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