt response mode
SLAVE_ICW_1 equ MASTER_ICW_1
SLAVE_ICW_2 equ MASTER_ICW_2 + 8
SLAVE_ICW_3 equ 07h ;slave I.D. number
SLAVE_ICW_4 equ MASTER_ICW_4
;*******************************************************
;
; BIOS Kernel Code Publics and Externals
;
;*******************************************************
CSEG
public @sysdat ;force CS over-ride
public ?conout, ?pmsg
extrn ?start:near
;*******************************************************
;
; BIOS Code Header
;
;*******************************************************
org 0000h
jmp init ;I/O system initialization
jmp entry ;I/O system function entry
jmp ?start ;start of loader program
@sysdat rw 1 ;OS Data Segment
;*******************************************************
;
; BIOS Kernel Data Publics and Externals
;
;*******************************************************
DSEG
public @bh_dphtable, @dpha
;*******************************************************
;
; BIOS Data Header
;
;*******************************************************
org 0000h
;use the LINK-86 [data[origin[0180]]] option
;to set the origin of the data segment at 0180h
; disk parameter header offset table
@bh_dphtable dw offset @dpha ;drive A:
;*******************************************************
;
; BIOS Code Segment
;
;*******************************************************
CSEG
;====
init:
;====
; Entry: DS = ES = system data segment
; Exit: DS = ES = preserved through call
cli ;disable interrupts
cld ;set forward direction
; set up the master PIC
mov al,MASTER_ICW_1
out MASTER_PIC_PORT,al
mov al,MASTER_ICW_2 ;interupts start at interupt 40h
out MASTER_PIC_PORT + 1,al
mov al,MASTER_ICW_3 ;only IRQ 7 has a slave attached
out MASTER_PIC_PORT + 1,al
mov al,MASTER_ICW_4 ;Set for 8088 mode
out MASTER_PIC_PORT + 1,al
mov al,DISABLE_INTS ;turn off all interupts for now
out MASTER_PIC_PORT + 1,al
; set up the slave PIC
mov al, SLAVE_ICW_1
out SLAVE_PIC_PORT,al
mov al,SLAVE_ICW_2 ;base of the slave vectors AT 48H
out SLAVE_PIC_PORT + 1,al
mov al,SLAVE_ICW_3 ;slave ID number = 7
out SLAVE_PIC_PORT + 1,al
mov al,SLAVE_ICW_4 ;8088 mode
out SLAVE_PIC_PORT + 1,al
mov al,DISABLE_INTS ;turn off the ints for now
out SLAVE_PIC_PORT + 1,al
sti
; initialize the console on the System Support board
mov al,0EEh ;AL = mode register 1 ,async 16x rate
out SS_MODE,al ;send mode register 1
mov al,07Eh ;AL = mode register 2, internal clock
out SS_MODE,al ;send mode register 2
mov al,00$1$0$0$1$1$1b ;trans. on,dtr low,rec. on,no break,
;...no reset,rts low
out SS_COMMAND,al ;set up command port
; Floppy disk controller initialization.
; Set up the values for the fdc's three internal timers.
; HUT (head unload time) = (0fh * 16ms) [240ms]
; SRT (step rate) = (0fh - 0dh * 1ms increments) [3ms]
; HLT (head load time) = (31H * 2ms) [98ms]
; and it sets up the DMA mode
; ND (non-dma bit) = DMA mode [0]
;
; see pages 41 and 38 of the CompuPro DISK 1 manual
mov bx,offset specify_cmd ;specify command
mov cl,length specify_cmd ;sets up initial fdc counter values
call send_command
mov si,offset signon ;signon message defined in INIT module
call ?pmsg ;print the BIOS signon message
retf
;*******************************************************
;
; BIOS Entry Function Dispatch
;
;*******************************************************
;=====
entry: ; BIOS Entry Point
;=====
; All calls to the BIOS after INIT, enter through this code
; with a CALLF and must return with a RETF.
