[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>
diff --git a/crypto/sha1.c b/crypto/sha1.c
index 7b1abca..8048e2d 100644
--- a/crypto/sha1.c
+++ b/crypto/sha1.c
@@ -52,8 +52,8 @@
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 @@
__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);