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Fix bug in return value of strcmp/strncmp #12

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merged 2 commits into from
Mar 20, 2024
Merged

Fix bug in return value of strcmp/strncmp #12

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26d6dd6
Fix return value of strcmp and strncmp, optimize strncmp loop
calc84maniac Mar 20, 2024
2bd3c8a
Improve some ZDS pseudo op replacements
calc84maniac Mar 20, 2024
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3 changes: 1 addition & 2 deletions lib/libc/setjmp.src
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Original file line number Diff line number Diff line change
Expand Up @@ -34,8 +34,7 @@
_setjmp:
ld iy,0
add iy,sp
push iy ; replacing ld hl,iy ZDS pseudo op
pop hl
lea hl,iy ; replacing ld hl,iy ZDS pseudo op
ld iy,(iy+3) ;get jmp_buf
ld (iy+3),ix ;save ix
ld (iy+6),hl ;save sp
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15 changes: 7 additions & 8 deletions lib/libc/strcmp.src
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Original file line number Diff line number Diff line change
@@ -1,5 +1,7 @@
; (c) Copyright 2007-2008 Zilog, Inc.
; int strcmp(register char *s1, register char *s2)
; Changed to remove bug of typecasting difference value to signed char - should be difference of unsigned chars
; Brendan Fletcher 19/03/2024

assume ADL=1

Expand All @@ -14,22 +16,19 @@ _strcmp:
inc hl
ld hl, (hl)

_loop:
.loop:
ld a, (de)
or a, a
jr z, _done
jr z, .done
cpi
inc de
jr z, _loop
jr z, .loop

dec hl
_done:
.done:
sub a, (hl)

ld b, a
rla
sbc hl, hl
ld l, b
ld l, a
ret


63 changes: 29 additions & 34 deletions lib/libc/strncmp.src
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Original file line number Diff line number Diff line change
@@ -1,44 +1,39 @@
; (c) Copyright 2007-2008 Zilog, Inc.
; int strncmp(char *s1,char *s2,size_t n)
; Changed to remove bug of typecasting difference value to signed char - should be difference of unsigned chars
; Brendan Fletcher 19/03/2024

ASSUME ADL=1

section .text
public _strncmp
_strncmp:
ld iy, 0
add iy, sp

ld bc, (iy+9)
ld a, (iy+11)
or a, c
or a, b
jr z, _done ; n==0 ? return(0)

ld hl, (iy+6)
ld de, (iy+3)

_cloop:
ld a, (de)
ld iy, 0
add iy, sp

ld bc, (iy+9)
ld a, (iy+11)
or a, c
or a, b
jr z, .done ; n==0 ? return(0)

ld hl, (iy+6)
ld de, (iy+3)

.cloop:
ld a, (de)
or a, a
jr z, .diffnul ; return the difference value if *s1=='\0'
cpi
jr nz, _diff ; return the difference value if mismatch occurs
jp po, _done ; if all the chars over then return(0)
or a, a
jr z, _done ; if *s1=='\0' return(0)
inc de
jr _cloop

_diff:
dec hl
sub a, (hl)
ld b, a
rla
sbc hl, hl
ld l, b
jr nz, .diff ; return the difference value if mismatch occurs
inc de
jp pe, .cloop ; if all the chars not over then loop

.diff:
dec hl
.diffnul:
sub a, (hl)
.done:
sbc hl, hl
ld l, a
ret

_done:
or a, a
sbc hl, hl
ret

11 changes: 5 additions & 6 deletions lib/libc/strstr.src
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Original file line number Diff line number Diff line change
Expand Up @@ -10,7 +10,7 @@
public _strstr
_strstr:
ld hl, 6
add hl, sp
add hl, sp
ld iy, (hl) ; bc = s2
dec hl
dec hl
Expand All @@ -22,21 +22,20 @@ _L0:
add hl,de
cp a,(hl)
jr z,_L3 ; *s1 == '\0'
push iy ; replace ZDS pseudo op ld bc,iy
pop bc
lea bc,iy ; replace ZDS pseudo op ld bc,iy
inc de
_L1:
ld a,(bc)
or a,a
jr z,_L2 ; *s2 == '\0'
cp a,(hl) ; *s1 == *s2
inc hl ; s1 ++
inc bc ; s2 ++
inc hl ; s1 ++
inc bc ; s2 ++
jr z,_L1
jr _L0
_L2:
ex de,hl
dec hl
dec hl
ret
_L3:
sbc hl,hl
Expand Down