Réécriture de M_R³ en Python

1 files changed, 15 insertions, 57 deletions

diff --git a/src/add_python/lilliput/multiplications.py b/src/add_python/lilliput/multiplications.py
index edbdaf3..a5faa55 100644
--- a/src/add_python/lilliput/multiplications.py
+++ b/src/add_python/lilliput/multiplications.py
@@ -44,6 +44,9 @@ def _M2(xi):
 def _M3(xi):
     return xi & 0b00011111
 
+def _M4(xi):
+    return ((xi<<2) & 0xff) >> 3
+
 
 M = (
     ( _0,    _Id,     _0,     _0,  _0,  _0,  _0,  _0),
@@ -78,7 +81,6 @@ M3 = (
     ( _0,     _0,    _Id,     _0,     _0,     _0,  _0,  _0),
 )
 
-
 # NB: shift directions are reversed with respect to the specification
 # for powers of M_R, since the specification reverses the byte order
 # for those matrices.
@@ -105,6 +107,17 @@ MR2 = (
     ( _0, _Id,  _0,     _0,     _0,     _0,     _0,     _0),
 )
 
+MR3 = (
+    (    _0,  _0,  _0,    _Id, _Sr(3),     _0,     _0,     _0),
+    (    _0,  _0,  _0,     _0,    _Id, _Sr(3),    _M3,     _0),
+    (    _0,  _0,  _0,    _M4,     _0,    _Id,    _M1,    _M3),
+    (    _0,  _0,  _0, _Sl(2),     _0,     _0,    _Id, _Sl(3)),
+    (_Sl(3),  _0,  _0,     _0, _Sl(2),     _0,     _0,    _Id),
+    (   _Id,  _0,  _0,     _0,     _0, _Sl(2), _Sl(5),     _0),
+    (    _0, _Id,  _0,     _0,     _0,     _0,     _0,     _0),
+    (    _0,  _0, _Id,     _0,     _0,     _0,     _0,     _0),
+)
+
 
 def _multiplication(m, reverse=True):
     def ordered(l):
@@ -121,61 +134,6 @@ def _multiplication(m, reverse=True):
     return _multiply
 
 
-def _multiply_MR3(lane):
-    multiplied_lane = [lane[(byte+3) % 8] for byte in range(0, 8)]
-
-    multiplied_lane[0] ^= ((lane[4] >> 3) & 0xff)
-    multiplied_lane[1] ^= ((lane[5] >> 3) & 0xff)
-    multiplied_lane[3] ^= ((lane[3] << 2) & 0xff) ^ ((lane[7] << 3) & 0xff)
-    multiplied_lane[4] ^= ((lane[0] << 3) & 0xff) ^ ((lane[4] << 2) & 0xff)
-    multiplied_lane[5] ^= ((lane[5] << 2) & 0xff) ^ ((lane[6] << 5) & 0xff)
-
-    # binary matrix m3
-    multi_mat_l6_m3 = 0
-    l6 = lane[6]
-    multi_mat_l6_m3 ^= (l6 & 0x1)
-    multi_mat_l6_m3 ^= (l6 & 0x2)
-    multi_mat_l6_m3 ^= (l6 & 0x4)
-    multi_mat_l6_m3 ^= (l6 & 0x8)
-    multi_mat_l6_m3 ^= (l6 & 0x10)
-
-    # binary matrix m3
-    multi_mat_l7_m3 = 0
-    l7 = lane[7]
-    multi_mat_l7_m3 ^= (l7 & 0x1)
-    multi_mat_l7_m3 ^= (l7 & 0x2)
-    multi_mat_l7_m3 ^= (l7 & 0x4)
-    multi_mat_l7_m3 ^= (l7 & 0x8)
-    multi_mat_l7_m3 ^= (l7 & 0x10)
-
-    # binary matrix m4
-    multi_mat_l3_m4 = 0
-    l3 = lane[3]
-    multi_mat_l3_m4 ^= ((l3 & 0x2) >> 1)
-    multi_mat_l3_m4 ^= ((l3 & 0x4) >> 1)
-    multi_mat_l3_m4 ^= ((l3 & 0x8) >> 1)
-    multi_mat_l3_m4 ^= ((l3 & 0x10) >> 1)
-    multi_mat_l3_m4 ^= ((l3 & 0x20) >> 1)
-
-    # binary matrix m1 for MR
-    multi_mat_l6_m1 = 0
-    l6 = lane[6]
-    multi_mat_l6_m1 ^= ((l6 & 0x8) >> 3)
-    multi_mat_l6_m1 ^= ((l6 & 0x10) >> 3)
-    multi_mat_l6_m1 ^= ((l6 & 0x20) >> 3)
-    multi_mat_l6_m1 ^= ((l6 & 0x40) >> 3) ^ ((l6 & 0x1) << 3)
-    multi_mat_l6_m1 ^= ((l6 & 0x80) >> 3) ^ ((l6 & 0x2) << 3)
-    multi_mat_l6_m1 ^= ((l6 & 0x4) << 3)
-    multi_mat_l6_m1 ^= ((l6 & 0x8) << 3)
-    multi_mat_l6_m1 ^= ((l6 & 0x10) << 3)
-
-
-    multiplied_lane[1] ^= multi_mat_l6_m3
-    multiplied_lane[2] ^= multi_mat_l3_m4 ^ multi_mat_l6_m1 ^ multi_mat_l7_m3
-
-    return multiplied_lane
-
-
 ALPHAS = (
     list,                       # Identity.
     _multiplication(M),
@@ -183,5 +141,5 @@ ALPHAS = (
     _multiplication(M3),
     _multiplication(MR, reverse=False),
     _multiplication(MR2, reverse=False),
-    _multiply_MR3
+    _multiplication(MR3, reverse=False)
 )