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torvaldsgitster
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block-sha1: make the 'ntohl()' part of the first SHA1 loop
This helps a teeny bit. But what I -really- want to do is to avoid the whole 80-array loop, and do the xor updates as I go along.. Signed-off-by: Linus Torvalds <[email protected]> Signed-off-by: Junio C Hamano <[email protected]>
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block-sha1/sha1.c

Lines changed: 16 additions & 12 deletions
Original file line numberDiff line numberDiff line change
@@ -100,27 +100,31 @@ static void blk_SHA1Block(blk_SHA_CTX *ctx, const unsigned int *data)
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unsigned int A,B,C,D,E,TEMP;
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unsigned int W[80];
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103-
for (t = 0; t < 16; t++)
104-
W[t] = htonl(data[t]);
105-
106-
/* Unroll it? */
107-
for (t = 16; t <= 79; t++)
108-
W[t] = SHA_ROL(W[t-3] ^ W[t-8] ^ W[t-14] ^ W[t-16], 1);
109-
110103
A = ctx->H[0];
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B = ctx->H[1];
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C = ctx->H[2];
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D = ctx->H[3];
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E = ctx->H[4];
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116-
#define T_0_19(t) \
109+
#define T_0_15(t) \
110+
TEMP = htonl(data[t]); W[t] = TEMP; \
111+
TEMP += SHA_ROL(A,5) + (((C^D)&B)^D) + E + 0x5a827999; \
112+
E = D; D = C; C = SHA_ROR(B, 2); B = A; A = TEMP; \
113+
114+
T_0_15( 0); T_0_15( 1); T_0_15( 2); T_0_15( 3); T_0_15( 4);
115+
T_0_15( 5); T_0_15( 6); T_0_15( 7); T_0_15( 8); T_0_15( 9);
116+
T_0_15(10); T_0_15(11); T_0_15(12); T_0_15(13); T_0_15(14);
117+
T_0_15(15);
118+
119+
/* Unroll it? */
120+
for (t = 16; t <= 79; t++)
121+
W[t] = SHA_ROL(W[t-3] ^ W[t-8] ^ W[t-14] ^ W[t-16], 1);
122+
123+
#define T_16_19(t) \
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TEMP = SHA_ROL(A,5) + (((C^D)&B)^D) + E + W[t] + 0x5a827999; \
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E = D; D = C; C = SHA_ROR(B, 2); B = A; A = TEMP;
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120-
T_0_19( 0); T_0_19( 1); T_0_19( 2); T_0_19( 3); T_0_19( 4);
121-
T_0_19( 5); T_0_19( 6); T_0_19( 7); T_0_19( 8); T_0_19( 9);
122-
T_0_19(10); T_0_19(11); T_0_19(12); T_0_19(13); T_0_19(14);
123-
T_0_19(15); T_0_19(16); T_0_19(17); T_0_19(18); T_0_19(19);
127+
T_16_19(16); T_16_19(17); T_16_19(18); T_16_19(19);
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125129
#define T_20_39(t) \
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TEMP = SHA_ROL(A,5) + (B^C^D) + E + W[t] + 0x6ed9eba1; \

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