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@xxxxxxxxxx> --- arch/sparc/lib/atomic_64.S | 20 ++++++++------------ 1 file changed, 8 insertions(+), 12 deletions(-) Index: linux-2.6.35-preempt/arch/sparc/lib/atomic_64.S =================================================================== --- linux-2.6.35-preempt.orig/arch/sparc/lib/atomic_64.S 2010-08-18 15:10:47.000000000 +0200 +++ linux-2.6.35-preempt/arch/sparc/lib/atomic_64.S 2010-08-18 19:40:25.000000000 +0200 @@ -52,10 +52,9 @@ atomic_add_ret: /* %o0 = increment, %o1 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 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, %o 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, %o 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 -- To unsubscribe from this list: send the line "unsubscribe sparclinux" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
