From 902ec9e896b4fc442b5d82f4330c7daad8aa7d7a Mon Sep 17 00:00:00 2001
From: Andrew Ekstedt <andrew.ekstedt@gmail.com>
Date: Sat, 3 Jan 2015 01:40:42 -0800
Subject: [PATCH] gen: Alter mod function. Purely cosmetic.

---
 gen.go        | 13 +++++++------
 keccak_gen.go | 20 +++++++++++++++++++-
 2 files changed, 26 insertions(+), 7 deletions(-)

diff --git a/gen.go b/gen.go
index 875e272..025ee5c 100644
--- a/gen.go
+++ b/gen.go
@@ -45,7 +45,7 @@ func count(n int) []int {
 func add(a, b int) int { return a + b }
 func sub(a, b int) int { return a - b }
 func mul(a, b int) int { return a * b }
-func mod(a, b int) int { return a % b }
+func mod(a int) int    { return a % 5 }
 
 func afunc(x, y int) string {
 	return fmt.Sprintf("a[%d]", y%5*5+x%5)
@@ -89,16 +89,16 @@ func roundGo(a *[25]uint64) {
 	{{ end }}
 	var d uint64
 	{{ range $x := count 5 }}
-		{{ $x4 := mod (add $x 4) 5 }}
-		{{ $x1 := mod (add $x 1) 5 }}
+		{{ $x4 := add $x 4 | mod }}
+		{{ $x1 := add $x 1 | mod }}
 		d = c{{$x4}} ^ (c{{$x1}}<<1 | c{{$x1}}>>63)
 		{{ range $y := count 5 }}
 			{{b $x $y}} = {{a $x $y}} ^ d
 		{{ end }}
 	{{ end }}
 
-	// Rho / Pi / Chi / output
 	{{ range $y := count 5 }}
+		// Rho / Pi
 		{{ range $x := count 5 }}
 			{{ $x0 := add $x (mul $y 3) }}
 			{{ $y0 := $x }}
@@ -106,9 +106,10 @@ func roundGo(a *[25]uint64) {
 			{{ $r := rotc $x0 $y0 }}
 			c{{$x}} = {{$b}}<<{{$r}} | {{$b}}>>{{sub 64 $r}}
 		{{ end }}
+		// Chi
 		{{ range $x := count 5 }}
-			{{ $x1 := mod (add $x 1) 5 }}
-			{{ $x2 := mod (add $x 2) 5 }}
+			{{ $x1 := add $x 1 | mod }}
+			{{ $x2 := add $x 2 | mod }}
 			{{a $x $y}} = c{{$x}} ^ (c{{$x2}} &^ c{{$x1}})
 		{{ end }}
 	{{ end }}
diff --git a/keccak_gen.go b/keccak_gen.go
index 8e38058..9d6140b 100644
--- a/keccak_gen.go
+++ b/keccak_gen.go
@@ -91,7 +91,7 @@ func roundGo(a *[25]uint64) {
 
 	b44 = a[24] ^ d
 
-	// Rho / Pi / Chi / output
+	// Rho / Pi
 
 	c0 = b00<<0 | b00>>64
 
@@ -103,6 +103,8 @@ func roundGo(a *[25]uint64) {
 
 	c4 = b44<<14 | b44>>50
 
+	// Chi
+
 	a[0] = c0 ^ (c2 &^ c1)
 
 	a[1] = c1 ^ (c3 &^ c2)
@@ -113,6 +115,8 @@ func roundGo(a *[25]uint64) {
 
 	a[4] = c4 ^ (c1 &^ c0)
 
+	// Rho / Pi
+
 	c0 = b30<<28 | b30>>36
 
 	c1 = b41<<20 | b41>>44
@@ -123,6 +127,8 @@ func roundGo(a *[25]uint64) {
 
 	c4 = b24<<61 | b24>>3
 
+	// Chi
+
 	a[5] = c0 ^ (c2 &^ c1)
 
 	a[6] = c1 ^ (c3 &^ c2)
@@ -133,6 +139,8 @@ func roundGo(a *[25]uint64) {
 
 	a[9] = c4 ^ (c1 &^ c0)
 
+	// Rho / Pi
+
 	c0 = b10<<1 | b10>>63
 
 	c1 = b21<<6 | b21>>58
@@ -143,6 +151,8 @@ func roundGo(a *[25]uint64) {
 
 	c4 = b04<<18 | b04>>46
 
+	// Chi
+
 	a[10] = c0 ^ (c2 &^ c1)
 
 	a[11] = c1 ^ (c3 &^ c2)
@@ -153,6 +163,8 @@ func roundGo(a *[25]uint64) {
 
 	a[14] = c4 ^ (c1 &^ c0)
 
+	// Rho / Pi
+
 	c0 = b40<<27 | b40>>37
 
 	c1 = b01<<36 | b01>>28
@@ -163,6 +175,8 @@ func roundGo(a *[25]uint64) {
 
 	c4 = b34<<56 | b34>>8
 
+	// Chi
+
 	a[15] = c0 ^ (c2 &^ c1)
 
 	a[16] = c1 ^ (c3 &^ c2)
@@ -173,6 +187,8 @@ func roundGo(a *[25]uint64) {
 
 	a[19] = c4 ^ (c1 &^ c0)
 
+	// Rho / Pi
+
 	c0 = b20<<62 | b20>>2
 
 	c1 = b31<<55 | b31>>9
@@ -183,6 +199,8 @@ func roundGo(a *[25]uint64) {
 
 	c4 = b14<<2 | b14>>62
 
+	// Chi
+
 	a[20] = c0 ^ (c2 &^ c1)
 
 	a[21] = c1 ^ (c3 &^ c2)