[src/trunk]: src/common/lib/libc/arch/arm/string thumbify (part2)

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

details:   https://anonhg.NetBSD.org/src/rev/6c89ef997e6c
branches:  trunk
changeset: 789483:6c89ef997e6c
user:      matt <matt%NetBSD.org@localhost>
date:      Tue Aug 20 08:06:30 2013 +0000

description:
thumbify (part2)

diffstat:

 common/lib/libc/arch/arm/string/strlen_arm.S |  23 ++++++++++++++++-------
 1 files changed, 16 insertions(+), 7 deletions(-)

diffs (65 lines):

diff -r f4764086c17b -r 6c89ef997e6c common/lib/libc/arch/arm/string/strlen_arm.S
--- a/common/lib/libc/arch/arm/string/strlen_arm.S      Tue Aug 20 08:05:49 2013 +0000
+++ b/common/lib/libc/arch/arm/string/strlen_arm.S      Tue Aug 20 08:06:30 2013 +0000
@@ -29,7 +29,11 @@
 
 #include <machine/asm.h>
 
-RCSID("$NetBSD: strlen_arm.S,v 1.4 2013/08/19 01:17:32 matt Exp $")
+RCSID("$NetBSD: strlen_arm.S,v 1.5 2013/08/20 08:06:30 matt Exp $")
+
+#if defined(__thumb__) && !defined(_ARM_ARCH_T2)
+#error Only Thumb2 or ARM supported
+#endif
 
 #ifdef __ARMEL__
 #define        BYTE0   0x000000ff
@@ -63,10 +67,10 @@
        .cfi_offset 5, -4
        .cfi_offset 4, -8
 #endif
-       add     r5, r0, r1              /* get ptr to end of string */
+       adds    r5, r0, r1              /* get ptr to end of string */
        mov     r4, r1                  /* save maxlen */
 #endif
-       add     ip, r0, #4              /* for the final post-inc */
+       adds    r2, r0, #4              /* for the final post-inc */
 1:     tst     r0, #3                  /* test for word alignment */
        beq     .Lpre_main_loop         /*   finally word aligned */
 #ifdef STRNLEN
@@ -74,10 +78,10 @@
        beq     .Lmaxed_out             /*   yes, return maxlen */
 #endif
        ldrb    r3, [r0], #1            /* load a byte */
-       teq     r3, #0                  /* is it 0? */
+       cmp     r3, #0                  /* is it 0? */
        bne     1b                      /*   no, try next byte */
-       sub     ip, ip, #3              /* subtract (4 - the NUL) */
-       sub     r0, r0, ip              /* subtract start */
+       subs    r2, r2, #3              /* subtract (4 - the NUL) */
+       subs    r0, r0, r2              /* subtract start */
 #ifdef STRNLEN
        pop     {r4, r5}                /* restore registers */
 #endif
@@ -127,7 +131,12 @@
        rev     r3, r3                  /* we want this in BE for the CLZ */
 #endif
        clz     r3, r3                  /* count how many leading zeros */
+#ifdef __thumb__
+       lsrs    r3, r3, #3
+       adds    r0, r0, r3              /* divide that by 8 and add to count */
+#else
        add     r0, r0, r3, lsr #3      /* divide that by 8 and add to count */
+#endif
 #else
        /*
         * We encountered a NUL.
@@ -147,7 +156,7 @@
         * start of the string (which also has 4 added to it to compensate for
         * the post-inc.
         */
-       sub     r0, r0, ip              /* subtract start to get length */
+       subs    r0, r0, r2              /* subtract start to get length */
 #ifdef STRNLEN
        cmp     r0, r4                  /* is it larger than maxlen? */
        movgt   r0, r4                  /*   yes, return maxlen */