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;
; Ullrich von Bassewitz, 31.05.1998
; Christian Krueger: 2013-Jul-24, minor optimizations
;
; char* strcat (char* dest, const char* src);
;
.export _strcat
.import popax
.importzp ptr1, ptr2, tmp3
.macpack cpu
_strcat:
sta ptr1 ; Save src
stx ptr1+1
jsr popax ; Get dest
sta tmp3 ; Remember for function return
tay
.if (.cpu .bitand ::CPU_ISET_65SC02)
stz ptr2
.else
lda #0
sta ptr2 ; access from page start, y contains low byte
.endif
stx ptr2+1
findEndOfDest:
lda (ptr2),y
beq endOfDestFound
iny
bne findEndOfDest
inc ptr2+1
bne findEndOfDest
endOfDestFound:
sty ptr2 ; advance pointer to last y position
ldy #0 ; reset new y-offset
copyByte:
lda (ptr1),y
sta (ptr2),y
beq done
iny
bne copyByte
inc ptr1+1
inc ptr2+1
bne copyByte ; like bra here
; return pointer to dest
done: lda tmp3 ; X does still contain high byte
rts
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