Update hamming.txt with information for our (31,26) code.

diff --git a/hamming.txt b/hamming.txt
index aa9e9471206fd584c816f340d451289ce75e1d13..1bd50d425e9635940c3d17f384cec2f7110c19f0 100644 (file)
--- a/hamming.txt
+++ b/hamming.txt
@@ -26,3 +26,31 @@ Strategy: lookup tables. Table of 2048 values -> 5 parity bits should be very
          cheap (consume 2kB of RAM for unsigned char, fits nicely into L1
           cache and all). Do we want to encode extra information here? Probably
           not worth it at all...
+
+Expansion to (31,26):
+
+ 1  2  3  4  5  6  7  8  9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31
+p1 p2 D1 p1 D2 D3 D4 p4 D5 D6 D7 D8 D9 DA DB p5 DC DD DE DF DG DH DI DJ DK DL DM DN DO DP DQ
+--    xx    xx    xx    xx    xx    xx    xx    xx    xx    xx    xx    xx    xx    xx    xx
+   -- xx       xx xx       xx xx       xx xx       xx xx       xx xx       xx xx       xx xx
+         -- xx xx xx             xx xx xx xx             xx xx xx xx             xx xx xx xx
+                     -- xx xx xx xx xx xx xx                         xx xx xx xx xx xx xx xx
+                                             -- xx xx xx xx xx xx xx xx xx xx xx xx xx xx xx
+
+Reordering:
+
+   D1 D2  D3 D4 D5 D6 D7 D8 D9 DA  DB DC DD DE DF DG DH DI  DJ DK DL DM DN DO DP DQ
+p1 xx xx     xx xx    xx    xx     xx xx    xx    xx    xx     xx    xx    xx    xx
+p2 xx     xx xx    xx xx       xx  xx    xx xx       xx xx        xx xx       xx xx
+p3    xx  xx xx          xx xx xx  xx          xx xx xx xx              xx xx xx xx
+p4              xx xx xx xx xx xx  xx                       xx xx xx xx xx xx xx xx
+p5                                    xx xx xx xx xx xx xx  xx xx xx xx xx xx xx xx
+
+
+Converted to bitmasks:
+
+p1: 03 6a d5 55
+p2: 02 d9 b3 33
+p3: 01 c7 8f 0f
+p4: 00 3f 80 ff
+p5: 00 00 7f ff