From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Message-Id: <20120217005536.766801087@linuxfoundation.org> Date: Thu, 16 Feb 2012 16:55:54 -0800 From: Greg KH To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: torvalds@linux-foundation.org, akpm@linux-foundation.org, alan@lxorguk.ukuu.org.uk, Herbert Xu Subject: [20/28] crypto: sha512 - Use binary and instead of modulus In-Reply-To: <20120217005609.GA17081@kroah.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: 3.2-stable review patch. If anyone has any objections, please let me know. ------------------ From: Herbert Xu 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 Signed-off-by: Greg Kroah-Hartman --- crypto/sha512_generic.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) --- a/crypto/sha512_generic.c +++ b/crypto/sha512_generic.c @@ -78,7 +78,7 @@ static inline void LOAD_OP(int I, u64 *W 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 *i #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