[src/trunk]: src/common/lib/libc/arch/arm/string cbnz/cbz can not branch back...

[matt <matt%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/c5012783cd23
branches:  trunk
changeset: 789462:c5012783cd23
user:      matt <matt%NetBSD.org@localhost>
date:      Mon Aug 19 17:02:25 2013 +0000

description:
cbnz/cbz can not branch backwards so nuke 'em.
Use the same register usage in strlen as in strnlen

diffstat:

 common/lib/libc/arch/arm/string/strcat_naive.S  |  10 +---------
 common/lib/libc/arch/arm/string/strchr_naive.S  |   6 +-----
 common/lib/libc/arch/arm/string/strlen_naive.S  |  12 ++++++------
 common/lib/libc/arch/arm/string/strrchr_naive.S |   6 +-----
 4 files changed, 9 insertions(+), 25 deletions(-)

diffs (120 lines):

diff -r ec59d24b341e -r c5012783cd23 common/lib/libc/arch/arm/string/strcat_naive.S
--- a/common/lib/libc/arch/arm/string/strcat_naive.S    Mon Aug 19 16:34:29 2013 +0000
+++ b/common/lib/libc/arch/arm/string/strcat_naive.S    Mon Aug 19 17:02:25 2013 +0000
@@ -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__ */
diff -r ec59d24b341e -r c5012783cd23 common/lib/libc/arch/arm/string/strchr_naive.S
--- a/common/lib/libc/arch/arm/string/strchr_naive.S    Mon Aug 19 16:34:29 2013 +0000
+++ b/common/lib/libc/arch/arm/string/strchr_naive.S    Mon Aug 19 17:02:25 2013 +0000
@@ -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 @@
        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
diff -r ec59d24b341e -r c5012783cd23 common/lib/libc/arch/arm/string/strlen_naive.S
--- a/common/lib/libc/arch/arm/string/strlen_naive.S    Mon Aug 19 16:34:29 2013 +0000
+++ b/common/lib/libc/arch/arm/string/strlen_naive.S    Mon Aug 19 17:02:25 2013 +0000
@@ -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 @@
 #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 */
diff -r ec59d24b341e -r c5012783cd23 common/lib/libc/arch/arm/string/strrchr_naive.S
--- a/common/lib/libc/arch/arm/string/strrchr_naive.S   Mon Aug 19 16:34:29 2013 +0000
+++ b/common/lib/libc/arch/arm/string/strrchr_naive.S   Mon Aug 19 17:02:25 2013 +0000
@@ -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 @@
        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 */