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[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 <nico@cam.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
This commit is contained in:
Nicolas Pitre 2005-11-13 11:17:33 +11:00 committed by David S. Miller
parent 9d70a6c86c
commit fa9b98fdab
1 changed files with 4 additions and 4 deletions
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8
crypto/sha1.c
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@ -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);