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Digital-Research-Source-Code/MPM OPERATING SYSTEMS/MPM II/MPM II SOURCE/CONTROL/RESXIOS.ASM
Sepp J Morris 31738079c4 Upload 
Digital Research
2020-11-06 18:50:37 +01:00

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title 'MP/M II V2.0 DSC-2 Basic & Extended I/O Systems'
cseg
maclib diskdef
;
; bios for micro-2 computer
;
;
false equ 0
true equ not false
;
debug equ true
ldcmd equ true
;
MHz4 equ true
if MHz4
dlycnst equ 086h
else
dlycnst equ 054h
endif
;
; org 0000h
;
; jump vector for individual subroutines
; jmp coldstart ;cold start
jmp commonbase
wboot:
jmp warmstart ;warm start
jmp const ;console status
jmp conin ;console character in
jmp conout ;console character out
jmp list ;list character out
jmp rtnempty ;punch not implemented
jmp rtnempty ;reader not implemented
jmp home ;move head to home
jmp seldsk ;select disk
jmp settrk ;set track number
jmp setsec ;set sector number
jmp setdma ;set dma address
jmp read ;read disk
jmp write ;write disk
jmp pollpt ;list status
jmp sectran ;sector translate
jmp selmemory ; select memory
jmp polldevice ; poll device
jmp startclock ; start clock
jmp stopclock ; stop clock
jmp exitregion ; exit region
jmp maxconsole ; maximum console number
jmp systeminit ; system initialization
db 0 ; force use of internal dispatch @ idle
; jmp idle ; idle procedure
;
commonbase:
jmp coldstart
swtuser: jmp $-$
swtsys: jmp $-$
pdisp: jmp $-$
xdos: jmp $-$
sysdat: dw $-$
coldstart:
warmstart:
mvi c,0
jmp xdos ; system reset, terminate process
;
;
;I/O handlers
;
;
; MP/M II V2.0 Console Bios
;
;
nmbcns equ 3 ; number of consoles
poll equ 131 ; XDOS poll function
makeque equ 134 ; XDOS make queue function
readque equ 137 ; XDOS read queue function
writeque equ 139 ; XDOS write queue function
xdelay equ 141 ; XDOS delay function
create equ 144 ; XDOS create process function
pllpt equ 0 ; poll printer
plco0 equ 1 ; poll console out #0
plco2 equ 2 ; poll console out #1
plco3 equ 3 ; poll console out #2 (Port 3)
plci3 equ 4 ; poll console in #2 (Port 3)
if debug
plci0 equ 5 ; poll console in #0
endif
;
const: ; Console Status
call ptbljmp ; compute and jump to hndlr
dw pt0st ; console #0 status routine
dw pt2st ; console #1 (Port 2) status rt
dw pt3st ; console #2 (Port 3) status rt
conin: ; Console Input
call ptbljmp ; compute and jump to hndlr
dw pt0in ; console #0 input
dw pt2in ; console #1 (Port 2) input
dw pt3in ; console #2 (Port 3) input
conout: ; Console Output
call ptbljmp ; compute and jump to hndlr
dw pt0out ; console #0 output
dw pt2out ; console #1 (Port 2) output
dw pt3out ; console #2 (Port 3) output
;
ptbljmp: ; compute and jump to handler
; d = console #
; do not destroy d !
