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cc65/libsrc/common/gets.s
Colin Leroy-Mira aa6f850b8d Rewrite gets in assembler
+19 bytes if used alone, because it pulls in fgets, but as code is
factorized, -128 bytes in programs using both fgets and gets.
2024-01-26 20:29:17 +01:00

48 lines
1.0 KiB
ArmAsm

;
; Colin Leroy-Mira, 2024
;
; char* __fastcall__ gets (char* s)
;
.export _gets
.import _fgets, _stdin, popax, pushax
.importzp ptr4
_gets:
; Push buffer
sta ptr4
stx ptr4+1
jsr pushax
; Push size (there's no limit!)
lda #$FF
tax
jsr pushax
lda _stdin
ldx _stdin+1
jsr _fgets
; Check return value
bne :+
cpx #$00
bne :+
rts
: ; At least one byte written.
jsr pushax ; Store returned pointer
; Remove \n if there is one.
lda ptr4 ; _fgets returns with ptr4 at
bne :+ ; end of buffer
dec ptr4+1
: dec ptr4
lda (ptr4),y ; _fgets returns with Y=0
cmp #$0A
bne :+
tya
sta (ptr4),y ; Set terminator over \n
: jmp popax