ack/mach/z80/libmon/mon.s

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1985-04-01 14:44:26 +00:00
.define .mon
1987-02-02 12:44:39 +00:00
.sect .text
.sect .rom
.sect .data
.sect .bss
.sect .text
1985-04-01 14:44:26 +00:00
! Monitor call
! Expects on stack: monitor call number
! parameters
! Implemented are the following monitor calls:
! number 1: exit
! number 3: read
! number 4: write
! number 5: open
! number 6: close
! number 54: ioctl
! If called with a number of a call that is not implemented,
! a trap is generated.
.mon:
pop ix ! returnaddress
pop hl ! monitor call number
ld a,l
cp 1
jp z,monexit ! is it an exit?
cp 3
jp z,monread ! is it a read?
cp 4
jp z,monwrite ! is it a write?
cp 5
jp z,monopen ! is it an open?
cp 6
jp z,monclose ! is it a close?
cp 54
jp z,monioctl
jp ebadmon ! trap
monexit:
jp 0x38
monread:
pop hl ! file-descriptor, not used
pop hl ! hl = pointer to output buffer
pop de ! de = number of bytes to be read
ld bc,0 ! bc will contain the number of bytes actually read
1: ld a,d
or e
jr z,2f
call getchar
push af
call putchar ! echo character
pop af
ld (hl),a
inc hl
inc bc
dec de
cp 0x0A ! is it a newline?
jp nz,1b
2: push bc
ld hl,0
push hl
jp (ix)
monwrite:
pop hl ! file-descriptor, not used
pop hl ! hl = pointer to output buffer
pop de ! de = number of bytes
push de
1: ld a,e
or d
jr z,2f
ld a,(hl)
call putchar
inc hl
dec de
jp 1b
2: push de ! no error
jp (ix)
monopen:
pop hl ! pointer to string
pop hl ! flag
ld hl,-1
push hl ! push file descriptor
push hl ! push error code twice
push hl
jp (ix)
monclose:
ex (sp),hl ! pop file descriptor and push error code
pop hl ! file descriptor
ld hl,-1
push hl ! push error code twice
push hl
jp (ix)
monioctl:
pop hl ! file descriptor
pop hl ! request
ld hl,0
ex (sp),hl ! remove argp and push error code
jp (ix)