mov a,d
cpi nmbcns
jc tbljmp
pop psw ; throw away table address
rtnempty:
xra a
ret
tbljmp: ; compute and jump to handler
; a = table index
add a ; double table index for adr offst
pop h ; return adr points to jump tbl
mov e,a
mvi d,0
dad d ; add table index * 2 to tbl base
mov e,m ; get handler address
inx h
mov d,m
xchg
pchl ; jump to computed cns handler
;
; ASCII Character Equates
;
uline equ 5fh
rubout equ 7fh
space equ 20h
backsp equ 8h
altrub equ uline
;
; Input / Output Port Address Equates
;
data0 equ 40h
sts0 equ data0+1
cd0 equ sts0
data1 equ 48h
sts1 equ data1+1
cd1 equ sts1
data2 equ 50h
sts2 equ data2+1
cd2 equ sts2
data3 equ 58h
sts3 equ data3+1
cd3 equ sts3
;
; Poll Console #0 Input
;
if debug
polci0:
pt0st:
if ldcmd
lda pt0cntr
ora a
mvi a,0
rnz
endif
in sts0
ani 2
rz
mvi a,0ffh
ret
;
pt0in:
if ldcmd
lxi h,pt0cntr
mov a,m
ora a
jz ldcmd0empty
dcr m
lhld pt0ptr
mov a,m
inx h
shld pt0ptr
ret
pt0cntr:
db ldcmd0empty-pt0ldcmd
pt0ptr:
dw pt0ldcmd
pt0ldcmd:
db 'tod '
ldcmd0empty:
endif
mvi c,poll
mvi e,plci0
call xdos
in data0
ani 7fh
ret
;
else
pt0st:
; return 0ffh if ready,
; 000h if not
lda c0inmsgcnt
ora a
rz
mvi a,0ffh
ret
;
; Console #0 Input
;
c0inpd:
dw c2inpd ; pl
db 0 ; status
db 32 ; priority
dw c0instk+18 ; stkptr
db 'c0in ' ; name
db 0 ; console
db 0ffh ; memseg
ds 36
c0instk:
dw 0c7c7h,0c7c7h,0c7c7h
dw 0c7c7h,0c7c7h,0c7c7h
dw 0c7c7h,0c7c7h,0c7c7h
dw c0inp ; starting address
c0inq:
dw 0 ; ql
db 'c0inque ' ; name
dw 1 ; msglen
dw 4 ; nmbmsgs
ds 8
c0inmsgcnt:
ds 2 ; msgcnt
ds 4 ; buffer
c0inqcb:
dw c0inq ; pointer
dw ch0in ; msgadr
ch0in:
db 0
c0inuqcb:
dw c0inq ; pointer
dw char0in ; msgadr
char0in:
db 0
c0inp:
mvi c,makeque
lxi d,c0inq
call xdos ; make the c0inq
c0inloop:
mvi c,flagwait
mvi e,6
call xdos ; wait for c0 in intr flag
mvi c,writeque
lxi d,c0inqcb
call xdos ; write c0in queue
jmp c0inloop
pt0in:
; return character in reg A
mvi c,readque
lxi d,c0inuqcb
call xdos ; read from c0 in queue
lda char0in ; get character
ani 7fh ; strip parity bit
ret
;
endif
;
; Console #0 Output
;
pt0out:
; Reg C = character to output
in sts0
ani 01h
jnz tx0rdy
push b
mvi c,poll
mvi e,plco0
call xdos ; poll console #0 output
pop b
tx0rdy:
mov a,c
out data0
ret
;
; poll console #0 output
;
polco0:
in sts0
ani 01h
rz
mvi a,0ffh
ret
;
;
; Line Printer Driver: TI 810 Serial Printer
; TTY Model 40
;
initflag:
db 0 ; printer initialization flag
list: ; List Output
pt1out:
; Reg c = Character to print
lda initflag
ora a
jnz pt1xx
mvi a,27h
out 49h ; TTY Model 40 init
sta initflag
pt1xx:
in sts1
ani 01h
jnz tx1rdy
push b
mvi c,poll
mvi e,pllpt
call xdos ; poll printer output
pop b
tx1rdy:
mov a,c ; char to register a
out data1
ret
;
