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[src/trunk]: src/common/lib/libc/arch/arm/string swap r1 & ip
details: https://anonhg.NetBSD.org/src/rev/f4764086c17b
branches: trunk
changeset: 789482:f4764086c17b
user: matt <matt%NetBSD.org@localhost>
date: Tue Aug 20 08:05:49 2013 +0000
description:
swap r1 & ip
use adds, eors, etc.
teq -> cmp
diffstat:
common/lib/libc/arch/arm/string/strrchr_arm.S | 72 ++++++++++++++------------
1 files changed, 39 insertions(+), 33 deletions(-)
diffs (153 lines):
diff -r 42b59cbdcf7c -r f4764086c17b common/lib/libc/arch/arm/string/strrchr_arm.S
--- a/common/lib/libc/arch/arm/string/strrchr_arm.S Tue Aug 20 07:52:31 2013 +0000
+++ b/common/lib/libc/arch/arm/string/strrchr_arm.S Tue Aug 20 08:05:49 2013 +0000
@@ -29,7 +29,7 @@
#include <machine/asm.h>
-RCSID("$NetBSD: strrchr_arm.S,v 1.4 2013/08/11 04:56:32 matt Exp $")
+RCSID("$NetBSD: strrchr_arm.S,v 1.5 2013/08/20 08:05:49 matt Exp $")
#ifdef __ARMEL__
#define BYTE0 0x000000ff
@@ -37,49 +37,52 @@
#define BYTE2 0x00ff0000
#define BYTE3 0xff000000
#define lshi lsl
+#define lshis lsls
#else
#define BYTE0 0xff000000
#define BYTE1 0x00ff0000
#define BYTE2 0x0000ff00
#define BYTE3 0x000000ff
#define lshi lsr
+#define lshis lsrs
#endif
- .text
ENTRY(strrchr)
- teq r1, #0 /* searching for NUL? */
+ ands r2, r1, #0xff /* is the byte value NUL? */
bne 1f /* no, do it the hard way */
push {r0, lr} /* save pointer and return addr */
bl PLT_SYM(strlen) /* get length */
- pop {r1, lr} /* restore pointer and returna addr */
- add r0, r0, r1 /* add pointer to length */
- RET /* return */
+ pop {r1, r2} /* restore pointer / return addr */
+ adds r0, r0, r1 /* add pointer to length */
+ RETr(r2) /* return */
-1: mov ip, r0 /* we use r0 at the return value */
- mov r0, #0 /* return NULL by default */
- and r2, r1, #0xff /* restrict to byte value */
-2: tst ip, #3 /* test for word alignment */
+1: mov r1, r0 /* we use r0 at the return value */
+ movs r0, #0 /* return NULL by default */
+2: tst r1, #3 /* test for word alignment */
beq .Lpre_main_loop /* finally word aligned */
- ldrb r3, [ip], #1 /* load a byte */
+ ldrb r3, [r1], #1 /* load a byte */
cmp r3, r2 /* did it match? */
- subeq r0, ip, #1 /* yes, remember that it did */
- teq r3, #0 /* was it NUL? */
+#ifdef __thumb__
+ it eq
+ subeq r0, r1, #1 /* yes, remember that it did */
+#endif
+ cmp r3, #0 /* was it NUL? */
bne 2b /* no, try next byte */
RET /* return */
.Lpre_main_loop:
push {r4, r5} /* save some registers */
#if defined(_ARM_ARCH_7)
- movw r1, #0xfefe /* magic constant; 254 in each byte */
- movt r1, #0xfefe /* magic constant; 254 in each byte */
+ movw ip, #0xfefe /* magic constant; 254 in each byte */
+ movt ip, #0xfefe /* magic constant; 254 in each byte */
#elif defined(_ARM_ARCH_6)
- mov r1, #0xfe /* put 254 in low byte */
- orr r1, r1, r1, lsl #8 /* move to next byte */
- orr r1, r1, r1, lsl #16 /* move to next halfword */
+ mov ip, #0xfe /* put 254 in low byte */
+ orr ip, ip, ip, lsl #8 /* move to next byte */
+ orr ip, ip, ip, lsl #16 /* move to next halfword */
#endif /* _ARM_ARCH_6 */
orr r2, r2, r2, lsl #8 /* move to next byte */
orr r2, r2, r2, lsl #16 /* move to next halfword */
.Lmain_loop:
- ldr r3, [ip], #4 /* load next word */
+ ldr r3, [r1], #4 /* load next word */
#if defined(_ARM_ARCH_6)
/*
* Add 254 to each byte using the UQADD8 (unsigned saturating add 8)
@@ -87,10 +90,10 @@
* become 255. For NUL, it will be 254. When we complement the
* result, if the result is non-0 then we must have encountered a NUL.
