lilliput-ae-reference-implementation

commit 7b5ab3aa0c5e8c62b4fc9dcb4fc579efb527a4f0
parent e71424ebdd2a3f8a4d8439beb8a5cb2a64b12149
Author: Kévin Le Gouguec <kevin.legouguec@airbus.com>
Date:   Tue, 21 May 2019 14:22:34 +0200

Dé-duplication de code dans l'implémentation FELICS

Apparemment les différents gcc de  FELICS arrivent encore à comprendre
qu'ils peuvent inligner les multiplications ; c'est quand on passe par
un tableau de pointeurs de fonction qu'ils baissent les bras.

Diffstat:
M
src/add_felicsref/tweakey.c
 | 
43
++++++++++++++-----------------------------

1 file changed, 14 insertions(+), 29 deletions(-)
diff --git a/src/add_felicsref/tweakey.c b/src/add_felicsref/tweakey.c
@@ -70,46 +70,31 @@ void tweakey_state_extract(
 }
 
 
-void tweakey_state_update(uint8_t TK[TWEAKEY_BYTES])
-{
-    /* Skip lane 0, as it is multiplied by the identity matrix. */
+typedef void (*matrix_multiplication)(const uint8_t x[LANE_BYTES], uint8_t y[LANE_BYTES]);
 
-    size_t j;
-    uint8_t *TKj;
+static void _multiply(uint8_t TKj[LANE_BYTES], matrix_multiplication alpha)
+{
     uint8_t TKj_old[LANE_BYTES];
-
-    j = 1;
-    TKj = TK + j*LANE_BYTES;
     memcpy(TKj_old, TKj, LANE_BYTES);
-    _multiply_M(TKj_old, TKj);
+    alpha(TKj_old, TKj);
+}
 
-    j = 2;
-    TKj = TK + j*LANE_BYTES;
-    memcpy(TKj_old, TKj, LANE_BYTES);
-    _multiply_M2(TKj_old, TKj);
+void tweakey_state_update(uint8_t TK[TWEAKEY_BYTES])
+{
+    /* Skip lane 0, as it is multiplied by the identity matrix. */
 
-    j = 3;
-    TKj = TK + j*LANE_BYTES;
-    memcpy(TKj_old, TKj, LANE_BYTES);
-    _multiply_M3(TKj_old, TKj);
+    _multiply(TK + 1*LANE_BYTES, _multiply_M);
+    _multiply(TK + 2*LANE_BYTES, _multiply_M2);
+    _multiply(TK + 3*LANE_BYTES, _multiply_M3);
 
 #if LANES_NB >= 5
-    j = 4;
-    TKj = TK + j*LANE_BYTES;
-    memcpy(TKj_old, TKj, LANE_BYTES);
-    _multiply_MR(TKj_old, TKj);
+    _multiply(TK + 4*LANE_BYTES, _multiply_MR);
 
 #if LANES_NB >= 6
-    j = 5;
-    TKj = TK + j*LANE_BYTES;
-    memcpy(TKj_old, TKj, LANE_BYTES);
-    _multiply_MR2(TKj_old, TKj);
+    _multiply(TK + 5*LANE_BYTES, _multiply_MR2);
 
 #if LANES_NB >= 7
-    j = 6;
-    TKj = TK + j*LANE_BYTES;
-    memcpy(TKj_old, TKj, LANE_BYTES);
-    _multiply_MR3(TKj_old, TKj);
+    _multiply(TK + 6*LANE_BYTES, _multiply_MR3);
 #endif
 #endif
 #endif