; Poll Printer Output
;
pollpt:
; return 0ffh if ready,
; 000h if not
in sts1
ani 01h
rz
mvi a,0ffh
ret
;
; Poll Console #1 (Port 2) Input
;
pt2st:
; return 0ffh if ready,
; 000h if not
lda c2inmsgcnt
ora a
rz
mvi a,0ffh
ret
;
; Console #1 (Port 2) Input
;
c2inpd:
dw 0 ; pl
db 0 ; status
db 34 ; priority
dw c2instk+18 ; stkptr
db 'c2in ' ; name
db 2 ; console
db 0ffh ; memseg
ds 36
c2instk:
dw 0c7c7h,0c7c7h,0c7c7h
dw 0c7c7h,0c7c7h,0c7c7h
dw 0c7c7h,0c7c7h,0c7c7h
dw c2inp ; starting address
c2inq:
dw 0 ; ql
db 'c2inque ' ; name
dw 1 ; msglen
dw 4 ; nmbmsgs
ds 8
c2inmsgcnt:
ds 2 ; msgcnt
ds 4 ; buffer
c2inqcb:
dw c2inq ; pointer
dw ch2in ; msgadr
ch2in:
db 0
c2inuqcb:
dw c2inq ; pointer
dw char2in ; msgadr
char2in:
db 0
c2inp:
mvi c,makeque
lxi d,c2inq
call xdos ; make the c2inq
c2inloop:
mvi c,flagwait
mvi e,8
call xdos ; wait for c2 in intr flag
mvi c,writeque
lxi d,c2inqcb
call xdos ; write c2in queue
jmp c2inloop
pt2in:
; return character in reg A
mvi c,readque
lxi d,c2inuqcb
call xdos ; read from c2 in queue
lda char2in ; get character
ani 7fh ; strip parity bit
ret
;
; Console #1 (Port 2) Output
;
pt2out:
; Reg C = character to output
in sts2
ani 01h
jnz tx2rdy
push b
mvi c,poll
mvi e,plco2
call xdos ; poll console #1 output
pop b
tx2rdy:
mov a,c
out data2
ret
;
; poll console #1 output
;
polco2:
in sts2
ani 01h
rz
mvi a,0ffh
ret
;
; Poll Console #2 (Port 3) Input
;
polci3:
pt3st: ; return 0ffh if ready,
; 000h if not
in sts3
ani 2
rz
mvi a,0ffh
ret
;
; Console #2 (Port 3) Input
;
pt3in: ; return character in reg A
mvi c,poll
mvi e,plci3
call xdos ; poll console #0 input
in data3 ; read character
ani 7fh ; strip parity bit
ret
;
; Console #2 (Port 3) Output
;
pt3out: ; Reg C = character to output
in sts3
ani 01h
jnz tx3rdy
push b
mvi c,poll
mvi e,plco3
call xdos ; poll console #2 (Port 3) output
pop b
tx3rdy:
mov a,c
out data3 ; transmit character
ret
;
; Poll Console #2 (Port 3) Output
;
polco3:
; return 0ffh if ready,
; 000h if not
in sts3
ani 01h
rz
mvi a,0ffh
ret
;
;
; MP/M II V2.0 Xios
;
;
polldevice:
; Reg C = device # to be polled
; return 0ffh if ready,
; 000h if not
mov a,c
cpi nmbdev
jc devok
mvi a,nmbdev; if dev # >= nmbdev,
; set to nmbdev
devok:
call tbljmp ; jump to dev poll code
devtbl:
dw pollpt ; poll printer output
dw polco0 ; poll console #0 output
dw polco2 ; poll console #1 output
dw polco3 ; poll console #2 output
dw polci3 ; poll console #2 input
if debug
dw polci0 ; poll console #0 input
endif
nmbdev equ ($-devtbl)/2 ; number of devices to poll
dw rtnempty; bad device handler
;
; Select / Protect Memory
;
selmemory:
; Reg BC = adr of mem descriptor
; BC -> base 1 byte,
; size 1 byte,
; attrib 1 byte,
; bank 1 byte.
