arm/v6: Alignment tweaks to aes code.

ChangeLog

+2013-05-16  Niels Möller  <nisse@lysator.liu.se>
+
+	* arm/v6/aes-encrypt-internal.asm: Use ALIGN macro. Use 16-byte
+	alignment for loops.
+	* arm/v6/aes-decrypt-internal.asm: Likewise. Also added a nop
+	which mysteriously improves benchmark performance on Cortex-A9.
+
 2013-05-15  Niels Möller  <nisse@lysator.liu.se>
 
 	* configure.ac (asm_path): Handle armv6 and armv7 differently from

arm/v6/aes-decrypt-internal.asm

@@ -50,13 +50,16 @@ define(<X3>, <r14>)	C lr
 	C	       size_t length, uint8_t *dst,
 	C	       uint8_t *src)
 	.text
-	.align 2
+	ALIGN(4)
 PROLOGUE(_nettle_aes_decrypt)
 	teq	LENGTH, #0
 	beq	.Lend
 	ldr	SRC, [sp]
 
 	push	{r4,r5,r6,r7,r8,r10,r11,lr}
+	nop	C For some mysterious reason, taking out this nop
+		C slows this function down on Cortex-A9.
+	ALIGN(16)
 .Lblock_loop:
 	mov	KEY, CTX
 	AES_LOAD(SRC,KEY,W0)
@@ -69,7 +72,7 @@ PROLOGUE(_nettle_aes_decrypt)
 	add	TABLE, TABLE, #AES_TABLE0
 
 	b	.Lentry
-	.align 2
+	ALIGN(16)
 .Lround_loop:
 	C	Transform X -> W
 	AES_DECRYPT_ROUND(X0, X1, X2, X3, W0, W1, W2, W3, KEY)

arm/v6/aes-encrypt-internal.asm

@@ -52,13 +52,14 @@ define(<X3>, <r14>)	C lr
 	C	       size_t length, uint8_t *dst,
 	C	       uint8_t *src)
 	.text
-	.align 2
+	ALIGN(4)
 PROLOGUE(_nettle_aes_encrypt)
 	teq	LENGTH, #0
 	beq	.Lend
 	ldr	SRC, [sp]
 
 	push	{r4,r5,r6,r7,r8,r10,r11,lr}
+	ALIGN(16)
 .Lblock_loop:
 	mov	KEY, CTX
 	AES_LOAD(SRC,KEY,W0)
@@ -71,7 +72,7 @@ PROLOGUE(_nettle_aes_encrypt)
 	add	TABLE, TABLE, #AES_TABLE0
 
 	b	.Lentry
-	.align 2
+	ALIGN(16)
 .Lround_loop:
 	C	Transform X -> W
 	AES_ENCRYPT_ROUND(X0, X1, X2, X3, W0, W1, W2, W3, KEY)