From: Denis Vlasenko <vda@ilport.com.ua>
Date: Tue, 29 Nov 2005 11:23:20 +0000 (+1100)
Subject: [CRYPTO] aes-i586: Nano-optimisation on key length check
X-Git-Tag: v2.6.16-rc1~658^2~20
X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=e6a3a925a25ddd2ebd66dbc8d14ebdd3d57ca0c3;p=linux-2.6

[CRYPTO] aes-i586: Nano-optimisation on key length check

Reduce the number of comparisons by one through the use of jb/je.
This patch also corrects the comments regarding the different key
lengths.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
---

diff --git a/arch/i386/crypto/aes-i586-asm.S b/arch/i386/crypto/aes-i586-asm.S
index 7b73c67cb4..911b15377f 100644
--- a/arch/i386/crypto/aes-i586-asm.S
+++ b/arch/i386/crypto/aes-i586-asm.S
@@ -255,18 +255,17 @@ aes_enc_blk:
 	xor     8(%ebp),%r4
 	xor     12(%ebp),%r5
 
-	sub     $8,%esp           // space for register saves on stack
-	add     $16,%ebp          // increment to next round key
-	sub     $10,%r3          
-	je      4f              // 10 rounds for 128-bit key
-	add     $32,%ebp
-	sub     $2,%r3
-	je      3f              // 12 rounds for 128-bit key
-	add     $32,%ebp
-
-2:	fwd_rnd1( -64(%ebp) ,ft_tab)	// 14 rounds for 128-bit key
+	sub     $8,%esp		// space for register saves on stack
+	add     $16,%ebp	// increment to next round key
+	cmp     $12,%r3
+	jb      4f		// 10 rounds for 128-bit key
+	lea     32(%ebp),%ebp
+	je      3f		// 12 rounds for 192-bit key
+	lea     32(%ebp),%ebp
+
+2:	fwd_rnd1( -64(%ebp) ,ft_tab)	// 14 rounds for 256-bit key
 	fwd_rnd2( -48(%ebp) ,ft_tab)
-3:	fwd_rnd1( -32(%ebp) ,ft_tab)	// 12 rounds for 128-bit key
+3:	fwd_rnd1( -32(%ebp) ,ft_tab)	// 12 rounds for 192-bit key
 	fwd_rnd2( -16(%ebp) ,ft_tab)
 4:	fwd_rnd1(    (%ebp) ,ft_tab)	// 10 rounds for 128-bit key
 	fwd_rnd2( +16(%ebp) ,ft_tab)
@@ -334,18 +333,17 @@ aes_dec_blk:
 	xor     8(%ebp),%r4
 	xor     12(%ebp),%r5
 
-	sub     $8,%esp         // space for register saves on stack
-	sub     $16,%ebp        // increment to next round key
-	sub     $10,%r3          
-	je      4f              // 10 rounds for 128-bit key
-	sub     $32,%ebp
-	sub     $2,%r3
-	je      3f              // 12 rounds for 128-bit key
-	sub     $32,%ebp
+	sub     $8,%esp		// space for register saves on stack
+	sub     $16,%ebp	// increment to next round key
+	cmp     $12,%r3
+	jb      4f		// 10 rounds for 128-bit key
+	lea     -32(%ebp),%ebp
+	je      3f		// 12 rounds for 192-bit key
+	lea     -32(%ebp),%ebp
 
-2:	inv_rnd1( +64(%ebp), it_tab)	// 14 rounds for 128-bit key
+2:	inv_rnd1( +64(%ebp), it_tab)	// 14 rounds for 256-bit key
 	inv_rnd2( +48(%ebp), it_tab)
-3:	inv_rnd1( +32(%ebp), it_tab)	// 12 rounds for 128-bit key
+3:	inv_rnd1( +32(%ebp), it_tab)	// 12 rounds for 192-bit key
 	inv_rnd2( +16(%ebp), it_tab)
 4:	inv_rnd1(    (%ebp), it_tab)	// 10 rounds for 128-bit key
 	inv_rnd2( -16(%ebp), it_tab)