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| author | Lasse Collin <lasse.collin@tukaani.org> | 2014-08-03 21:32:25 +0300 |
|---|---|---|
| committer | Lasse Collin <lasse.collin@tukaani.org> | 2014-08-03 21:32:25 +0300 |
| commit | 5dcffdbcc23a68abc3ac3539b30be71bc9b5af84 (patch) | |
| tree | 7c3ae0e92d75e1f3c9afd338fd74ed67f560670d | |
| parent | liblzma: SHA-256: Optimize the way rotations are done. (diff) | |
| download | xz-5dcffdbcc23a68abc3ac3539b30be71bc9b5af84.tar.xz | |
liblzma: SHA-256: Optimize the Maj macro slightly.
The Maj macro is used where multiple things are added
together, so making Maj a sum of two expressions allows
some extra freedom for the compiler to schedule the
instructions.
I learned this trick from
<http://www.hackersdelight.org/corres.txt>.
| -rw-r--r-- | src/liblzma/check/sha256.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/src/liblzma/check/sha256.c b/src/liblzma/check/sha256.c index e0e2f10b..5eede5ce 100644 --- a/src/liblzma/check/sha256.c +++ b/src/liblzma/check/sha256.c @@ -36,7 +36,7 @@ rotr_32(uint32_t num, unsigned amount) + s0(W[(i - 15) & 15])) #define Ch(x, y, z) (z ^ (x & (y ^ z))) -#define Maj(x, y, z) ((x & y) | (z & (x | y))) +#define Maj(x, y, z) ((x & (y ^ z)) + (y & z)) #define a(i) T[(0 - i) & 7] #define b(i) T[(1 - i) & 7] |