; Entry: AL = function number
; CX = first parameter
; DX = second parameter
; DS = ES = system data segment
; Exit: AX = BX = return or BIOS error code
; DS = ES = preserved through call
; SS,SP must also be preserved
; CX,DX,SI,DI,BP can be changed by the BIOS
cld ;clear direction flag
xor ah,ah ! shl ax,1 ;index into BIOS function table
mov bx,ax
call functab[bx] ;call BIOS kernel routine
mov bx,ax ;BX = AX
retf
;*******************************************************
;
; BIOS Character Output Routines
;
;*******************************************************
?conout: ;BIOS function 2
;=======
; Entry: CL = character
; Exit: None
in al,SS_STATUS ;get uart status
test al,SS_TRANS_READY ;test if buffer empty
jz ?conout
mov al,cl
out SS_DATA,al
ret
?pmsg: ;Print String
;=====
; Entry: DS:SI = offset of string terminated by 0.
; Exit: None
mov cl,[si] ;get character from buffer
or cl,cl ! jz pmsg_exit ;check for 0 terminater
push si
call ?conout ;output character in CL
pop si
inc si
jmps ?pmsg ;get next character
pmsg_exit:
ret
;*******************************************************
;
; BIOS Disk I/O Routines
;
;*******************************************************
io_seldsk: ;BIOS function 9
;=========
; Entry: CL = disk to be selected
; DL = (Bit 0): 0 if first select
; Exit: AX = 0 if illegal select
; = offset of DPH relative to OS data segment
xor bx,bx
cmp cl,0 ! jne sel_ret ;if not valid drive exit
mov bx,@bh_dphtable ;get DPH from drive table
test dl,1 ! jnz sel_ret ;first time select?
call DPH_LOGIN[bx] ; yes
sel_ret:
mov ax,bx
ret
io_read: ;BIOS function 10
;=======
; Entry: IOPB filled in (on stack)
; Exit: AL = 0 if no error
; = 1 if physical error
; = 0FFH if media density has changed
mov bp,sp ;SS:BP points to IOPB
cmp iopb_drive,0 ! jne ret_error
mov bx,@bh_dphtable ;get DPH address
jmp DPH_READ[bx] ;jump to DPH read routine
ret_error:
mov al,1 ;return error if not valid
ret
io_notimp: ;BIOS function not implemented
;=========
xor ax,ax ;return success
ret
;*******************************************************
;
; Floppy Disk I/O Code Segment
;
;*******************************************************
fd_login: ;Login routine for the floppy disk drive
;========
; This routine figures out
; 1] what kind of floppy is in the drive
; 2] does a recal, homes the head
; 3] saves the floppy mode byte in the DPH.
; 4] sets up the current floppy mode byte.
; 5] sets up the dph's
; 6] returns the addr of the DPH
; NOTES:
; there is a DPB for each of the possible disk configurations.
; 1] SD 128
; 2] DD 256
; 3] DD 512
; 4] DD 1024
; 5-8] same as 1 - 4 with double sided disks.
;
; Entry: BX = DPH offset
; CL = selected disk
; Exit: BX = 0 if illegal select
; = offset of DPH relative to O.S. data segment
push bx
call get_media_type
pop bx ;BX = DPH offset
cmp al,ERROR ! jne fd_1
mov bx,SELDSK_ERROR ;set up the error code for CCP/M
jmps fd_login_exit
fd_1:
mov DPH_FMB[bx],al ;save the current floppy mode byte
; for this drive in the DPH
xor ah,ah ;set up the xlat table addr in DPH
mov di,ax ;save DI for index into DPB table
shr al,1 ! and al,0FEH
mov si,ax
mov ax,xtable[si] ;get the translation table
mov DPH_XLT[bx],ax ;put the xlat table addr in DPH
and di,0FFFEh ;get the proper dpb
mov ax,drv_tbl[di] ;index into the dpb table
mov DPH_DPB[bx],ax ;and put it in the dph
fd_login_exit:
ret ;BX = DPH offset
