| commit | 39ddb88ed4aa8d3eaf8ec7b8476996a94ae5bd07 | |
| author | Bin Liu <binliu@fb.com> | |
| Wed, 11 Nov 2015 06:36:36 +0000 (10 22:36 -0800) | ||
| committer | hhvm-bot <hhvm-bot@fb.com> | |
| Wed, 11 Nov 2015 07:00:57 +0000 (10 23:00 -0800) | ||
| tree | 32d0e75192b5a79d70ec5f84f5e7a88da4432c55 | treesnapshot (tar.gz zip) |
| parent | 68a474932048e790eace00ccd206fc13a9603983 | commitdiff |
rewrite strcmp in assembly
Summary: Need SSE 4.2.
One thing to note is that we do unsigned comparison when deciding whether to return negative or positive integer.
Some versions of glibc seems to do signed comparison. But C99 standard explicitly says unsigned. Maybe this doesn't matter at all.
Reviewed By: ottoni
Differential Revision: D2614423
fb-gh-sync-id: 67de72123006ee238ed1ccf04f0255c9b14c162b
Summary: Need SSE 4.2.
One thing to note is that we do unsigned comparison when deciding whether to return negative or positive integer.
Some versions of glibc seems to do signed comparison. But C99 standard explicitly says unsigned. Maybe this doesn't matter at all.
Reviewed By: ottoni
Differential Revision: D2614423
fb-gh-sync-id: 67de72123006ee238ed1ccf04f0255c9b14c162b
| hphp/util/strcmp-sse42.S | [new file with mode: 0644] | blob |