; this hardware does not have memory protection or
; bank switching
ret
;
; Start Clock
;
startclock:
; will cause flag #1 to be set
; at each system time unit tick
mvi a,0ffh
sta tickn
ret
;
; Stop Clock
;
stopclock:
; will stop flag #1 setting at
; system time unit tick
xra a
sta tickn
ret
;
; Exit Region
;
exitregion:
; EI if not preempted or in dispatcher
lda preemp
ora a
rnz
ei
ret
;
; Maximum Console Number
;
maxconsole:
mvi a,nmbcns
ret
;
; System Initialization
;
systeminit:
;
; This is the place to insert code to initialize
; the time of day clock, if it is desired on each
; booting of the system.
;
mvi a,0c3h
sta 0038h
lxi h,inthnd
shld 0039h ; JMP INTHND at 0038H
mvi c,create
if debug
lxi d,c2inpd
else
lxi d,c0inpd
endif
call xdos
lda intmsk
out 60h ; init interrupt mask
db 0edh,056h ; Interrupt Mode 1
; ** Z80 Instruction **
ei
call home
mvi c,flagwait
mvi e,5
jmp xdos ; clear first disk interrupt
; ret ; & return
;
; Idle procedure
;
;idle:
; ret
; -or-
; ei
; hlt
; ret ; for full interrupt system
;
; MP/M II V2.0 Interrupt Handlers
;
flagwait equ 132
flagset equ 133
dsptch equ 142
inthnd:
; Interrupt handler entry point
; All interrupts gen a RST 7
; Location 0038H contains a jmp
; to INTHND.
shld svdhl
pop h
shld svdret
push psw
lxi h,0
dad sp
shld svdsp ; save users stk ptr
lxi sp,lstintstk ; lcl stk for intr hndl
push d
push b
mvi a,0ffh
sta preemp ; set preempted flag
in 60h ; read interrupt mask
ani 01000000b ; test & jump if clk int
jnz clk60hz
;
in stat ; read disk status port
ani 08h
jnz diskintr
if not debug
in sts0
ani 2
jnz con0in
endif
in sts2
ani 2
jnz con2in
; ... ; test/handle other ints
;
jmp intdone
diskintr:
xra a
out cmd1 ; reset disk interrupt
mvi e,5
jmp concmn ; set flag #5
if not debug
con0in:
in data0
sta ch0in
mvi e,6
jmp concmn ; set flag #6
endif
con2in:
in data2
sta ch2in
mvi e,8
; jmp concmn ; set flag #8
concmn:
mvi c,flagset
call xdos
jmp intdone
clk60hz:
; 60 Hz clock interrupt
lda tickn
ora a ; test tickn, indicates
; delayed process(es)
jz notickn
mvi c,flagset
mvi e,1
call xdos ; set flag #1 each tick
notickn:
lxi h,cnt60
dcr m ; dec 60 tick cntr
jnz not1sec
mvi m,60
mvi c,flagset
mvi e,2
call xdos ; set flag #2 @ 1 sec
not1sec:
xra a
out 60h
lda intmsk
out 60h ; ack clock interrupt
; jmp intdone
;
; ...
; Other interrupt handlers
; ...
;
intdone:
xra a
sta preemp ; clear preempted flag
pop b
pop d
lhld svdsp
sphl ; restore stk ptr
pop psw
lhld svdret
push h
lhld svdhl
; The following dispatch call will force round robin
; scheduling of processes executing at the same priority
; each 1/60th of a second.
; Note: Interrupts are not enabled until the dispatcher
; resumes the next process. This prevents interrupt
; over-run of the stacks when stuck or high frequency
; interrupts are encountered.
jmp pdisp ; MP/M dispatch
;
;
; Disk I/O Drivers
;
; Disk Port Equates
;
cmd1 equ 80h
stat equ 80h
haddr equ 81h
laddr equ 82h
cmd2 equ 83h
;
;
home: ;move to the track o0 position of current drive
call headload
; h,l point to word with track for selected disk
homel:
mvi m,00 ;set current track ptr back to 0
in stat ;read fdc status
ani 4 ;test track 0 bit
rz ;return if at 0
stc ;direction=out
call step ;step one track
jmp homel ;loop
;
seldsk:
;drive number in c
lxi h,0 ;0000 in hl produces select error
mov a,c ;a is disk number 0 ... ndisks-1
cpi ndisks ;less than ndisks?