fd_read: ;Read routine for the floppy disk drive
;=======
; BX = DPH offset
; Exit: AL = 0 if no error
; = 1 if physical error
; = 0FFH if media density has changed
mov al,DPH_FMB[bx] ;get saved floppy mode
mov c_fmb,al ;set current floppy mode byte
mov ax,DPH_XLT[bx] ;get the xlat table
mov xltbl,ax ;save translation table address
mov bx,DPH_DPB[bx] ;get the DPB from the DPH
mov ax,DPB_SPT[bx]
mov maxsec,ax ;save maximum sector per track
mov cl,DPB_PSH[bx]
mov ax,128 ! shl ax,cl ;compute physical record size
mov secsiz,ax ; and save it
cmp iopb_mcnt,0 ! jne rw_1
mov al,1
ret
rw_1:
mov ax,iopb_sector ;is sector < max sector/track
cmp ax,maxsec ! jb same_trk
inc iopb_track ; next track
xor ax,ax
mov iopb_sector,ax ; initialize sector to 0
same_trk:
mov bx,xltbl ;get translation table address
or bx,bx ! jz no_trans ;if xlt <> 0
xlat al ; translate sector number
no_trans:
mov isector,al ;store sector #
mov ax,iopb_track ;get track # from IOPB
mov itrack,ax
mov ax,iopb_dmaoff ;get dma offset from table
mov idmaoff,ax
mov ax,iopb_dmaseg ;get dma segment from IOPB
mov idmaseg,ax
call phys_rw ;call read routine
or al,al ! jnz err_ret ;if error occured return
mov ax,secsiz ;increment dma offset by the
add iopb_dmaoff,ax ; physical sector size
inc iopb_sector ;next sector
dec iopb_mcnt ;decrement multi sector count
jnz rw_1 ;if MCNT <> 0 store next sector dma
xor ax,ax
err_ret:
ret ;return with error code in AL
phys_rw: ;these are the physical drivers for the CompuPro
;-------
; physical read does the actual read from the floppy.
;
; Entry: itrack = the track to read from
; isector = the sector to read from
; idmaoff = the dma offset to read to or from
; idmaseg = the dma segment to read to or from
;
; Exit: AL = 0 if no error
; = 1 if physical error
; = 2 if Read/Only disk
; = 0FFH if media density has changed
mov rw_retries,RETRY_COUNT
rw_retry_lp:
; setup D, C, H, R, N, EOT, GPL, and DTL fields of RW_CMD
mov al,isector ;put sector in the control strings
inc al ;the bdos expects 0 relative sectors
mov (rw_cmd + R),al ;record
mov (rw_cmd + EOT),al ;and the end of track fields
mov al,F_RDAT ;setup for read command
test c_fmb,FM_D_DENSITY ;check if double density
jz rw_not_dd
or al,F_MFM ;yes - set MFM bit
rw_not_dd:
mov rw_cmd,al ;set r/w command in control string
mov al,c_fmb
and al,FM_N_MASK ;get the N value from the mode byte
shr al,1 ! shr al,1 ; and shift the N bit field to the lsbs
mov (rw_cmd + N),al ; then stuff the control string
mov (rw_cmd + DTL),0FFh ;set dtl for all DD operations
cmp al,0 ! jne zero_dtl ;this checks for a SD floppy
mov (rw_cmd + DTL),128 ; set for SD operation
zero_dtl:
xor ah,ah ;get the gpl as per the
mov si,ax ! mov al,gpl_tbl[si] ;N value in the FMB
mov (rw_cmd + GPL),al
mov ax,itrack
test c_fmb,FM_TWO_SIDED
jz ssided
shr ax,1 ;two sided drive
;so seek trk/2 + bit(0)
ssided:
; set the cylinder number for the seek and control string
mov (seek_cmd + C),al ;set up the seek control
mov (rw_cmd + C),al ;now the read control
; set the drive and head
xor al,al ;set the drive
mov (rw_cmd + H),0
test c_fmb,FM_TWO_SIDED
jz side0 ;if double sided
test itrack,1 ;and track is odd
jz side0 ;set the head bit
or al,HEAD_BIT ;set the head bit for the drive field
mov (rw_cmd + H),1 ;set the head field in the RW_CMD
side0:
mov (seek_cmd + D),al ;stuff the seek drive field
mov (rw_cmd + D),al ; and the RW_CMD drive field
