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block-sha1: Use '(B&C)+(D&(B^C))' instead of '(B&C)|(D&(B|C))' in round 3

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It's an equivalent expression, but the '+' gives us some freedom in
instruction selection (for example, we can use 'lea' rather than 'add'),
and associates with the other additions around it to give some minor
scheduling freedom.

Suggested-by: linux@horizon.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This commit is contained in:
Linus Torvalds 2009-08-06 07:27:57 -07:00 committed by Junio C Hamano
parent ab14c823df
commit e869e113c8
1 changed files with 1 additions and 1 deletions
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block-sha1/sha1.c
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@ -112,7 +112,7 @@ void blk_SHA1_Final(unsigned char hashout[20], blk_SHA_CTX *ctx)
#define T_0_15(t) SHA_ROUND(t, SHA_SRC, (((C^D)&B)^D) , 0x5a827999 )
#define T_16_19(t) SHA_ROUND(t, SHA_MIX, (((C^D)&B)^D) , 0x5a827999 )
#define T_20_39(t) SHA_ROUND(t, SHA_MIX, (B^C^D) , 0x6ed9eba1 )
#define T_40_59(t) SHA_ROUND(t, SHA_MIX, ((B&C)|(D&(B|C))) , 0x8f1bbcdc )
#define T_40_59(t) SHA_ROUND(t, SHA_MIX, ((B&C)+(D&(B^C))) , 0x8f1bbcdc )
#define T_60_79(t) SHA_ROUND(t, SHA_MIX, (B^C^D) , 0xca62c1d6 )
static void blk_SHA1Block(blk_SHA_CTX *ctx, const unsigned int *data)