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cbnz/cbz can not branch backwards so nuke 'em.

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Use the same register usage in strlen as in strnlen
This commit is contained in:
matt 2013-08-19 17:02:25 +00:00
parent 3c46e5578f
commit ddea6e9586
4 changed files with 9 additions and 25 deletions
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10
common/lib/libc/arch/arm/string/strcat_naive.S
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@ -29,30 +29,22 @@
#include <machine/asm.h>
RCSID("$NetBSD: strcat_naive.S,v 1.2 2013/08/19 02:54:02 matt Exp $")
RCSID("$NetBSD: strcat_naive.S,v 1.3 2013/08/19 17:02:25 matt Exp $")
ENTRY(strcat)
mov ip, r0 /* need to preserve r0 */
#if defined(__thumb__)
1: ldrb r2, [r0] /* load next byte */
adds r0, r0, #1 /* advance */
#if defined(_ARM_ARCH_T2)
cbnz r2, 1b /* was it a NUL? no, get next byte */
#else
cmp r2, #0 /* was it a NUL? */
bne 1b /* no, get next byte */
#endif
subs r0, r0, #1 /* back up one to the NUL */
subs r1, r1, r0 /* save one increment */
2: ldrb r2, [r1, r0] /* load next byte from append */
strb r2, [r0] /* store it */
adds r0, r0, #1 /* advance */
#if defined(_ARM_ARCH_T2)
cbnz r2, 1b /* was it a NUL? no, get next byte */
#else
cmp r2, #0 /* was it a NUL? */
bne 2b /* no, get next byte */
#endif
mov r0, ip /* restore dst address */
RET /* return */
#else /* !__thumb__ */

6
common/lib/libc/arch/arm/string/strchr_naive.S
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@ -28,7 +28,7 @@
*/
#include <machine/asm.h>
RCSID("$NetBSD: strchr_naive.S,v 1.3 2013/08/19 02:22:25 matt Exp $")
RCSID("$NetBSD: strchr_naive.S,v 1.4 2013/08/19 17:02:25 matt Exp $")
/* LINTSTUB: char * strchr(const char *, int) */
ENTRY(strchr)
@ -39,12 +39,8 @@ ENTRY(strchr)
cmp r3, r1 /* does it match? */
beq 2f /* yes, set return value */
adds r0, r0, #1 /* advance to next byte */
#ifdef _ARM_ARCH_T2
cbnz r3, 1b /* was it a NUL? no, get next byte */
#else
cmp r3, #0 /* was it a NUL? */
bne 1b /* no, get next byte */
#endif
movs r0, #0 /* set return to NULL */
2: RET /* return */
#else

12
common/lib/libc/arch/arm/string/strlen_naive.S
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@ -28,7 +28,7 @@
*/
#include <machine/asm.h>
RCSID("$NetBSD: strlen_naive.S,v 1.7 2013/08/19 02:13:13 matt Exp $")
RCSID("$NetBSD: strlen_naive.S,v 1.8 2013/08/19 17:02:25 matt Exp $")
#ifdef STRNLEN
/* LINTSTUB: size_t strnlen(const char *, size_t) */
@ -58,17 +58,17 @@ END(strnlen)
#else /* STRNLEN */
/* LINTSTUB: size_t strlen(const char *) */
ENTRY(strlen)
adds r2, r0, #1 /* start of src + NUL */
adds r3, r0, #1 /* start of src + NUL */
1:
#ifdef __thumb__
ldrb r3, [r0] /* read a byte */
ldrb r2, [r0] /* read a byte */
adds r0, r0, #1
#else
ldrb r3, [r0], #1 /* read a byte */
ldrb r2, [r0], #1 /* read a byte */
#endif
cmp r3, #0 /* is it a NUL? */
cmp r2, #0 /* is it a NUL? */
bne 1b /* no, get next byte */
subs r0, r0, r2 /* return difference between start and end */
subs r0, r0, r3 /* return difference between start and end */
RET
END(strlen)
#endif /* !STRNLEN */

6
common/lib/libc/arch/arm/string/strrchr_naive.S
View File

@ -28,7 +28,7 @@
*/
#include <machine/asm.h>
RCSID("$NetBSD: strrchr_naive.S,v 1.3 2013/08/19 02:36:27 matt Exp $")
RCSID("$NetBSD: strrchr_naive.S,v 1.4 2013/08/19 17:02:25 matt Exp $")
/* LINTSTUB: char * strrchr(const char *, int) */
ENTRY(strrchr)
@ -42,12 +42,8 @@ ENTRY(strrchr)
bne 2f /* no, go and advance */
mov r0, r2 /* yes, set return value to point to it */
2: adds r2, r2, #1 /* advance to next byte */
#ifdef _ARM_ARCH_T2
cbnz r3, 1b /* was it a NUL? no, get next byte */
#else
cmp r3, #0 /* was it a NUL? */
bne 1b /* no, get next byte */
#endif
#else
and r1, r1, #0xff /* restrict to a byte value */
1: ldrb r3, [r2], #1 /* read a byte */