X-Git-Url: https://git.cryptolib.org/?p=avr-crypto-lib.git;a=blobdiff_plain;f=host%2Foptimize_shift.rb;fp=host%2Foptimize_shift.rb;h=e667697a3a2f13abb04ad4b08a19625b8aa34603;hp=0000000000000000000000000000000000000000;hb=f215d8ed649fd5bf5f85eb34f851a1539302013d;hpb=ba4ac1b4a8020026fb6f1a45a1e04e16017262f7

diff --git a/host/optimize_shift.rb b/host/optimize_shift.rb
new file mode 100644
index 0000000..e667697
--- /dev/null
+++ b/host/optimize_shift.rb
@@ -0,0 +1,82 @@
+#!/usr/bin/ruby 
+# shavs_test.rb
+=begin
+    This file is part of the AVR-Crypto-Lib.
+    Copyright (C) 2008  Daniel Otte (daniel.otte@rub.de)
+
+    This program is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+=end
+
+shift_values = [ 5, 36, 13, 58, 26, 53, 11, 59, 
+                56, 28, 46, 44, 20, 35, 42, 50,
+               
+			    38, 48, 34, 26, 33, 39, 29, 33, 
+                30, 20, 14, 12, 49, 27, 26, 51,
+                50, 43, 15, 58,  8, 41, 11, 39,
+                53, 31, 27,  7, 42, 14,  9, 35,
+               
+			    55, 25, 33, 34, 28, 17, 58, 47,
+                43, 25,  8, 43,  7,  6,  7, 49,
+                37, 46, 18, 25, 47, 18, 32, 27,
+                40, 13, 57, 60, 48, 25, 45, 58,
+                16, 14, 21, 44, 51, 43, 19, 37,
+                22, 13, 12,  9,  9, 42, 18, 48,
+                38, 52, 32, 59, 35, 40,  2, 53,
+                12, 57, 54, 34, 41, 15, 56, 56 ]
+
+def transform_shift(value)
+  byteshift = (value+3)/8
+  singleshift = value%8
+  if singleshift>4
+ #   byteshift += 1
+	singleshift -= 8
+  end
+  return [singleshift, byteshift]
+end
+
+def transform_singleshift(value)
+  if(value>=0)
+    return value
+  end
+  return 0x08+(value*-1)
+end
+
+bs_hist = Hash.new
+bs_hist.default = 0
+ss_hist = Hash.new
+ss_hist.default = 0
+shift_values.each{|v|
+  
+  a = transform_shift(v)
+  printf("%2d = %2d * 8 %+2d\n", v, a[1], a[0])
+  bs_hist[a[1]] += 1
+  ss_hist[a[0]] += 1
+}
+
+puts("byteshift histogram:")
+for i in 0..7
+  printf("%d: %4d\n", i, bs_hist[i])
+ end
+
+puts("singleshift histogram:")
+for i in -3..4
+  printf("%+d: %4d\n", i, ss_hist[i])
+ end
+
+(0..shift_values.length-1).each{|i|
+  a = transform_shift(shift_values[i])
+  a[0] = transform_singleshift(a[0])
+  printf("0x%01x%01x, ", a[1], a[0])
+  puts("") if (i%8==7)
+}