[src/trunk]: src/common/lib/libc/arch/arm/atomic Use subs/sbc

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

details:   https://anonhg.NetBSD.org/src/rev/85198fdbcaaa
branches:  trunk
changeset: 789177:85198fdbcaaa
user:      matt <matt%NetBSD.org@localhost>
date:      Sat Aug 10 18:40:19 2013 +0000

description:
Use subs/sbc
Use push/pop
Don't adjust return for atomic_dec_64 since it's void and returns nothing

diffstat:

 common/lib/libc/arch/arm/atomic/atomic_dec_64.S |  24 ++++++++++--------------
 1 files changed, 10 insertions(+), 14 deletions(-)

diffs (52 lines):

diff -r f5b58353f401 -r 85198fdbcaaa common/lib/libc/arch/arm/atomic/atomic_dec_64.S
--- a/common/lib/libc/arch/arm/atomic/atomic_dec_64.S   Sat Aug 10 18:39:48 2013 +0000
+++ b/common/lib/libc/arch/arm/atomic/atomic_dec_64.S   Sat Aug 10 18:40:19 2013 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: atomic_dec_64.S,v 1.2 2012/09/13 00:36:12 matt Exp $   */
+/*     $NetBSD: atomic_dec_64.S,v 1.3 2013/08/10 18:40:19 matt Exp $   */
 /*-
  * Copyright (c) 2012 The NetBSD Foundation, Inc.
  * All rights reserved.
@@ -33,33 +33,29 @@
 #ifdef _ARM_ARCH_6
 
 ENTRY_NP(_atomic_dec_64)
-       mvn     r2, #0
        mov     r3, r0                  /* need r0 for return value */
 1:     ldrexd  r0, [r3]                /* load old value (return value) */
-       adds    LO, LO, r2              /* calculate new value */
-       adc     HI, HI, r2              /* calculate new value */
-       strexd  ip, r0, [r3]            /* try to store */
-       cmp     ip, #0                  /*   succeed? */
+       subs    LO, LO, #1              /* calculate new value */
+       sbc     HI, HI, #0              /* calculate new value */
+       strexd  r2, r0, [r3]            /* try to store */
+       cmp     r2, #0                  /*   succeed? */
        bne     1b                      /*     no, try again? */
 #ifdef _ARM_ARCH_7
        dmb
 #else
        mcr     p15, 0, ip, c7, c10, 5  /* data memory barrier */
 #endif
-       adds    LO, LO, #1
-       adc     HI, HI, #0
-       RET                             /* return old value */
+       RET
        END(_atomic_dec_64)
 ATOMIC_OP_ALIAS(atomic_dec_64,_atomic_dec_64)
 
 ENTRY_NP(_atomic_dec_64_nv)
-       mvn     r2, #0
        mov     r3, r0                  /* need r0 for return value */
 1:     ldrexd  r0, [r3]                /* load old value */
-       adds    LO, LO, r2              /* calculate new value */
-       adc     HI, HI, r2              /* calculate new value */
-       strexd  ip, r0, [r3]            /* try to store */
-       cmp     ip, #0                  /*   succeed? */
+       subs    LO, LO, #1              /* calculate new value */
+       sbc     HI, HI, #0              /* calculate new value */
+       strexd  r2, r0, [r3]            /* try to store */
+       cmp     r2, #0                  /*   succeed? */
        bne     1b                      /*     no, try again? */
 #ifdef _ARM_ARCH_7
        dmb