[PATCH] camellia: simplify key setup and CAMELLIA_ROUNDSM macro

[PATCH] camellia: simplify key setup and CAMELLIA_ROUNDSM macro

[Jussi Kivilinna]

camellia_setup_tail() applies 'inverse of the last half of P-function' to
subkeys, which is unneeded if keys are applied directly to yl/yr in
CAMELLIA_ROUNDSM.

Patch speeds up key setup and should speed up CAMELLIA_ROUNDSM as applying
key to yl/yr early has less register dependencies.

Quick tcrypt camellia results:
 x86_64, AMD Phenom II, ~5% faster
 x86_64, Intel Core 2, ~0.5% faster
 i386, Intel Atom N270, ~1% faster

Signed-off-by: Jussi Kivilinna <jussi.kivilinna@mbnet.fi>
---
 crypto/camellia.c |   24 +++---------------------
 1 files changed, 3 insertions(+), 21 deletions(-)

diff --git a/crypto/camellia.c b/crypto/camellia.c
index 64cff46..7ae4bcd 100644
--- a/crypto/camellia.c
+++ b/crypto/camellia.c
@@ -382,7 +382,6 @@ static void camellia_setup_tail(u32 *subkey, u32 *subL, u32 *subR, int max)
 {
 	u32 dw, tl, tr;
 	u32 kw4l, kw4r;
-	int i;
 
 	/* absorb kw2 to other subkeys */
 	/* round 2 */
@@ -557,24 +556,6 @@ static void camellia_setup_tail(u32 *subkey, u32 *subL, u32 *subR, int max)
 		SUBKEY_L(32) = subL[32] ^ subL[31]; /* kw3 */
 		SUBKEY_R(32) = subR[32] ^ subR[31];
 	}
-
-	/* apply the inverse of the last half of P-function */
-	i = 2;
-	do {
-		dw = SUBKEY_L(i + 0) ^ SUBKEY_R(i + 0); dw = rol32(dw, 8);/* round 1 */
-		SUBKEY_R(i + 0) = SUBKEY_L(i + 0) ^ dw; SUBKEY_L(i + 0) = dw;
-		dw = SUBKEY_L(i + 1) ^ SUBKEY_R(i + 1); dw = rol32(dw, 8);/* round 2 */
-		SUBKEY_R(i + 1) = SUBKEY_L(i + 1) ^ dw; SUBKEY_L(i + 1) = dw;
-		dw = SUBKEY_L(i + 2) ^ SUBKEY_R(i + 2); dw = rol32(dw, 8);/* round 3 */
-		SUBKEY_R(i + 2) = SUBKEY_L(i + 2) ^ dw; SUBKEY_L(i + 2) = dw;
-		dw = SUBKEY_L(i + 3) ^ SUBKEY_R(i + 3); dw = rol32(dw, 8);/* round 4 */
-		SUBKEY_R(i + 3) = SUBKEY_L(i + 3) ^ dw; SUBKEY_L(i + 3) = dw;
-		dw = SUBKEY_L(i + 4) ^ SUBKEY_R(i + 4); dw = rol32(dw, 8);/* round 5 */
-		SUBKEY_R(i + 4) = SUBKEY_L(i + 4) ^ dw; SUBKEY_L(i + 4) = dw;
-		dw = SUBKEY_L(i + 5) ^ SUBKEY_R(i + 5); dw = rol32(dw, 8);/* round 6 */
-		SUBKEY_R(i + 5) = SUBKEY_L(i + 5) ^ dw; SUBKEY_L(i + 5) = dw;
-		i += 8;
-	} while (i < max);
 }
 
 static void camellia_setup128(const unsigned char *key, u32 *subkey)
@@ -869,6 +850,8 @@ static void camellia_setup192(const unsigned char *key, u32 *subkey)
 
 #define CAMELLIA_ROUNDSM(xl, xr, kl, kr, yl, yr, il, ir)		\
     do {								\
+	yl ^= kl;							\
+	yr ^= kr;							\
 	ir =  camellia_sp1110[(u8)xr];					\
 	il =  camellia_sp1110[    (xl >> 24)];				\
 	ir ^= camellia_sp0222[    (xr >> 24)];				\
@@ -877,8 +860,7 @@ static void camellia_setup192(const unsigned char *key, u32 *subkey)
 	il ^= camellia_sp3033[(u8)(xl >> 8)];				\
 	ir ^= camellia_sp4404[(u8)(xr >> 8)];				\
 	il ^= camellia_sp4404[(u8)xl];					\
-	il ^= kl;							\
-	ir ^= il ^ kr;							\
+	ir ^= il;							\
 	yl ^= ir;							\
 	yr ^= ror32(il, 8) ^ ir;						\
     } while (0)

Re: [PATCH] camellia: simplify key setup and CAMELLIA_ROUNDSM macro

[Herbert Xu]

On Sat, Mar 03, 2012 at 01:59:00PM +0200, Jussi Kivilinna wrote:
> camellia_setup_tail() applies 'inverse of the last half of P-function' to
> subkeys, which is unneeded if keys are applied directly to yl/yr in
> CAMELLIA_ROUNDSM.
> 
> Patch speeds up key setup and should speed up CAMELLIA_ROUNDSM as applying
> key to yl/yr early has less register dependencies.
> 
> Quick tcrypt camellia results:
>  x86_64, AMD Phenom II, ~5% faster
>  x86_64, Intel Core 2, ~0.5% faster
>  i386, Intel Atom N270, ~1% faster
> 
> Signed-off-by: Jussi Kivilinna <jussi.kivilinna@mbnet.fi>

Patch applied.  Thanks!
-- 
Email: Herbert Xu <herbert@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt