strlower.s

;
; Ullrich von Bassewitz, 02.06.1998
;
; char* strlower (char* s);
; char* strlwr (char* s);
;
; Non-ANSI
;

 	.export		_strlower, _strlwr
	.import		popax
	.import		__ctype, __cdiff
	.importzp	ptr1, ptr2

_strlower:
_strlwr:
	sta	ptr1		; Save s (working copy)
	stx	ptr1+1		
	sta	ptr2
	sta	ptr2+2		; save function result
	ldy	#0

loop:	lda    	(ptr1),y	; get character
	beq	L9		; jump if done
	tax
	lda	__ctype,x	; get character classification
	and	#$02		; upper case char?
	beq	L1		; jump if no
	txa			; get character back into accu
	sec
	sbc	__cdiff		; make lower case char
	sta	(ptr1),y	; store back
L1:	iny	    		; next char
	bne	loop
	inc	ptr1+1		; handle offset overflow
	bne	loop		; branch always

; Done, return the argument string

L9:	lda	ptr2
	ldx	ptr2+1
	rts

strlower.s.html; generated on Sat Oct 13 22:41:32 2001 by ca65html
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