From cc26d167f796adaa33ca3cbec8016f7915b6033b Mon Sep 17 00:00:00 2001
From: bg <daniel.otte@rub.de>
Date: Tue, 18 Dec 2012 23:04:45 +0100
Subject: [PATCH] progress in asm version of keccak (theta now in asm)

---
 keccak/keccak-asm.S  | 117 ++++++++++++++++++++++++++++++++-----------
 keccak/keccak-stub.c |  15 +-----
 2 files changed, 89 insertions(+), 43 deletions(-)

diff --git a/keccak/keccak-asm.S b/keccak/keccak-asm.S
index 3284763..9ccd79e 100644
--- a/keccak/keccak-asm.S
+++ b/keccak/keccak-asm.S
@@ -28,6 +28,8 @@
 .nolist
 #include "avr-asm-macros.S"
 .list
+
+.equ __zero_reg__, 1
 /*
 	void keccak_theta (uint64_t *a, uint64_t *b){
 	// uint64_t b[5][5];
@@ -37,8 +39,9 @@
   	}
 */
 
-theta_2a:
-/*
+/*********************************************
+ * theta_2a
+ *********************************************
 	input:
 		r24:r25 = a ; uint64_t a[5][5]
 		X = b       ; uint64_t *b
@@ -51,6 +54,7 @@ theta_2a:
 		X += 8
 		Z = r24:r25 + 7 + 4 * 40
 */
+theta_2a:
 	ldi r20, 8
 10:
 	movw ZL, r24
@@ -68,6 +72,60 @@ theta_2a:
 	brne 10b
 	ret
 
+/*********************************************
+ * theta_2b
+ *********************************************
+	input:
+		r24:r25 = a+1 ; uint64_t a[5][5]
+		X = b       ; uint64_t *b
+	output:
+		a[0..4][0] ^= rol(b,1)
+		r19 = XX
+		r20 = 0
+		r21 = XX
+		r22 = XX
+		r24:r25 += 8
+		X += 8
+		Z = r24:r25 + 7 + 4 * 40
+*/
+theta_2b:
+	ldi r20, 7
+	ld r19, X+
+	lsl r19
+	rol __zero_reg__
+10:
+	movw ZL, r24
+	ld  r21, X+
+	ror __zero_reg__
+	rol r21
+	rol __zero_reg__
+	.irp r, 0, 1, 2, 3, 4
+		ld  r22, Z
+		eor r22, r21
+		st  Z, r22
+	.if \r != 4
+		adiw ZL, 40
+	.endif
+	.endr
+	adiw r24, 1
+	dec r20
+	brne 10b
+	add r19, __zero_reg__
+	sbiw r24, 8
+	movw ZL, r24
+	.irp r, 0, 1, 2, 3, 4
+		ld  r22, Z
+		eor r22, r19
+		st  Z, r22
+	.if \r != 4
+		adiw ZL, 40
+	.endif
+	.endr
+	adiw r24, 9
+	clr __zero_reg__
+	ret
+
+
 .global keccak_theta
 keccak_theta:
 	movw r30, r24 ; Z = a
@@ -104,17 +162,11 @@ keccak_theta:
 			a[j][i] ^= b[(4 + i) % 5][0];
 		}
 	}
-	for(i = 0; i < 5; ++i){
-        for(j = 0; j < 5; ++j){
-            a[j][i] ^= rotate64_1bit_left(b[(i + 1) % 5][0]);
-        }
-    }
 
 */
-	sbiw XL, 5 * 8
-
-	sbiw r24, 40
 /* a[0..4][0]{0..7} ^= b[4][0]{0..7} */
+	sbiw XL, 5 * 8
+	sbiw r24, 40
 	rcall theta_2a
 /* a[0..4][1]{0..7} ^= b[0][0]{0..7} */
 	subi XL, lo8(4 * 5 * 8 + 8)
@@ -129,25 +181,32 @@ keccak_theta:
 /* a[0..4][4]{0..7} ^= b[3][0]{0..7} */
 	adiw XL, 4 * 8
 	rcall theta_2a
-
-	ret
-
-	ldi r20, 8
-
-10:
-	movw ZL, r24
-	ld  r21, X+
-	.irp r, 0, 1, 2, 3, 4
-		ld  r22, Z
-		eor r22, r21
-		st  Z, r22
-	.if \r != 4
-		adiw ZL, 40
-	.endif
-	.endr
-	adiw r24, 1
-	dec r20
-	brne 10b
+/*
+	for(i = 0; i < 5; ++i){
+        for(j = 0; j < 5; ++j){
+            a[j][i] ^= rotate64_1bit_left(b[(i + 1) % 5][0]);
+        }
+    }
+*/
+/* a[0..4][0]{0..7} ^= rol(b[1][0]{0..7}) */
+	subi r24, lo8(5 * 8 - 1)
+	sbci r25, hi8(5 * 8 - 1)
+	subi XL, lo8(2 * 5 * 8 + 8)
+	sbci XH, hi8(2 * 5 * 8 + 8)
+	rcall theta_2b
+/* a[0..4][1]{0..7} ^= rol(b[2][0]{0..7}) */
+	adiw XL, 4 * 8
+	rcall theta_2b
+/* a[0..4][21]{0..7} ^= rol(b[3][0]{0..7}) */
+	adiw XL, 4 * 8
+	rcall theta_2b
+/* a[0..4][3]{0..7} ^= rol(b[4][0]{0..7}) */
+	adiw XL, 4 * 8
+	rcall theta_2b
+/* a[0..4][4]{0..7} ^= rol(b[0][0]{0..7}) */
+	subi XL, lo8(4 * 5 * 8 + 8)
+	sbci XH, hi8(4 * 5 * 8 + 8)
+	rcall theta_2b
 
 
 	ret
diff --git a/keccak/keccak-stub.c b/keccak/keccak-stub.c
index 60cf2d1..d1eb501 100644
--- a/keccak/keccak-stub.c
+++ b/keccak/keccak-stub.c
@@ -30,7 +30,7 @@
 #  undef DEBUG
 #endif
 
-#define DEBUG 1
+#define DEBUG 0
 
 #if DEBUG
 #include "cli.h"
@@ -107,20 +107,7 @@ void keccak_round(uint64_t a[5][5], uint8_t rci){
 			uint8_t v8[8];
 		} t;
 	/* theta */
-#if DEBUG & 0
-    printf_P(PSTR("\npre-theta(1):"));
-    keccak_dump_state(b);
-#endif
 	keccak_theta((uint64_t*)a, (uint64_t*)b);
-#if DEBUG
-    printf_P(PSTR("\npost-theta(1):"));
-	keccak_dump_state(b);
-#endif
-	for(i = 0; i < 5; ++i){
-        for(j = 0; j < 5; ++j){
-            a[j][i] ^= rotate64_1bit_left(b[(i + 1) % 5][0]);
-        }
-    }
 #if DEBUG
 	cli_putstr_P(PSTR("\r\nAfter theta:"));
 	keccak_dump_state(a);