202 lines
2.9 KiB
ArmAsm
202 lines
2.9 KiB
ArmAsm
.define _read,_write,_ioctl,_getpid,_open,_close,_exit,_errno
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.sect .text
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.sect .rom
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.sect .data
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.sect .bss
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.sect .text
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_read:
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ld (savebc),bc
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push af
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pop bc
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ld (saveaf),bc ! save all registers in savereg
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ld (savede),de
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ld (savehl),hl
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ld (saveix),ix
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ex (sp),hl ! return address in hl
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pop bc ! skip return address
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pop bc ! get fd
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ld a,b ! check fd = 0
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or c
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jr nz,errrd
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pop de ! get buffer
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pop bc ! get count
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ld ix,0 ! reset counter
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push bc
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push de
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push ix
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push hl ! return address
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ex de,hl ! buffer to hl
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1: ld a,b
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or c
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jr z,done ! done if count = 0
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call getchr
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ld (hl),a
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inc hl ! increment pointer
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inc ix ! increment char counter
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dec bc ! decrement count
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cp 0xA
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jr nz,1b ! done if char = CR
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done:
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ld bc,(saveaf)
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push bc
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pop af
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ld bc,(savebc)
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ld de,(savede)
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ld hl,(savehl)
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ld ix,(saveix)
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ret
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errrd:
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push bc
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push hl ! return address
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ld bc,(saveaf)
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push bc
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pop af
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ld bc,(savebc)
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ld de,(savede)
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ld hl,(savehl)
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ld ix,(saveix)
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ld ix,-1
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ret
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_write:
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ld (savebc),bc
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push af
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pop bc
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ld (saveaf),bc ! save all registers in savereg
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ld (savede),de
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ld (savehl),hl
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ld (saveix),ix
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ex (sp),hl ! return address in hl
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pop de ! skip return address
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pop de ! get fd
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ld a,e ! check for fd = 1
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cp 1
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jr nz,errwr
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ld a,d
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or a
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jr nz,errwr
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pop de ! buffer in de
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pop bc ! count in bc
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push bc
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push de
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push de
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push hl
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ex de,hl ! buffer in hl
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ld e,c
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ld d,b ! count also in de
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1: ld a,b
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or c
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jr z,exit
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ld a,(hl)
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call putchr
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inc hl
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dec bc
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jr 1b
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errwr:
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push de
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push hl
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ld bc,(saveaf)
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push bc
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pop af
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ld bc,(savebc)
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ld de,(savede)
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ld hl,(savehl)
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ld ix,(saveix)
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ld ix,-1 ! error in fd
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ret
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exit:
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push de ! count on stack
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ld bc,(saveaf)
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push bc
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pop af
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ld bc,(savebc)
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ld de,(savede)
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ld hl,(savehl)
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ld ix,(saveix)
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pop ix ! return count to caller
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ret
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_ioctl:
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ret
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_getpid:
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ret
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! open return a file descriptor (0,1,2)
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! depending on 'mode'
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! mode 2 doesn't work!!
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_open:
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ld (savebc),bc
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push af
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pop bc
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ld (saveaf),bc ! save all registers in savereg
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ld (savede),de
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ld (savehl),hl
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ld (saveix),ix
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pop bc ! return address
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pop de ! name pointer
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pop ix ! mode (0 for read,
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! 1 for write)
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push ix
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push de
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push bc
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ld bc,(saveaf)
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push bc
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pop af
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ld bc,(savebc)
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ld de,(savede)
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ld hl,(savehl)
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ld ix,(saveix)
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ret ! return fd = 0 for read
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! fd = 1 for write
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_close:
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ld ix,0 ! return succes
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ret
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_exit:
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jp 0x38
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.sect .data
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_errno:
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.data2 0
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! output routine in monitor
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CRT = 0x013B
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! output a charcter
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! entry: ascii character in a
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.sect .text
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!putchr:
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! push hl
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! push bc
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! ld hl,tab
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! ld b,5
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!1: cp (hl)
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! jr z,fetch
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! inc hl
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! inc hl
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! djnz 1b
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!2: call CRT
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! pop bc
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! pop hl
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! ret
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!fetch: inc hl
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! ld a,(hl)
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! jr 2b
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!! conversion table for nascom characters
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!tab: .data1 0x0D,0x00
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! .data1 0x1B,0x1E
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! .data1 0x08,0x1D
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! .data1 0x0A,0x1F
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! .data1 0x7F,0x00
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KBD = 0x69
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! get character from keyboard
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getchr:
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call KBD
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jr nc,getchr
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cp 0x1F
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jr z,CR
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cp 0x1D
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jr z,BS
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ret
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CR: ld a,0xA
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ret
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BS: ld a,0x8
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ret
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