From fa9b98fdab5b57ecb4dd3d6c2489e262af458c44 Mon Sep 17 00:00:00 2001 From: Nicolas Pitre Date: Sun, 13 Nov 2005 11:17:33 +1100 Subject: [PATCH] [CRYPTO] sha1: Avoid shifting count left and right This patch avoids shifting the count left and right needlessly for each call to sha1_update(). It instead can be done only once at the end in sha1_final(). Keeping the previous test example (sha1_update() successively called with len=64), a 1.3% performance increase can be observed on i386, or 0.2% on ARM. The generated code is also smaller on ARM. Signed-off-by: Nicolas Pitre Signed-off-by: Herbert Xu --- crypto/sha1.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/crypto/sha1.c b/crypto/sha1.c index 7b1abca29365..8048e2dd3c14 100644 --- a/crypto/sha1.c +++ b/crypto/sha1.c @@ -52,8 +52,8 @@ static void sha1_update(void *ctx, const u8 *data, unsigned int len) unsigned int partial, done; const u8 *src; - partial = (sctx->count >> 3) & 0x3f; - sctx->count += len << 3; + partial = sctx->count & 0x3f; + sctx->count += len; done = 0; src = data; @@ -88,10 +88,10 @@ static void sha1_final(void* ctx, u8 *out) __be64 bits; static const u8 padding[64] = { 0x80, }; - bits = cpu_to_be64(sctx->count); + bits = cpu_to_be64(sctx->count << 3); /* Pad out to 56 mod 64 */ - index = (sctx->count >> 3) & 0x3f; + index = sctx->count & 0x3f; padlen = (index < 56) ? (56 - index) : ((64+56) - index); sha1_update(sctx, padding, padlen); -- 2.20.1