call seek ;seek to the desired cylinder
cmp al,ERROR ! je phys_rw_3
; set up the floppy controllers dma address
mov ax,idmaseg ;get the segment
mov cl,4 ! rol ax,cl ;(para to bytes) shift add to offset
mov dx,ax ;save lower 16 bits of paragraph
and al,0Fh ;get upper nibble of paragraph
and dx,0FFF0h
add dx,idmaoff ;add in the offset
adc al,0 ;add carry into upper nibble
;send 24 bits to controler
out D1_DMA,al ;msb
mov al,dh ! out D1_DMA,al
mov al,dl ! out D1_DMA,al ;lsb
mov bx,offset rw_cmd ;send out the command string
mov cl,length rw_cmd
call send_command
call int_wait ;wait for the read
mov bx,offset rw_res ;get the results of the read
mov cl,length rw_res
call get_results
;check the interupt code
mov al,(rw_res + ST0) ;get the interupt code
and al,ST0_INTCODE_MSK ;check for start but no end
cmp al,ST0_STRT_NO_END
jne phys_rw_4 ;due to EOT
mov al,(rw_res + ST1)
cmp al,ST1_EOT_END
jne phys_rw_4
mov al,OK ;good read so exit
jmps p_read_exit
phys_rw_3:
call recalibrate ;recalibrate on seek errors
phys_rw_4:
dec rw_retries
jz phys_rw_err
jmp rw_retry_lp
phys_rw_err:
mov al,RW_ERROR
p_read_exit:
ret
get_media_type: ;determine media type for a disk select
;--------------
; figures out what kind of disk is in the drive specified
; Then it builds the Floppy mode byte(C_FMB)
; It sets the two sided bit, the density bit, and the sector
; size bits (2, 3) if the disk is DD
; Exit: AL = current floppy mode byte (C_FMB)
; AL = ERROR if there was an error
; C_FMB is set
call recalibrate ;recalibrate drive
cmp al,ERROR ;check for a error in recal
je media_type_exit ;return on error
; Put head 0 over cylinder 2 to sample the disk at the start
; of the directory. Track 0 is SD on the CompuPro DD disk.
mov (seek_cmd + D),0
mov (seek_cmd + C),CYLINDER_2
mov fc_retries,RETRY_COUNT ;initialize retry count
fc_retry_lp:
call seek ;seek to cylinder 2
cmp al,ERROR ! jne cylinder_2_now
dec fc_retries ! jnz fc_retry_lp
jmps media_type_exit ;return with error
cylinder_2_now:
mov c_fmb,0 ;set current floppy mode byte to 0
; get the number of sides from the FDD's status byte
test sdst_res,ST3_TWO_SIDED
jz single_sided
or c_fmb,FM_TWO_SIDED ;set two sided field
single_sided:
; resolve the density either SD or DD we should be over cylinder 2
; if the read id for a DD disk fails try a SD disk
mov rd_id_cmd,F_RDID + F_MFM ;set read id for DD
call read_id
jz sec_size
mov rd_id_cmd,F_RDID ;set read id for SD
call read_id
jz f_sel_com
dec fc_retries ! jnz single_sided
mov al,ERROR
jmps media_type_exit
sec_size:
; first set the d_density bit in the c_fmb
; get the sector size from the N field returned by the FDC
or c_fmb,FM_D_DENSITY ;or in the DD bit in the FMB
mov al,(rd_id_res + ST_N) ;get the N field
and al,ST_N_MASK ;mask for validity
shl al,1 ! shl al,1 ;setup mask for C_FMB
or c_fmb,al ;or the mask into the current mode byte
f_sel_com:
mov al,c_fmb
media_type_exit:
ret
sense_drv_stat: ;sense drive status
;--------------
; Exit: AL = OK if drive is ready
; AL = ERROR if the drive is not ready
mov bx,offset sdst_cmd
mov D[bx],0 ;set the drive, head = 0
mov cl,length sdst_cmd
call send_command ;Sense drive status command
mov bx,offset sdst_res
mov cl,length sdst_res
call get_results
; Note:
; the status byte returned by this call has the fdd's
; ready line status bit in it (bit(3))
; if the upper nibble = 2 the door is closed.