*/
- uqadd8 r4, r3, r1 /* NUL detection happens here */
+ uqadd8 r4, r3, ip /* NUL detection happens here */
usub8 r3, r3, r2 /* bias for char looked for? */
- uqadd8 r5, r3, r1 /* char detection happens here */
- and r3, r4, r5 /* merge results */
+ uqadd8 r5, r3, ip /* char detection happens here */
+ ands r3, r4, r5 /* merge results */
mvns r3, r3 /* is the complement non-0? */
beq .Lmain_loop /* no, then keep going */
@@ -104,7 +107,10 @@
*/
bics r5, r5, r4 /* clear any NUL match bits */
beq .Ldone /* no remaining matches, we're done */
- movs r3, r4, lshi #8 /* shift up a byte */
+ lshis r3, r4, #8 /* shift up a byte */
+#ifdef __thumb__
+ itt ne
+#endif
orrsne r3, r3, r3, lshi #8 /* if non 0, copy up to next byte */
orrsne r3, r3, r3, lshi #8 /* if non 0, copy up to last byte */
bics r5, r5, r3 /* clear match bits */
@@ -117,13 +123,13 @@
* If we have multiple matches, we want to the select the "last" match
* in the word which will be the lowest bit set.
*/
- sub r3, r5, #1 /* subtract 1 */
- and r3, r3, r5 /* and with mask */
- eor r5, r5, r3 /* only have the lowest bit set left */
+ subs r3, r5, #1 /* subtract 1 */
+ ands r3, r3, r5 /* and with mask */
+ eors r5, r5, r3 /* only have the lowest bit set left */
clz r5, r5 /* count how many leading zeros */
- add r0, ip, r5, lsr #3 /* divide that by 8 and add to count */
- sub r0, r0, #4 /* compensate for the post-inc */
- teq r4, #0 /* did we read any NULs? */
+ add r0, r1, r5, lsr #3 /* divide that by 8 and add to count */
+ subs r0, r0, #4 /* compensate for the post-inc */
+ cmp r4, #0 /* did we read any NULs? */
beq .Lmain_loop /* no, get next word */
#else
/*
@@ -134,19 +140,19 @@
tst r3, #BYTE0 /* is byte 0 a NUL? */
beq .Ldone /* yes, then we're done */
tst r4, #BYTE0 /* is byte 0 a match? */
- subeq r0, ip, #4 /* yes, remember its location */
+ subeq r0, r1, #4 /* yes, remember its location */
tst r3, #BYTE1 /* is byte 1 a NUL? */
beq .Ldone /* yes, then we're done */
tst r4, #BYTE1 /* is byte 1 a match? */
- subeq r0, ip, #3 /* yes, remember its location */
+ subeq r0, r1, #3 /* yes, remember its location */
tst r3, #BYTE2 /* is byte 2 a NUL? */
beq .Ldone /* yes, then we're done */
tst r4, #BYTE2 /* is byte 2 a match? */
- subeq r0, ip, #2 /* yes, remember its location */
+ subeq r0, r1, #2 /* yes, remember its location */
tst r3, #BYTE3 /* is byte 3 a NUL? */
beq .Ldone /* yes, then we're done */
tst r4, #BYTE3 /* is byte 3 a match? */
- subeq r0, ip, #1 /* yes, remember its location */
+ subeq r0, r1, #1 /* yes, remember its location */
b .Lmain_loop
#endif /* _ARM_ARCH_6 */
.Ldone:
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