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author | Matthias P. Braendli <matthias.braendli@mpb.li> | 2014-01-02 21:55:13 +0100 |
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committer | Matthias P. Braendli <matthias.braendli@mpb.li> | 2014-01-02 21:55:13 +0100 |
commit | a31630e0d5b9880c716d9004ef4154396ba41ebc (patch) | |
tree | aebbd3b132e5f2dd31bc34750ccded2378fc687a /fec.c | |
parent | 9aaac5be9db5e1537badc65242412ef14c5096e3 (diff) | |
download | ka9q-fec-a31630e0d5b9880c716d9004ef4154396ba41ebc.tar.gz ka9q-fec-a31630e0d5b9880c716d9004ef4154396ba41ebc.tar.bz2 ka9q-fec-a31630e0d5b9880c716d9004ef4154396ba41ebc.zip |
Extract fec-3.0.1
Diffstat (limited to 'fec.c')
-rw-r--r-- | fec.c | 66 |
1 files changed, 66 insertions, 0 deletions
@@ -0,0 +1,66 @@ +/* Utility routines for FEC support + * Copyright 2004, Phil Karn, KA9Q + */ + +#include <stdio.h> +#include "fec.h" + +unsigned char Partab[256]; +int P_init; + +/* Create 256-entry odd-parity lookup table + * Needed only on non-ia32 machines + */ +void partab_init(void){ + int i,cnt,ti; + + /* Initialize parity lookup table */ + for(i=0;i<256;i++){ + cnt = 0; + ti = i; + while(ti){ + if(ti & 1) + cnt++; + ti >>= 1; + } + Partab[i] = cnt & 1; + } + P_init=1; +} + +/* Lookup table giving count of 1 bits for integers 0-255 */ +int Bitcnt[] = { + 0, 1, 1, 2, 1, 2, 2, 3, + 1, 2, 2, 3, 2, 3, 3, 4, + 1, 2, 2, 3, 2, 3, 3, 4, + 2, 3, 3, 4, 3, 4, 4, 5, + 1, 2, 2, 3, 2, 3, 3, 4, + 2, 3, 3, 4, 3, 4, 4, 5, + 2, 3, 3, 4, 3, 4, 4, 5, + 3, 4, 4, 5, 4, 5, 5, 6, + 1, 2, 2, 3, 2, 3, 3, 4, + 2, 3, 3, 4, 3, 4, 4, 5, + 2, 3, 3, 4, 3, 4, 4, 5, + 3, 4, 4, 5, 4, 5, 5, 6, + 2, 3, 3, 4, 3, 4, 4, 5, + 3, 4, 4, 5, 4, 5, 5, 6, + 3, 4, 4, 5, 4, 5, 5, 6, + 4, 5, 5, 6, 5, 6, 6, 7, + 1, 2, 2, 3, 2, 3, 3, 4, + 2, 3, 3, 4, 3, 4, 4, 5, + 2, 3, 3, 4, 3, 4, 4, 5, + 3, 4, 4, 5, 4, 5, 5, 6, + 2, 3, 3, 4, 3, 4, 4, 5, + 3, 4, 4, 5, 4, 5, 5, 6, + 3, 4, 4, 5, 4, 5, 5, 6, + 4, 5, 5, 6, 5, 6, 6, 7, + 2, 3, 3, 4, 3, 4, 4, 5, + 3, 4, 4, 5, 4, 5, 5, 6, + 3, 4, 4, 5, 4, 5, 5, 6, + 4, 5, 5, 6, 5, 6, 6, 7, + 3, 4, 4, 5, 4, 5, 5, 6, + 4, 5, 5, 6, 5, 6, 6, 7, + 4, 5, 5, 6, 5, 6, 6, 7, + 5, 6, 6, 7, 6, 7, 7, 8, +}; + |