; else if the upper nibble = 4 the is open.
xor al,al
test sdst_res,ST3_READY ;make sure the drive is ready
jnz sds_exit
mov al,ERROR
sds_exit:
ret
recalibrate: ;recalibrate drive
;-----------
; Exit: AL = OK if everthing went OK
; AL = ERROR if it could not find the track 0
; or the drive was off line
call sense_drv_stat ;Sense drive status
cmp al,ERROR ! je recal_exit
mov bx,offset recal_cmd
mov D[bx],0 ;stuff the control string
mov cl,length recal_cmd
call send_command ;send the recal command
call int_wait ;wait for the recal to happen
mov al,(sist_res + ST0)
and al,ST0_RECAL_MASK ;get status register 0
cmp al,ST0_RECAL_TEST ; and make sure recal was ok
mov al,OK
je recal_exit
mov al,ERROR
recal_exit:
ret
seek: ;seek sends the seek command to the fdc
;----
; Entry: SEEK_CMD must be set up on the way in
;
; Exit: AL = OK if everthing went OK
; AL = ERROR if it could not find the right track
; or the drive was off line
call sense_drv_stat ;sense drive status
cmp al,ERROR ! je sk_exit
mov bx,offset seek_cmd ;send the seek command
mov cl,length seek_cmd
call send_command
call int_wait ;wait for the seek
mov al,(sist_res + ST0) ;get status register 0
and al,ST0_SEEK_MASK ; and make sure its ok
cmp al,ST0_VALID_SEEK ! jne sk_err_exit
mov al,(seek_cmd + C) ;compare the cylinder we're over
cmp al,(sist_res + PCN) ;to the one we wanted
mov al,OK
je sk_exit
sk_err_exit:
mov al,ERROR
sk_exit:
ret
read_id:
;-------
; read ID expects the control byte set up before it is called.
; Entry: RD_ID_CMD (read ID control string set up)
; Exit: Z flag set if it could read an ID
; Z flag reset if the drive was not ready
mov bx,offset rd_id_cmd
mov D[bx],0 ;set the drive, head = 0
mov cl,length rd_id_cmd
call send_command ;send the read id command
call int_wait ;wait for the read
mov bx,offset rd_id_res ;get the results
mov cl,length rd_id_res
call get_results
mov al,rd_id_res + ST0 ;get the results
and al,ST0_INTCODE_MSK ;mask for the interupt code
cmp al,OK ;set Z flag if no error
ret
send_command: ;send command to 8272
;------------
; Entry: BX = address of the command string
; CL = the length of the command string
in al,FDC_S
test al,MSTR_CB ! jnz send_command
xor ch,ch
cli
snd_cmd1:
mov al,RQM_DELAY ;must delay 12us before polling
snd_cmd2: ;FDC status to insure valid results
dec al ! jnz snd_cmd2
snd_cmd3:
in al,FDC_S ;get master status from 8272
test al,MSTR_RQM ! jz snd_cmd3
test al,MSTR_DIO ! jnz snd_cmd3
mov al,[bx] ! out FDC_D,al ;send command string to 8272
inc bx
loop snd_cmd1 ;next byte of command string
sti
ret
get_results: ;get results form 8272
;-----------
; Entry: CL = number of bytes to expect from the fdc
; BX = addr of where to put the results
; Exit: the location starting where BX was pointing
; for a length of CX will have the results from the
; fdc result phase
in al,FDC_S
test al,MSTR_CB ! jz get_results
xor ch,ch
get_res1:
mov al,RQM_DELAY ;must delay 12us before polling
get_res2: ;FDC status to insure valid results
dec al ! jnz get_res2
get_res3:
in al,FDC_S ;get master status from 8272
test al,MSTR_RQM ! jz get_res3
test al,MSTR_DIO ! jz get_res3
in al,FDC_D ;get the result status
mov [bx],al ! inc bx
loop get_res1
ret
int_wait: ;interupt wait
;--------
; this routine does a flag wait on the fdc operation.
push bp
int_w1:
in al,D1_INTS ;wait for FDC interrupt to be asserted
test al,FDC_INT ! jz int_w1
; check the direction of data xfer from the FDC's main status port
flint_lp:
in al,FDC_S ;wait for the fdc to become ready
test al,MSTR_RQM ! jz flint_lp ; for data xfer
test al,MSTR_DIO ;if the fdc want to send us data,
jnz fdc_to_processor ; it must be our expected status
;the fdc is expecting a command,
; so query the interrupt status
; Note:
; neither the recalibrate or the seek commands have
; a result phase. Therefore it is mandatory to issue the
; rdcsist command to properly terminate these commands.
