From: Linus Torvalds Date: Thu, 6 Aug 2009 03:49:41 +0000 (-0700) Subject: block-sha1: re-use the temporary array as we calculate the SHA1 X-Git-Tag: v1.6.5-rc0~30^2~15 X-Git-Url: https://git.tokkee.org/?a=commitdiff_plain;h=7b5075fcfb069fc36ba4cfe5567234974793ab58;p=git.git block-sha1: re-use the temporary array as we calculate the SHA1 The mozilla-SHA1 code did this 80-word array for the 80 iterations. But the SHA1 state is really just 512 bits, and you can actually keep it in a kind of "circular queue" of just 16 words instead. This requires us to do the xor updates as we go along (rather than as a pre-phase), but that's really what we want to do anyway. This gets me really close to the OpenSSL performance on my Nehalem. Look ma, all C code (ok, there's the rol/ror hack, but that one doesn't strictly even matter on my Nehalem, it's just a local optimization). Signed-off-by: Linus Torvalds Signed-off-by: Junio C Hamano --- diff --git a/block-sha1/sha1.c b/block-sha1/sha1.c index 13da511b7..8c4c216f9 100644 --- a/block-sha1/sha1.c +++ b/block-sha1/sha1.c @@ -96,9 +96,8 @@ void blk_SHA1_Final(unsigned char hashout[20], blk_SHA_CTX *ctx) static void blk_SHA1Block(blk_SHA_CTX *ctx, const unsigned int *data) { - int t; unsigned int A,B,C,D,E,TEMP; - unsigned int W[80]; + unsigned int array[16]; A = ctx->H[0]; B = ctx->H[1]; @@ -107,8 +106,8 @@ static void blk_SHA1Block(blk_SHA_CTX *ctx, const unsigned int *data) E = ctx->H[4]; #define T_0_15(t) \ - TEMP = htonl(data[t]); W[t] = TEMP; \ - TEMP += SHA_ROL(A,5) + (((C^D)&B)^D) + E + 0x5a827999; \ + TEMP = htonl(data[t]); array[t] = TEMP; \ + TEMP += SHA_ROL(A,5) + (((C^D)&B)^D) + E + 0x5a827999; \ E = D; D = C; C = SHA_ROR(B, 2); B = A; A = TEMP; \ T_0_15( 0); T_0_15( 1); T_0_15( 2); T_0_15( 3); T_0_15( 4); @@ -116,18 +115,21 @@ static void blk_SHA1Block(blk_SHA_CTX *ctx, const unsigned int *data) T_0_15(10); T_0_15(11); T_0_15(12); T_0_15(13); T_0_15(14); T_0_15(15); - /* Unroll it? */ - for (t = 16; t <= 79; t++) - W[t] = SHA_ROL(W[t-3] ^ W[t-8] ^ W[t-14] ^ W[t-16], 1); +/* This "rolls" over the 512-bit array */ +#define W(x) (array[(x)&15]) +#define SHA_XOR(t) \ + TEMP = SHA_ROL(W(t+13) ^ W(t+8) ^ W(t+2) ^ W(t), 1); W(t) = TEMP; #define T_16_19(t) \ - TEMP = SHA_ROL(A,5) + (((C^D)&B)^D) + E + W[t] + 0x5a827999; \ - E = D; D = C; C = SHA_ROR(B, 2); B = A; A = TEMP; + SHA_XOR(t); \ + TEMP += SHA_ROL(A,5) + (((C^D)&B)^D) + E + 0x5a827999; \ + E = D; D = C; C = SHA_ROR(B, 2); B = A; A = TEMP; \ T_16_19(16); T_16_19(17); T_16_19(18); T_16_19(19); #define T_20_39(t) \ - TEMP = SHA_ROL(A,5) + (B^C^D) + E + W[t] + 0x6ed9eba1; \ + SHA_XOR(t); \ + TEMP += SHA_ROL(A,5) + (B^C^D) + E + 0x6ed9eba1; \ E = D; D = C; C = SHA_ROR(B, 2); B = A; A = TEMP; T_20_39(20); T_20_39(21); T_20_39(22); T_20_39(23); T_20_39(24); @@ -136,7 +138,8 @@ static void blk_SHA1Block(blk_SHA_CTX *ctx, const unsigned int *data) T_20_39(35); T_20_39(36); T_20_39(37); T_20_39(38); T_20_39(39); #define T_40_59(t) \ - TEMP = SHA_ROL(A,5) + ((B&C)|(D&(B|C))) + E + W[t] + 0x8f1bbcdc; \ + SHA_XOR(t); \ + TEMP += SHA_ROL(A,5) + ((B&C)|(D&(B|C))) + E + 0x8f1bbcdc; \ E = D; D = C; C = SHA_ROR(B, 2); B = A; A = TEMP; T_40_59(40); T_40_59(41); T_40_59(42); T_40_59(43); T_40_59(44); @@ -145,7 +148,8 @@ static void blk_SHA1Block(blk_SHA_CTX *ctx, const unsigned int *data) T_40_59(55); T_40_59(56); T_40_59(57); T_40_59(58); T_40_59(59); #define T_60_79(t) \ - TEMP = SHA_ROL(A,5) + (B^C^D) + E + W[t] + 0xca62c1d6; \ + SHA_XOR(t); \ + TEMP += SHA_ROL(A,5) + (B^C^D) + E + 0xca62c1d6; \ E = D; D = C; C = SHA_ROR(B, 2); B = A; A = TEMP; T_60_79(60); T_60_79(61); T_60_79(62); T_60_79(63); T_60_79(64);