block-sha1: Use '(B&C)+(D&(B^C))' instead of '(B&C)|(D&(B|C))' in round 3
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>
Linus Torvalds committed
Aug 6, 2009 at 07:27 UTC
e869e113c8f91999f9a433436e0b863fe2727b61
1 file changed
+1
-1
block-sha1/sha1.c
+1
-1
@@ -112,7 +112,7 @@ void blk_SHA1_Final(unsigned char hashout[20], blk_SHA_CTX *ctx)
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#define T_0_15(t) SHA_ROUND(t, SHA_SRC, (((C^D)&B)^D) , 0x5a827999 )
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#define T_16_19(t) SHA_ROUND(t, SHA_MIX, (((C^D)&B)^D) , 0x5a827999 )
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#define T_20_39(t) SHA_ROUND(t, SHA_MIX, (B^C^D) , 0x6ed9eba1 )
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-#define T_40_59(t) SHA_ROUND(t, SHA_MIX, ((B&C)|(D&(B|C))) , 0x8f1bbcdc )
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+#define T_40_59(t) SHA_ROUND(t, SHA_MIX, ((B&C)+(D&(B^C))) , 0x8f1bbcdc )
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#define T_60_79(t) SHA_ROUND(t, SHA_MIX, (B^C^D) , 0xca62c1d6 )
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static void blk_SHA1Block(blk_SHA_CTX *ctx, const unsigned int *data)