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From f334f74575cb0d9463d39caf4a43483cfc3dd542 Mon Sep 17 00:00:00 2001
From: Herbert Xu <herbert@gondor.apana.org.au>
Date: Thu, 26 Jan 2012 15:03:16 +1100
Subject: [PATCH 20/30] crypto: sha512 - Use binary and instead of modulus
commit 58d7d18b5268febb8b1391c6dffc8e2aaa751fcd upstream.
The previous patch used the modulus operator over a power of 2
unnecessarily which may produce suboptimal binary code. This
patch changes changes them to binary ands instead.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
crypto/sha512_generic.c | 4 ++--
1 files changed, 2 insertions(+), 2 deletions(-)
diff --git a/crypto/sha512_generic.c b/crypto/sha512_generic.c
index 88f160b..3edebfd 100644
--- a/crypto/sha512_generic.c
+++ b/crypto/sha512_generic.c
@@ -78,7 +78,7 @@ static inline void LOAD_OP(int I, u64 *W, const u8 *input)
static inline void BLEND_OP(int I, u64 *W)
{
- W[I % 16] += s1(W[(I-2) % 16]) + W[(I-7) % 16] + s0(W[(I-15) % 16]);
+ W[I & 15] += s1(W[(I-2) & 15]) + W[(I-7) & 15] + s0(W[(I-15) & 15]);
}
static void
@@ -105,7 +105,7 @@ sha512_transform(u64 *state, const u8 *input)
#define SHA512_16_79(i, a, b, c, d, e, f, g, h) \
BLEND_OP(i, W); \
- t1 = h + e1(e) + Ch(e, f, g) + sha512_K[i] + W[(i)%16]; \
+ t1 = h + e1(e) + Ch(e, f, g) + sha512_K[i] + W[(i)&15]; \
t2 = e0(a) + Maj(a, b, c); \
d += t1; \
h = t1 + t2
--
1.7.7.4
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