rnc ;return with HL = 0000 if not
;make sure dummy is 0 (for use in double add to h,l)
xra a
sta dummy
mov a,c
ani 07h ;get only disk select bits
sta diskno
mov c,a
;set up the second command port
lda port
ani 0f0h ;clear out old disk select bits
ora c ;put in new disk select bits
ori 08h ; force double density
sta port
; proper disk number, return dpb element address
mov l,c
dad h ;*2
dad h ;*4
dad h ;*8
dad h ;*16
lxi d,dpbase
dad d ;HL=.dpb
shld tran ;translate table base
ret
;
;
;
settrk: ;set track given by register c
call headload
;h,l reference correct track indicator according to
;selected disk
mov a,c ;desired track
cmp m
rz ;we are already on the track
settkx:
call step ;step track-carry has direction
;step will update trk indicator
mov a,c
cmp m ;are we where we want to be
jnz settkx ;not yet
;have stepped enough
seekrt:
;need 10 msec delay for final step time and head settle time
mvi a,20d
; call delay
; ret ;end of settrk routine
;
delay: ;delay for c[A] X .5 milliseconds
push b
delay1:
mvi c,dlycnst ;constant adjusted to .5 ms loop
delay2:
dcr c
jnz delay2
dcr a
jnz delay1
pop b
ret ;end of delay routine
;
setsec: ;set sector given by register c
inr c
mov a,c
sta sector
ret
;
sectran:
;sector number in c
;translate logical to physical sector
lhld tran ;hl=..translate
mov e,m ;E=low(.translate)
inx h
mov d,m ;DE=.translate
mov a,e ;zero?
ora d ;00 or 00 = 00
mvi h,0
mov l,c ;HL = untranslated sector
rz ;skip if so
xchg
mov b,d ;BC=00ss
dad b ;HL=.translate(sector)
mov l,m
mov h,d ;HL=translate(sector)
ret
;
setdma: ;set dma address given by registers b and c
mov l,c ;low order address
mov h,b ;high order address
shld dmaad ;save the address
ret
;
;
read: ;perform read operation.
;this is similar to write, so set up read
; command and use common code in write
mvi b,040h ;set read flag
jmp waitio ;to perform the actual I/O
;
write: ;perform a write operation
mvi b,080h ;set write command
;
waitio:
;enter here from read and write to perform the actual
; I/O operation. return a 00h in register a if the
; operation completes properly, and 01h if an error
; occurs during the read or write
;
;in this case, the disk number saved in 'diskno'
; the track number in 'track'
; the sector number in 'sector'
; the dma address in 'dmaad'
;b still has r/w flag
mvi a,10d ;set error count
sta errors ;retry some failures 10 times
;before giving up
tryagn:
push b
call headload
;h,l point to track byte for selected disk
pop b
mov c,m
; decide whether to allow disk write precompenstation
mvi a,39d ;inhibit precomp on trks 0-39
cmp c
jc allowit
;inhibit precomp
mvi a,10h
ora b
mov b,a ;goes out on the same port
; as read/write
allowit:
lhld dmaad ;get buffer address
push b ;b has r/w code c has track
dcx h ;save and replace 3 bytes below
;buf with trk,sctr,adr mark
mov e,m
;figure correct address mark
lda port
ani 08h
mvi a,0fbh
jz sin
ani 0fh ;was double
;0bh is double density
;0fbh is single density
sin:
mov m,a
;fill in sector
dcx h
mov d,m
lda sector ;note that invalid sector number
;will result in head unloaded
;error, so dont check
mov m,a
;fill in track
dcx h
pop b
mov a,c
mov c,m
mov m,a
mov a,h ;set up fdc dma address
out haddr ;high byte
mov a,l
out laddr ;low byte
mov a,b ;get r/w flag
out cmd1 ;start disk read/write
rwwait:
push b
push d
push h
mvi c,flagwait
mvi e,5
call xdos ; wait for disk intrpt flag
pop h
pop d
pop b
mov m,c ;restore 3 bytes below buf
inx h
mov m,d
inx h
mov m,e
in stat ;test for errors
ani 0f0h
rz ;a will be 0 if no errors
; error from disk
push psw ;save error condition
;check for 10 errors
lxi h,errors
dcr m
jnz redo ;not ten yet. do a retry
;we have too many errors. print out hex number for last
;received error type. cpm will print perm error message.
