diff options
| author | Wilco Dijkstra <Wilco.Dijkstra@arm.com> | 2018-11-06 14:42:10 +0000 |
|---|---|---|
| committer | Richard Earnshaw <Richard.Earnshaw@arm.com> | 2018-11-06 14:59:51 +0000 |
| commit | d80db600664bec381230be85955b54884f21a619 (patch) | |
| tree | 3a3c9725ac7206987203f7eeefe1a9f209d30c3e | |
| parent | 535903696c339b71edd3575ab44bbf2e5eab689a (diff) | |
| download | newlib-d80db600664bec381230be85955b54884f21a619.zip newlib-d80db600664bec381230be85955b54884f21a619.tar.gz newlib-d80db600664bec381230be85955b54884f21a619.tar.bz2 | |
Adjust writeback in non-zero memset
This fixes an ineffiency in the non-zero memset. Delaying the writeback
until the end of the loop is slightly faster on some cores - this shows
~5% performance gain on Cortex-A53 when doing large non-zero memsets.
Tested against the GLIBC testsuite.
| -rw-r--r-- | newlib/libc/machine/aarch64/memset.S | 6 |
1 files changed, 3 insertions, 3 deletions
diff --git a/newlib/libc/machine/aarch64/memset.S b/newlib/libc/machine/aarch64/memset.S index 799e7b7..7c8fe58 100644 --- a/newlib/libc/machine/aarch64/memset.S +++ b/newlib/libc/machine/aarch64/memset.S @@ -142,10 +142,10 @@ L(set_long): b.eq L(try_zva) L(no_zva): sub count, dstend, dst /* Count is 16 too large. */ - add dst, dst, 16 + sub dst, dst, 16 /* Dst is biased by -32. */ sub count, count, 64 + 16 /* Adjust count and bias for loop. */ -1: stp q0, q0, [dst], 64 - stp q0, q0, [dst, -32] +1: stp q0, q0, [dst, 32] + stp q0, q0, [dst, 64]! L(tail64): subs count, count, 64 b.hi 1b |