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libbb/sha: do not read shaNI variable twice, and factor out its setting

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My gcc inlines both calls, so instead of "-20 bytes" I get only this:

function                                             old     new   delta
sha256_begin                                          84      83      -1
sha1_begin                                           114     111      -3
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 0/2 up/down: 0/-4)               Total: -4 bytes

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
This commit is contained in:
Denys Vlasenko 2023-03-29 15:44:08 +02:00
parent bd76b75f72
commit a59e5a7d08
1 changed files with 16 additions and 12 deletions
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28
libbb/hash_md5_sha.c
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@ -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