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Added "strrchr" optimizaion a matching unit test and tiny unit test framework. (Documentation for that will follow later)

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IrgendwerA8
2017-02-26 20:03:05 +01:00
parent 6afcc370ed
commit c240d42a9e
4 changed files with 167 additions and 83 deletions
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58
libsrc/common/strrchr.s
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@@ -1,47 +1,41 @@
;
; Ullrich von Bassewitz, 31.05.1998
; Christian Krueger: 2013-Aug-01, optimization
;
; char* strrchr (const char* s, int c);
;
.export _strrchr
.import popax
.importzp ptr1, ptr2, tmp1
.importzp ptr1, tmp1, tmp2
_strrchr:
sta tmp1 ; Save c
jsr popax ; get s
sta ptr1
stx ptr1+1
lda #0 ; function result = NULL
sta ptr2
sta ptr2+1
tay
sta tmp1 ; Save c
jsr popax ; get s
tay ; low byte to y
stx ptr1+1
ldx #0 ; default function result is NULL, X is high byte...
stx tmp2 ; tmp2 is low-byte
stx ptr1 ; low-byte of source string is in Y, so clear real one...
testChar:
lda (ptr1),y ; get char
beq finished ; jump if end of string
cmp tmp1 ; found?
bne nextChar ; jump if no
L1: lda (ptr1),y ; get next char
beq L3 ; jump if end of string
cmp tmp1 ; found?
bne L2 ; jump if no
charFound:
sty tmp2 ; y has low byte of location, save it
ldx ptr1+1 ; x holds high-byte of result
; Remember a pointer to the character
nextChar:
iny
bne testChar
inc ptr1+1
bne testChar ; here like bra...
tya
clc
adc ptr1
sta ptr2
lda ptr1+1
adc #$00
sta ptr2+1
; return the pointer to the last occurrence
; Next char
L2: iny
bne L1
inc ptr1+1
bne L1 ; jump always
; Return the pointer to the last occurrence
L3: lda ptr2
ldx ptr2+1
finished:
lda tmp2 ; high byte in X is already correct...
rts