; See the 8272 spec sheet for the details.
fdcsist:
in al,FDC_S
test al,MSTR_CB ! jnz fdcsist
fdcsist1:
in al,FDC_S ;poll the fdc to be ready for data com
test al,MSTR_RQM ! jz fdcsist1
test al,MSTR_DIO ! jnz fdcsist1
mov al,F_RSTS ! out FDC_D,al ;send sense interrupt status command
mov bx,offset sist_res
mov cl,length sist_res ;get the two byte result from the
call get_results ;fdc
fdc_to_processor:
pop bp
ret
;*******************************************************
;
; BIOS Data Segment
;
;*******************************************************
DSEG
; BIOS Function Table
functab dw io_notimp ; 0 - console status
dw io_notimp ; 1 - console input
dw io_notimp ; 2 - console output
dw io_notimp ; 3 - list output status
dw io_notimp ; 4 - list output
dw io_notimp ; 5 - aux input
dw io_notimp ; 6 - aux output
dw io_notimp ; 7 - CCP/M function
dw io_notimp ; 8 - CCP/M function
dw io_seldsk ; 9 - select disk
dw io_read ;10 - read sector
dw io_notimp ;11 - write sector
dw io_notimp ;12 - flush buffers
dw io_notimp ;13 - CCP/M function
dw io_notimp ;14 - char. device init
dw io_notimp ;15 - console output status
dw io_notimp ;16 - aux input status
dw io_notimp ;17 - aux output status
signon db 13,10
db 'Concurrent CP/M CompuPro Loader IOS',13,10,0
;*******************************************************
;
; Floppy Disk I/O Data Segment
;
;*******************************************************
imcnt db 0
itrack dw 0
isector db 0
idmaoff dw 0
idmaseg dw 0
; sides density bytes/sec
drv_tbl dw dpbs1 ;ss,sd, 128
dw dpbs2 ;ds,sd, 128
dw dpbd1 ;ss,dd, 256
dw dpbd2 ;ds,dd, 256
dw dpbd3 ;ss,dd, 512
dw dpbd4 ;ds,dd, 512
dw dpbd5 ;ss,dd, 1024
dw dpbd6 ;ds,dd, 1024
; GAP 3 Length, these values indicate spacing between
; sectors excluding VCO and Sync Field
gpl_tbl db 7 ;SD 128 byte sectors
db 1ah ;DD 256 byte sectors
db 0fh ;DD 512 byte sectors
db 08 ;DD 1024 byte sectors
; FLOPPY MODE BYTE AND TABLE
; B B B B B B B B
; 7 6 5 4 3 2 1 0
; \ / | + ------- set = double density, reset = single density
; | +---------- set = two sided, reset = single sided
; +------------- 0 = 128 byte sectors
; 1 = 256 byte sectors
; 2 = 512 byte sectors
; 3 = 1024 byte sectors
c_fmb db 0 ;the current floppy mode byte
;*******************************************************
;
; Intel 8272 FDC Command Set Data Strctures
;
;*******************************************************
; READ/WRITE DATA Command String
; D C H R N EOT GPL DTL
rw_cmd db 0, 0, 0, 0, 0, 0, 0, 0, 0
; r/w result string
; S S S
; T T T
; 0 1 2 C H R N
rw_res db 0, 0, 0, 0, 0, 0, 0
; READ ID Command String
;
rd_id_cmd db 0, 0
; | +--- head and drive
; +------ control byte
; S S S ;read ID result string
; T T T
; 0 1 2 C H R N
rd_id_res db 0, 0, 0, 0, 0, 0, 0
; RECALIBRATE Command and Result String
;
recal_cmd db F_RECA, 0 ;re-cal command string
; SENSE INTERRUPT STATUS Result String
;
sist_res db 0, 0 ; returned status from an interrupt
; | +--- present cylinder number
; +------ fdc status byte 0
; SPECIFY Command String
;SRT = 3ms, HUT = 240ms
;HLT = 112ms, DMA = on