pop psw ;get code
;set error return for operating system
mvi a,1
ret
redo:
;b still has read/write flag
pop psw ;get error code
ani 0e0h ;retry if not track error
jnz tryagn ;
;was a track error so need to reseek
push b ;save read/write indicator
;figure out the desired track
lxi d,track
lhld diskno ;selected disk
dad d ;point to correct trk indicator
mov a,m ;desired track
push psw ;save it
call home
pop psw
mov c,a
call settrk
pop b ;get read/write indicator
jmp tryagn
;
;
;
step: ;step head out towards zero
;if carry is set; else
;step in
; h,l point to correct track indicator word
jc outx
inr m ;increment current track byte
mvi a,04h ;set direction = in
dostep:
ori 2
out cmd1 ;pulse step bit
ani 0fdh
out cmd1 ;turn off pulse
;the fdc-2 had a stepp ready line. the fdc-3 relies on
;software time out
mvi a,16d ;delay 8 ms
jmp delay
; ret
;
outx:
dcr m ;update track byte
xra a
jmp dostep
;
headload:
;select and load the head on the correct drive
lxi h,prtout ;old slect info
mov b,m
dcx h ;new select info
mov a,m
inx h
mov m,a
ori 10h ; enable interrupt
out cmd2 ;select the drive
ani 0efh
;set up h.l to point to track byte for selected disk
lxi d,track
lhld diskno
dad d
;now check for needing a 35 ms delay
;if we have changed drives or if the head is unloaded
;we need to wait 35 ms for head settle
cmp b ;are we on the same drive
jnz needdly
;we are on the same drive
;is the head loaded?
in stat
ani 80h
rz ;already loaded
needdly:
xra a
out cmd1 ;load the head
mvi a,70d
jmp delay
; ret
;
; BIOS Data Segment
;
cnt60: db 60 ; 60 tick cntr = 1 sec
intstk: ; local intrpt stk
dw 0c7c7h,0c7c7h,0c7c7h,0c7c7h,0c7c7h
dw 0c7c7h,0c7c7h,0c7c7h,0c7c7h,0c7c7h
dw 0c7c7h,0c7c7h,0c7c7h,0c7c7h,0c7c7h
dw 0c7c7h,0c7c7h,0c7c7h,0c7c7h,0c7c7h
lstintstk:
svdhl: dw 0 ; saved Regs HL during int hndl
svdsp: dw 0 ; saved SP during int hndl
svdret: dw 0 ; saved return during int hndl
tickn: db 0 ; ticking boolean,true = delayed
if debug
intmsk: db 44h ; intrpt msk, enables clk intrpt, & con2
else
intmsk: db 54h ; intrpt msk, enables clk intrpt, & con0/2
endif
preemp: db 0 ; preempted boolean
;
scrat: ; start of scratch area
track: db 0 ; current trk on drive 0
trak1: db 0 ; current trk on drive 1
trak2: db 0
trak3: db 0
sector: db 0 ; currently selected sctr
dmaad: dw 0 ; current dma address
diskno: db 0 ; current disk number
dummy: db 0 ; must be 0 for dbl add
errors: db 0
port: db 0
prtout: db 0
dnsty: db 0
;
disks 2
bpb equ 2*1024 ;bytes per block
rpb equ bpb/128 ;records per block
maxb equ 255 ;max block number
diskdef 0,1,58,,bpb,maxb+1,128,128,2,0
diskdef 1,0
;
tran: ds 2
;
endef
db 0 ;force out last byte in hex file
end

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