a59e5a7d0
Denys Vlasenko
2023-03-29
Subject
libbb/sha: do not read shaNI variable twice, and factor out its setting
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Commit Diff GitHub →
libbb/hash_md5_sha.c+16 -12
| @@ -23,6 +23,14 @@ static void cpuid(unsigned *eax, unsigned *ebx, unsigned *ecx, unsigned *edx) | |
| ); | |
| } | |
| static smallint shaNI; | |
| + | static int get_shaNI(void) |
| + | { |
| + | unsigned eax = 7, ebx = ebx, ecx = 0, edx = edx; |
| + | cpuid(&eax, &ebx, &ecx, &edx); |
| + | ebx = ((ebx >> 28) & 2) - 1; /* bit 29 -> 1 or -1 */ |
| + | shaNI = (int)ebx; |
| + | return (int)ebx; |
| + | } |
| void FAST_FUNC sha1_process_block64_shaNI(sha1_ctx_t *ctx); | |
| void FAST_FUNC sha256_process_block64_shaNI(sha256_ctx_t *ctx); | |
| # if defined(__i386__) | |
| @@ -1175,12 +1183,10 @@ void FAST_FUNC sha1_begin(sha1_ctx_t *ctx) | |
| #if ENABLE_SHA1_HWACCEL | |
| # if defined(__GNUC__) && (defined(__i386__) || defined(__x86_64__)) | |
| { | |
| - | if (!shaNI) { |
| - | unsigned eax = 7, ebx = ebx, ecx = 0, edx = edx; |
| - | cpuid(&eax, &ebx, &ecx, &edx); |
| - | shaNI = ((ebx >> 28) & 2) - 1; /* bit 29 -> 1 or -1 */ |
| - | } |
| - | if (shaNI > 0) |
| + | int ni = shaNI; |
| + | if (!ni) |
| + | ni = get_shaNI(); |
| + | if (ni > 0) |
| ctx->process_block = sha1_process_block64_shaNI; | |
| } | |
| # endif | |
| @@ -1229,12 +1235,10 @@ void FAST_FUNC sha256_begin(sha256_ctx_t *ctx) | |
| #if ENABLE_SHA256_HWACCEL | |
| # if defined(__GNUC__) && (defined(__i386__) || defined(__x86_64__)) | |
| { | |
| - | if (!shaNI) { |
| - | unsigned eax = 7, ebx = ebx, ecx = 0, edx = edx; |
| - | cpuid(&eax, &ebx, &ecx, &edx); |
| - | shaNI = ((ebx >> 28) & 2) - 1; /* bit 29 -> 1 or -1 */ |
| - | } |
| - | if (shaNI > 0) |
| + | int ni = shaNI; |
| + | if (!ni) |
| + | ni = get_shaNI(); |
| + | if (ni > 0) |
| ctx->process_block = sha256_process_block64_shaNI; | |
| } | |
| # endif | |