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authorMikulas Patocka <mpatocka@redhat.com>2010-08-18 08:03:37 +0000
committerDavid S. Miller <davem@davemloft.net>2010-08-18 22:51:08 -0700
commit6ec274750c99448c3412bbc10c97ce0c993f8a4e (patch)
tree1ec5f1b5a964d893dee6f2b4ba3eb691a3dc78a7 /arch/sparc/lib
parent9b3bb86acabe0c05923cea1ed3b0bee9439fef4b (diff)
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sparc64: simple microoptimizations for atomic functions
Simple microoptimizations for sparc64 atomic functions: Save one instruction by using a delay slot. Use %g1 instead of %g7, because %g1 is written earlier. Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'arch/sparc/lib')
-rw-r--r--arch/sparc/lib/atomic_64.S20
1 files changed, 8 insertions, 12 deletions
diff --git a/arch/sparc/lib/atomic_64.S b/arch/sparc/lib/atomic_64.S
index 0268210ca16..703c9c3935b 100644
--- a/arch/sparc/lib/atomic_64.S
+++ b/arch/sparc/lib/atomic_64.S
@@ -52,10 +52,9 @@ atomic_add_ret: /* %o0 = increment, %o1 = atomic_ptr */
cas [%o1], %g1, %g7
cmp %g1, %g7
bne,pn %icc, 2f
- add %g7, %o0, %g7
- sra %g7, 0, %o0
+ add %g1, %o0, %g1
retl
- nop
+ sra %g1, 0, %o0
2: BACKOFF_SPIN(%o2, %o3, 1b)
.size atomic_add_ret, .-atomic_add_ret
@@ -68,10 +67,9 @@ atomic_sub_ret: /* %o0 = decrement, %o1 = atomic_ptr */
cas [%o1], %g1, %g7
cmp %g1, %g7
bne,pn %icc, 2f
- sub %g7, %o0, %g7
- sra %g7, 0, %o0
+ sub %g1, %o0, %g1
retl
- nop
+ sra %g1, 0, %o0
2: BACKOFF_SPIN(%o2, %o3, 1b)
.size atomic_sub_ret, .-atomic_sub_ret
@@ -114,10 +112,9 @@ atomic64_add_ret: /* %o0 = increment, %o1 = atomic_ptr */
casx [%o1], %g1, %g7
cmp %g1, %g7
bne,pn %xcc, 2f
- add %g7, %o0, %g7
- mov %g7, %o0
- retl
nop
+ retl
+ add %g1, %o0, %o0
2: BACKOFF_SPIN(%o2, %o3, 1b)
.size atomic64_add_ret, .-atomic64_add_ret
@@ -130,9 +127,8 @@ atomic64_sub_ret: /* %o0 = decrement, %o1 = atomic_ptr */
casx [%o1], %g1, %g7
cmp %g1, %g7
bne,pn %xcc, 2f
- sub %g7, %o0, %g7
- mov %g7, %o0
- retl
nop
+ retl
+ sub %g1, %o0, %o0
2: BACKOFF_SPIN(%o2, %o3, 1b)
.size atomic64_sub_ret, .-atomic64_sub_ret