From: bg <bg@b1d182e4-1ff8-0310-901f-bddb46175740>
Date: Tue, 28 Apr 2009 20:11:12 +0000 (+0000)
Subject: small speedup
X-Git-Url: https://git.cryptolib.org/?a=commitdiff_plain;h=58cf280bb781151e2cd91efd22d5ce9696b3aa62;p=avr-crypto-lib.git

small speedup
---

diff --git a/bmw_small.c b/bmw_small.c
index 2698700..e1ddeff 100644
--- a/bmw_small.c
+++ b/bmw_small.c
@@ -27,8 +27,10 @@
 
 #include <stdint.h>
 #include <string.h>
+#include <avr/pgmspace.h>
 #include "bmw_small.h"
 
+
 #define SHL32(a,n) ((a)<<(n))
 #define SHR32(a,n) ((a)>>(n))
 #define ROTL32(a,n) (((a)<<(n))|((a)>>(32-(n))))
@@ -164,11 +166,18 @@ uint32_t bmw_small_r7(uint32_t x){
 	return r;	
 }
 
+#define K 0x05555555L
+uint32_t k_lut[] PROGMEM = {
+	16L*K, 17L*K, 18L*K, 19L*K, 20L*K, 21L*K, 22L*K, 23L*K,
+	24L*K, 25L*K, 26L*K, 27L*K, 28L*K, 29L*K, 30L*K, 31L*K
+};
+
 uint32_t bmw_small_expand1(uint8_t j, const uint32_t* q, const void* m){
 	uint32_t(*s[])(uint32_t) = {bmw_small_s1, bmw_small_s2, bmw_small_s3, bmw_small_s0};
 	uint32_t r;
 	uint8_t i;
-	r = 0x05555555*(j+16);
+	/* r = 0x05555555*(j+16); */
+	r = pgm_read_dword(k_lut+j);
 	for(i=0; i<16; ++i){
 		r += s[i%4](q[j+i]);
 	}
@@ -184,7 +193,8 @@ uint32_t bmw_small_expand2(uint8_t j, const uint32_t* q, const void* m){
 							     bmw_small_r7};
 	uint32_t r;
 	uint8_t i;
-	r = 0x05555555*(j+16);
+	/* r = 0x05555555*(j+16); */
+	r = pgm_read_dword(k_lut+j);
 	for(i=0; i<14; i+=2){
 		r += q[j+i];
 	}