specify_cmd db F_SPEC, 1101$1111b, 0111000$0b
; SENSE DRIVE STATUS Command/Result Strings
;
sdst_cmd db F_DSTS, 0 ;sense drive status control string
sdst_res db 0 ;sense drive status result byte ST3
; SEEK Command String
;
seek_cmd db F_SEEK, 0, 0
; | +--- new cylinder number
; +------ head and drive
; Retry counter variables
rw_retries db 0
fc_retries db 0 ;first call retries for first recal
;*******************************************************
;
; these are the disk parameters used by the disk routines
;
;*******************************************************
xltbl dw 0 ;translation table address
maxsec dw 0 ;max sectors per track
secsiz dw 0 ;sector size
; floppy disk 0
@dpha dw xltd3
db 0, 0, 0 ;scratch area
db 0 ;door open flag
db 0, 0 ;scratch area
dw dpbd6 ;disk paramater table
dw 0FFFFH, 0FFFFH ;checksum, allocation vector
dw 0FFFFH ;directory bcb
dw 0FFFFH ;data bcb
dw 0FFFFH ;hash table
dw 0 ;init routine
dw fd_login ;login routine
dw fd_read ;read routine
dw 0 ;write routine
db 0 ;unit
db 0 ;channel 0
db 1 ;one flag used
db 0 ;floppy mode byte used by driver
; 1944: 128 Byte Record Capacity
; 243: Kilobyte Drive Capacity
; 64: 32 Byte Directory Entries
; 64: Checked Directory Entries
; 128: 128 Byte Records / Directory Entry
; 8: 128 Byte Records / Block
; 8: 128 Byte Records / Track
; 2: Reserved Tracks
dpbs1: ;single density, single sided.
DW 26 ;sectors per track
DB 3, 7, 0 ;block size=1k, exm=0
DW S1DSM-1, 64-1 ;dsm, drm
DB 0C0h,000h ;2 blocks for directory
DW 8010h ;64/4 cks
DW 2 ;offset by 2 tracks
db 0 ;physical sector shift
db 0 ;physical sector mask
; 3888: 128 Byte Record Capacity
; 486: Kilobyte Drive Capacity
; 128: 32 Byte Directory Entries
; 128: Checked Directory Entries
; 256: 128 Byte Records / Directory Entry
; 16: 128 Byte Records / Block
; 26: 128 Byte Records / Track
; 4: Reserved Tracks
dpbs2: ;single density, double sided.
DW 26 ;sectors per track
DB 4, 15, 1 ;block size=2k, exm=1
DW S2DSM-1, 128-1 ;dsm, drm
DB 0C0h,000h ;2 blocks for directory
DW 8020h ;128/4 cks
DW 2*2 ;offset by 4 tracks
db 0 ;physical sector shift
db 0 ;physical sector mask
; 3888: 128 Byte Record Capacity
; 486: Kilobyte Drive Capacity
; 128: 32 Byte Directory Entries
; 128: Checked Directory Entries
; 128: 128 Byte Records / Directory Entry
; 16: 128 Byte Records / Block
; 52: 128 Byte Records / Track
; 2: Reserved Tracks
dpbd1: ;double density, single sided. (256 byte sectors)
DW 26 ;physical sectors per track
DB 4, 15, 0 ;block size = 2k, exm=0 (should be 1)
DW D1DSM-1, 128-1 ;dsm, drm
DB 0C0h,000h ;2 blocks for directory
DW 8020h ;128/4 cks
DW 2 ;offset 2 tracks
db 1 ;physical sector shift
db 1 ;physical sector mask
; 7792: 128 Byte Record Capacity
; 974: Kilobyte Drive Capacity
; 256: 32 Byte Directory Entries
; 256: Checked Directory Entries
; 128: 128 Byte Records / Directory Entry
; 16: 128 Byte Records / Block
; 52: 128 Byte Records / Track
; 4: Reserved Tracks
dpbd2: ;double density, double sided. (256 byte sectors)
DW 26 ;physical sectors per track
