[src/trunk]: src/common/lib/libc/arch/arm/string Add END() and clarify thumb/arm

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

details:   https://anonhg.NetBSD.org/src/rev/86196ec2762f
branches:  trunk
changeset: 789440:86196ec2762f
user:      matt <matt%NetBSD.org@localhost>
date:      Mon Aug 19 02:55:19 2013 +0000

description:
Add END() and clarify thumb/arm

diffstat:

 common/lib/libc/arch/arm/string/ffs.S |  17 ++++++++++++-----
 1 files changed, 12 insertions(+), 5 deletions(-)

diffs (51 lines):

diff -r 5727ebeabc49 -r 86196ec2762f common/lib/libc/arch/arm/string/ffs.S
--- a/common/lib/libc/arch/arm/string/ffs.S     Mon Aug 19 02:54:02 2013 +0000
+++ b/common/lib/libc/arch/arm/string/ffs.S     Mon Aug 19 02:55:19 2013 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: ffs.S,v 1.3 2013/08/11 05:02:35 matt Exp $     */
+/*     $NetBSD: ffs.S,v 1.4 2013/08/19 02:55:19 matt Exp $     */
 /*
  * Copyright (c) 2001 Christopher Gilbert
  * All rights reserved.
@@ -30,7 +30,7 @@
 
 #include <machine/asm.h>
 
-RCSID("$NetBSD: ffs.S,v 1.3 2013/08/11 05:02:35 matt Exp $")
+RCSID("$NetBSD: ffs.S,v 1.4 2013/08/19 02:55:19 matt Exp $")
 
 /*
  * ffs - find first set bit, this algorithm isolates the first set
@@ -45,17 +45,23 @@
  * 16 Feb 1994.
  */
 WEAK_ALIAS(__ffssi2,ffs)
+#if (defined(_ARM_ARCH_5) && !defined(__thumb__)) || defined(_ARM_ARCH_T2)
+#if defined(_ARM_ARCH_T2)
 ENTRY(ffs)
-#ifdef _ARM_ARCH_5
+#else
+ARM_ENTRY(ffs)
+#endif
        /* (X & -X) gives LSB or zero.  */
-       rsb     r1, r0, #0
+       neg     r1, r0
        and     r0, r0, r1
        clz     r0, r0
        rsb     r0, r0, #32
        RET
+END(ffs)
 #else
+ARM_ENTRY(ffs)
        /* Standard trick to isolate bottom bit in r0 or 0 if r0 = 0 on entry */
-       rsb     r1, r0, #0
+       neg     r1, r0
        ands    r0, r0, r1
        /*
         * now r0 has at most one set bit, call this X
@@ -82,4 +88,5 @@
        .byte   10,  0,  0, 25,  0,  0, 21, 27  /* 40-47 */
        .byte   31,  0,  0,  0,  0, 24,  0, 20  /* 48-55 */
        .byte   30,  0, 23, 19, 29, 18, 17,  0  /* 56-63 */
+END(ffs)
 #endif