| commit | a9477d1e0c6fd0e47e637d051e7b9e2a5d9af517 | [log] [tgz] |
|---|---|---|
| author | Lasse Collin <lasse.collin@tukaani.org> | Sun Aug 03 21:08:12 2014 +0300 |
| committer | Lasse Collin <lasse.collin@tukaani.org> | Sun Aug 03 21:08:12 2014 +0300 |
| tree | 2775facf874762fff0d2f2fafacbbe2b70f07327 | |
| parent | 5a76c7c8ee9a0afbeedb1c211db9224260404347 [diff] |
liblzma: SHA-256: Optimize the way rotations are done.
This looks weird because the rotations become sequential,
but it helps quite a bit on both 32-bit and 64-bit x86:
- It requires fewer instructions on two-operand
instruction sets like x86.
- It requires one register less which matters especially
on 32-bit x86.
I hope this doesn't hurt other archs.
I didn't invent this idea myself, but I don't remember where
I saw it first.