DB 4, 15, 0 ;2k block size, exm=0
DW D2DSM-1, 256-1 ;dsm, drm
DB 0F0h,000h ;4 directory blocks
DW 8040h ;256/4 cks
DW 2*2 ;offset 4 tracks
db 1 ;physical sector shift
db 1 ;physical sector mask
; 4496: 128 Byte Record Capacity
; 562: Kilobyte Drive Capacity
; 128: 32 Byte Directory Entries
; 128: Checked Directory Entries
; 128: 128 Byte Records / Directory Entry
; 16: 128 Byte Records / Block
; 60: 128 Byte Records / Track
; 2: Reserved Tracks
dpbd3: ;double density, single sided. (512 byte sectors)
DW 15 ;physical sectors per track
DB 4, 15, 0 ;2k block size, exm=0
DW D3DSM-1, 128-1 ;dsm, drm
DB 0C0h,000h ;2 directory blocks
DW 8020h ;128/4 cks
DW 2 ;offset 2 tracks
db 2 ;physical sector shift
db 3 ;physical sector mask
; 8992: Byte Record Capacity
; 1124: Kilobyte Drive Capacity
; 256: 32 Byte Directory Entries
; 256: Checked Directory Entries
; 128: 128 Byte Records / Directory Entry
; 16: 128 Byte Records / Block
; 60: 128 Byte Records / Track
; 4: Reserved Tracks
dpbd4: ;double density, double sided. (512-byte sectors)
DW 15 ;physical sectors per track
DB 4, 15, 0 ;2k block size, exm=0
DW D4DSM-1, 256-1 ;dsm, drm
DB 0F0h,000h ;4 directory blocks
DW 8040h ;256/4 cks
DW 2*2 ;offset 4 tracks
db 2 ;physical sector shift
db 3 ;physical sector mask
; 4800: 128 Byte Record Capacity
; 600: Kilobyte Drive Capacity
; 128: 32 Byte Directory Entries
; 128: Checked Directory Entries
; 128: 128 Byte Records / Directory Entry
; 16: 128 Byte Records / Block
; 8: 128 Byte Records / Track
; 2: Reserved Tracks
dpbd5: ;double density, single sided. (1024-byte sectors)
DW 8 ;physical sectors per track
DB 4, 15, 0 ;2k block size, exm=0
DW D5DSM-1, 128-1 ;dsm, drm
DB 0C0h,000h ;2 directory blocks
DW 8020h ;128/4 cks, semi-permanent
DW 2 ;offset 2 tracks
db 3 ;physical sector shift
db 7 ;physical sector mask
; 9600: 128 Byte Record Capacity
; 1200: Kilobyte Drive Capacity
; 256: 32 Byte Directory Entries
; 256: Checked Directory Entries
; 128: 128 Byte Records / Directory Entry
; 16: 128 Byte Records / Block
; 8: 128 Byte Records / Track
; 4: Reserved Tracks
dpbd6: ;double density, double sided. (1024-byte sectors)
DW 8 ;physical sectors per track
DB 4, 15, 0 ;2k block size, exm=0
DW D6DSM-1, 256-1 ;dsm, drm
DB 0F0h,000h ;4 directory blocks
DW 8040h ;256/4 cks, semi-permanent
DW 2*2 ;offset 4 tracks
db 3 ;physical sector shift
db 7 ;physical sector mask
; THESE ARE THE SKEW TABLES
; sector translation tables (for floppy disks)
xtable dw xlts ;single 128
dw xltd1 ;double 256
dw xltd2 ;double 512
dw xltd3 ;double 1024
xlts db 0,6,12,18,24,4,10,16,22,2,8,14,20 ;physical skew = 6
db 1,7,13,19,25,5,11,17,23,3,9,15,21 ;26 sectors/track
;128 byte sectors
xltd1 db 0,9,18,1,10,19,2,11,20,3,12,21 ;physical skew = 9
db 4,13,22,5,14,23,6,15,24,7,16,25 ;26 sectors/track
db 8,17 ;256 byte sectors
xltd2 db 0,4,8,12,1,5,9,13 ;physical skew = 4
db 2,6,10,14,3,7,11 ;15 sectors/track
;512 byte sectors
xltd3 DB 0,3,6,1,4,7,2,5 ;physical skew = 3
;8 sectors per track
;1024 byte sectors
END

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