Make the code look more like the original pseudo code

Also consistently use "int" for the loop variable.  It's always signed
so there's no need to specify that explicitly, and there's simply no
reason to use "uint32".

Author: johto

speck.c

@@ -17,14 +17,15 @@ static void speck_key_expand48(const int64 *K, uint32 *k);
 static void
 speck_key_expand32(const int64 K, uint16 *k)
 {
+	const int rounds = 22;
 	int i;
 	uint16 l[24];
 
 	l[2] = (K & 0xFFFF000000000000) >> 48;
 	l[1] = (K & 0x0000FFFF00000000) >> 32;
 	l[0] = (K & 0x00000000FFFF0000) >> 16;
 
-	for (i = 0; i < 22-1; ++i)
+	for (i = 0; i <= rounds - 2; ++i)
 	{
 		l[i+3] = ((uint16) (k[i] + ROR16(l[i], 7))) ^ i;
 		k[i+1] = (ROL16(k[i], 2) ^ l[i+3]);
@@ -34,14 +35,15 @@ speck_key_expand32(const int64 K, uint16 *k)
 uint32
 speck_encrypt32(const uint32 xy, const int64 K)
 {
-	uint32 i;
+	const int rounds = 22;
+	int i;
 	uint16 k[22];
 	uint16 x = (xy & 0xFFFF0000) >> 16, y = (xy & 0xFFFF);
 
 	k[0] = (K & 0xFFFF);
 	speck_key_expand32(K, k);
 
-	for (i = 0; i < 22; i++)
+	for (i = 0; i <= rounds - 1; i++)
 	{
 		x = (uint16) (ROR16(x, 7) + y);
 		x ^= k[i];
@@ -53,14 +55,15 @@ speck_encrypt32(const uint32 xy, const int64 K)
 uint32
 speck_decrypt32(const uint32 xy, const int64 K)
 {
-	signed int i;
+	const int rounds = 22;
+	int i;
 	uint16 k[22];
 	uint16 x = (xy & 0xFFFF0000) >> 16, y = (xy & 0xFFFF);
 
 	k[0] = (K & 0xFFFF);
 	speck_key_expand32(K, k);
 
-	for (i = 21; i >= 0; i--)
+	for (i = rounds - 1; i >= 0; i--)
 	{
 		y ^= x;
 		y = ROR16(y, 2);
@@ -73,14 +76,15 @@ speck_decrypt32(const uint32 xy, const int64 K)
 static void
 speck_key_expand48(const int64 *K, uint32 *k)
 {
+	const int rounds = 23;
 	int i;
 	uint32 l[25];
 
 	l[2] = (K[0] & 0xFFFFFF000000) >> 24;
 	l[1] = (K[0] & 0x000000FFFFFF) >> 0;
 	l[0] = (K[1] & 0xFFFFFF000000) >> 24;
 
-	for (i = 0; i < 23-1; ++i)
+	for (i = 0; i <= rounds - 2; ++i)
 	{
 		l[i+3] = ((k[i] + ROR24(l[i], 8)) & 0xFFFFFF) ^ i;
 		k[i+1] = (ROL24(k[i], 3) ^ l[i+3]);
@@ -90,14 +94,15 @@ speck_key_expand48(const int64 *K, uint32 *k)
 int64
 speck_encrypt48(const int64 xy, const int64 *K)
 {
+	const int rounds = 23;
 	int i;
 	uint32 k[23];
 	uint32 x = (xy & 0xFFFFFF000000) >> 24, y = (xy & 0xFFFFFF);
 
 	k[0] = (K[1] & 0xFFFFFF);
 	speck_key_expand48(K, k);
 
-	for (i = 0; i < 23; i++)
+	for (i = 0; i <= rounds - 1; i++)
 	{
 		x = ((ROR24(x, 8) + y) & 0xFFFFFF);
 		x ^= k[i];
@@ -109,14 +114,15 @@ speck_encrypt48(const int64 xy, const int64 *K)
 int64
 speck_decrypt48(const int64 xy, const int64 *K)
 {
-	signed int i;
+	const int rounds = 23;
+	int i;
 	uint32 k[23];
 	uint32 x = (xy & 0xFFFFFF000000) >> 24, y = (xy & 0xFFFFFF);
 
 	k[0] = (K[1] & 0xFFFFFF);
 	speck_key_expand48(K, k);
 
-	for (i = 22; i >= 0; i--)
+	for (i = rounds - 1; i >= 0; i--)
 	{
 		y ^= x;
 		y = ROR24(y, 3);