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cc65/libsrc/kim1/write.s
Jeff Tranter 806ffe5675 Fixes and improvements to KIM-1 i/o routines.
Tested on real KIM-1 hardware.

read.s:
- Remove commented out line.
- Remove unused check for bell character.
- Remove echo of newline (hardware always echoes entered characters).
- This fixes gets() and fgets() so they return when CR is entered.

write.s:
- Fix check for adding return after linefeed (failed to work because OUTCHR changes A)
- Remove unused check for bell character.

kim1.inc:
- Add symbol for monitor entry

crt0.s:
- Jump to KIM-1 monitor by address rather than using BRK (which relies on vector being set in RAM)
2023-03-27 17:56:25 -04:00

49 lines
1.1 KiB
ArmAsm

;
; int __fastcall__ write (int fd, const void* buf, int count);
;
.include "kim1.inc"
.import popax, popptr1
.importzp ptr1, ptr2, ptr3
.export _write
.proc _write
sta ptr3
stx ptr3+1 ; Count in ptr3
inx
stx ptr2+1 ; Increment and store in ptr2
tax
inx
stx ptr2
jsr popptr1 ; Buffer address in ptr1
jsr popax
begin: dec ptr2
bne outch
dec ptr2+1
beq done
outch: ldy #0
lda (ptr1),y
pha ; Save A (changed by OUTCHR)
jsr OUTCHR ; Send character using Monitor call
pla ; Restore A
cmp #$0A ; Check for '\n'
bne next ; ...if LF character
lda #$0D ; Add a carriage return
jsr OUTCHR
next: inc ptr1
bne begin
inc ptr1+1
jmp begin
done: lda ptr3
ldx ptr3+1
rts ; Return count
.endproc