[PATCH 4/7] block-sha1: re-use the temporary array as we calculate the SHA1
- From
Linus Torvalds <torvalds@linux-foundation.org>
- Date
- Aug 6, 2009, 15:20 UTC
- Message-ID
- <alpine.LFD.2.01.0908060818220.3390@localhost.localdomain>
- In-Reply-To
- <alpine.LFD.2.01.0908060816550.3390@localhost.localdomain>
From: Linus Torvalds <torvalds@linux-foundation.org> Date: Wed, 5 Aug 2009 20:49:41 -0700 Subject: [PATCH 4/7] 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 <torvalds@linux-foundation.org> ---
This gets rid of the annoying pre-initialization and its need for that extra space. We can dynamically iterate over a 512-bit circular buffer instead.
block-sha1/sha1.c | 28 ++++++++++++++++------------ 1 files changed, 16 insertions(+), 12 deletions(-)
diff --git a/block-sha1/sha1.c b/block-sha1/sha1.c index 39a5bbb..80193d4 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);
-- 1.6.4.31.g154b2.dirty