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cc65/libsrc/common/fputc.s
2024-01-30 19:40:28 +01:00

67 lines
1.3 KiB
ArmAsm

;
; Colin Leroy-Mira, 2024
;
; int __fastcall__ fputc (int c, FILE* f);
;
.export _fputc
.importzp ptr1
.import _write, checkferror
.import pushax, pusha0, popax, incsp2
.import pushptr1, popptr1, returnFFFF
.include "stdio.inc"
.include "_file.inc"
_fputc:
sta ptr1
stx ptr1+1
jsr popax ; Get char, as we'll have
sta c ; to return it anyway
stx c+1
jsr checkferror
bne ret_eof
jsr pushptr1 ; Backup fp pointer
; Push _write parameters
ldy #_FILE::f_fd
lda (ptr1),y
jsr pusha0
lda #<c
ldx #>c
jsr pushax
lda #$01
ldx #$00
; Write
jsr _write
; Check for errors
cmp #$01
bne set_ferror
; Return char
lda c
ldx #$00
jmp incsp2 ; Drop fp pointer copy
ret_eof:
jmp returnFFFF
set_ferror:
jsr popptr1
lda #_FERROR
ldy #_FILE::f_flags
ora (ptr1),y
sta (ptr1),y
jmp returnFFFF
.bss
c: .res 2