X-Git-Url: https://asedeno.scripts.mit.edu/gitweb/?a=blobdiff_plain;f=block-sha1%2Fsha1.c;h=d8934757a5e5e259f26c4a09f7ea5d10615df0c1;hb=af24059fa299f1656692f5807eddd3b30b5f3cfb;hp=b715916675469595c0955a15dc0bfde7e6508052;hpb=30d12d4c16abc052e8961c07651f97bea2c061bd;p=git.git diff --git a/block-sha1/sha1.c b/block-sha1/sha1.c index b71591667..c0054a0b0 100644 --- a/block-sha1/sha1.c +++ b/block-sha1/sha1.c @@ -1,93 +1,96 @@ /* - * Based on the Mozilla SHA1 (see mozilla-sha1/sha1.c), - * optimized to do word accesses rather than byte accesses, + * SHA1 routine optimized to do word accesses rather than byte accesses, * and to avoid unnecessary copies into the context array. + * + * This was initially based on the Mozilla SHA1 implementation, although + * none of the original Mozilla code remains. */ -#include -#include +/* this is only to get definitions for memcpy(), ntohl() and htonl() */ +#include "../git-compat-util.h" #include "sha1.h" -/* Hash one 64-byte block of data */ -static void blk_SHA1Block(blk_SHA_CTX *ctx, const unsigned int *data); +#if defined(__GNUC__) && (defined(__i386__) || defined(__x86_64__)) -void blk_SHA1_Init(blk_SHA_CTX *ctx) -{ - ctx->size = 0; - - /* Initialize H with the magic constants (see FIPS180 for constants) - */ - ctx->H[0] = 0x67452301; - ctx->H[1] = 0xefcdab89; - ctx->H[2] = 0x98badcfe; - ctx->H[3] = 0x10325476; - ctx->H[4] = 0xc3d2e1f0; -} - - -void blk_SHA1_Update(blk_SHA_CTX *ctx, const void *data, unsigned long len) -{ - int lenW = ctx->size & 63; +/* + * Force usage of rol or ror by selecting the one with the smaller constant. + * It _can_ generate slightly smaller code (a constant of 1 is special), but + * perhaps more importantly it's possibly faster on any uarch that does a + * rotate with a loop. + */ - ctx->size += len; +#define SHA_ASM(op, x, n) ({ unsigned int __res; __asm__(op " %1,%0":"=r" (__res):"i" (n), "0" (x)); __res; }) +#define SHA_ROL(x,n) SHA_ASM("rol", x, n) +#define SHA_ROR(x,n) SHA_ASM("ror", x, n) - /* Read the data into W and process blocks as they get full - */ - if (lenW) { - int left = 64 - lenW; - if (len < left) - left = len; - memcpy(lenW + (char *)ctx->W, data, left); - lenW = (lenW + left) & 63; - len -= left; - data += left; - if (lenW) - return; - blk_SHA1Block(ctx, ctx->W); - } - while (len >= 64) { - blk_SHA1Block(ctx, data); - data += 64; - len -= 64; - } - if (len) - memcpy(ctx->W, data, len); -} +#else +#define SHA_ROT(X,l,r) (((X) << (l)) | ((X) >> (r))) +#define SHA_ROL(X,n) SHA_ROT(X,n,32-(n)) +#define SHA_ROR(X,n) SHA_ROT(X,32-(n),n) -void blk_SHA1_Final(unsigned char hashout[20], blk_SHA_CTX *ctx) -{ - static const unsigned char pad[64] = { 0x80 }; - unsigned int padlen[2]; - int i; +#endif - /* Pad with a binary 1 (ie 0x80), then zeroes, then length - */ - padlen[0] = htonl(ctx->size >> 29); - padlen[1] = htonl(ctx->size << 3); +/* + * If you have 32 registers or more, the compiler can (and should) + * try to change the array[] accesses into registers. However, on + * machines with less than ~25 registers, that won't really work, + * and at least gcc will make an unholy mess of it. + * + * So to avoid that mess which just slows things down, we force + * the stores to memory to actually happen (we might be better off + * with a 'W(t)=(val);asm("":"+m" (W(t))' there instead, as + * suggested by Artur Skawina - that will also make gcc unable to + * try to do the silly "optimize away loads" part because it won't + * see what the value will be). + * + * Ben Herrenschmidt reports that on PPC, the C version comes close + * to the optimized asm with this (ie on PPC you don't want that + * 'volatile', since there are lots of registers). + * + * On ARM we get the best code generation by forcing a full memory barrier + * between each SHA_ROUND, otherwise gcc happily get wild with spilling and + * the stack frame size simply explode and performance goes down the drain. + */ - i = ctx->size & 63; - blk_SHA1_Update(ctx, pad, 1+ (63 & (55 - i))); - blk_SHA1_Update(ctx, padlen, 8); +#if defined(__i386__) || defined(__x86_64__) + #define setW(x, val) (*(volatile unsigned int *)&W(x) = (val)) +#elif defined(__GNUC__) && defined(__arm__) + #define setW(x, val) do { W(x) = (val); __asm__("":::"memory"); } while (0) +#else + #define setW(x, val) (W(x) = (val)) +#endif - /* Output hash - */ - for (i = 0; i < 5; i++) - ((unsigned int *)hashout)[i] = htonl(ctx->H[i]); -} +/* + * Performance might be improved if the CPU architecture is OK with + * unaligned 32-bit loads and a fast ntohl() is available. + * Otherwise fall back to byte loads and shifts which is portable, + * and is faster on architectures with memory alignment issues. + */ -#if defined(__i386__) || defined(__x86_64__) +#if defined(__i386__) || defined(__x86_64__) || \ + defined(_M_IX86) || defined(_M_X64) || \ + defined(__ppc__) || defined(__ppc64__) || \ + defined(__powerpc__) || defined(__powerpc64__) || \ + defined(__s390__) || defined(__s390x__) -#define SHA_ASM(op, x, n) ({ unsigned int __res; __asm__(op " %1,%0":"=r" (__res):"i" (n), "0" (x)); __res; }) -#define SHA_ROL(x,n) SHA_ASM("rol", x, n) -#define SHA_ROR(x,n) SHA_ASM("ror", x, n) +#define get_be32(p) ntohl(*(unsigned int *)(p)) +#define put_be32(p, v) do { *(unsigned int *)(p) = htonl(v); } while (0) #else -#define SHA_ROT(X,l,r) (((X) << (l)) | ((X) >> (r))) -#define SHA_ROL(X,n) SHA_ROT(X,n,32-(n)) -#define SHA_ROR(X,n) SHA_ROT(X,32-(n),n) +#define get_be32(p) ( \ + (*((unsigned char *)(p) + 0) << 24) | \ + (*((unsigned char *)(p) + 1) << 16) | \ + (*((unsigned char *)(p) + 2) << 8) | \ + (*((unsigned char *)(p) + 3) << 0) ) +#define put_be32(p, v) do { \ + unsigned int __v = (v); \ + *((unsigned char *)(p) + 0) = __v >> 24; \ + *((unsigned char *)(p) + 1) = __v >> 16; \ + *((unsigned char *)(p) + 2) = __v >> 8; \ + *((unsigned char *)(p) + 3) = __v >> 0; } while (0) #endif @@ -98,13 +101,13 @@ void blk_SHA1_Final(unsigned char hashout[20], blk_SHA_CTX *ctx) * Where do we get the source from? The first 16 iterations get it from * the input data, the next mix it from the 512-bit array. */ -#define SHA_SRC(t) htonl(data[t]) +#define SHA_SRC(t) get_be32(data + t) #define SHA_MIX(t) SHA_ROL(W(t+13) ^ W(t+8) ^ W(t+2) ^ W(t), 1) #define SHA_ROUND(t, input, fn, constant, A, B, C, D, E) do { \ - unsigned int TEMP = input(t); W(t) = TEMP; \ - TEMP += E + SHA_ROL(A,5) + (fn) + (constant); \ - B = SHA_ROR(B, 2); E = TEMP; } while (0) + unsigned int TEMP = input(t); setW(t, TEMP); \ + E += TEMP + SHA_ROL(A,5) + (fn) + (constant); \ + B = SHA_ROR(B, 2); } while (0) #define T_0_15(t, A, B, C, D, E) SHA_ROUND(t, SHA_SRC, (((C^D)&B)^D) , 0x5a827999, A, B, C, D, E ) #define T_16_19(t, A, B, C, D, E) SHA_ROUND(t, SHA_MIX, (((C^D)&B)^D) , 0x5a827999, A, B, C, D, E ) @@ -112,7 +115,7 @@ void blk_SHA1_Final(unsigned char hashout[20], blk_SHA_CTX *ctx) #define T_40_59(t, A, B, C, D, E) SHA_ROUND(t, SHA_MIX, ((B&C)+(D&(B^C))) , 0x8f1bbcdc, A, B, C, D, E ) #define T_60_79(t, A, B, C, D, E) SHA_ROUND(t, SHA_MIX, (B^C^D) , 0xca62c1d6, A, B, C, D, E ) -static void blk_SHA1Block(blk_SHA_CTX *ctx, const unsigned int *data) +static void blk_SHA1_Block(blk_SHA_CTX *ctx, const unsigned int *data) { unsigned int A,B,C,D,E; unsigned int array[16]; @@ -219,3 +222,62 @@ static void blk_SHA1Block(blk_SHA_CTX *ctx, const unsigned int *data) ctx->H[3] += D; ctx->H[4] += E; } + +void blk_SHA1_Init(blk_SHA_CTX *ctx) +{ + ctx->size = 0; + + /* Initialize H with the magic constants (see FIPS180 for constants) */ + ctx->H[0] = 0x67452301; + ctx->H[1] = 0xefcdab89; + ctx->H[2] = 0x98badcfe; + ctx->H[3] = 0x10325476; + ctx->H[4] = 0xc3d2e1f0; +} + +void blk_SHA1_Update(blk_SHA_CTX *ctx, const void *data, unsigned long len) +{ + unsigned int lenW = ctx->size & 63; + + ctx->size += len; + + /* Read the data into W and process blocks as they get full */ + if (lenW) { + unsigned int left = 64 - lenW; + if (len < left) + left = len; + memcpy(lenW + (char *)ctx->W, data, left); + lenW = (lenW + left) & 63; + len -= left; + data = ((const char *)data + left); + if (lenW) + return; + blk_SHA1_Block(ctx, ctx->W); + } + while (len >= 64) { + blk_SHA1_Block(ctx, data); + data = ((const char *)data + 64); + len -= 64; + } + if (len) + memcpy(ctx->W, data, len); +} + +void blk_SHA1_Final(unsigned char hashout[20], blk_SHA_CTX *ctx) +{ + static const unsigned char pad[64] = { 0x80 }; + unsigned int padlen[2]; + int i; + + /* Pad with a binary 1 (ie 0x80), then zeroes, then length */ + padlen[0] = htonl((uint32_t)(ctx->size >> 29)); + padlen[1] = htonl((uint32_t)(ctx->size << 3)); + + i = ctx->size & 63; + blk_SHA1_Update(ctx, pad, 1+ (63 & (55 - i))); + blk_SHA1_Update(ctx, padlen, 8); + + /* Output hash */ + for (i = 0; i < 5; i++) + put_be32(hashout + i*4, ctx->H[i]); +}