From a31630e0d5b9880c716d9004ef4154396ba41ebc Mon Sep 17 00:00:00 2001 From: "Matthias P. Braendli" Date: Thu, 2 Jan 2014 21:55:13 +0100 Subject: Extract fec-3.0.1 --- fec.c | 66 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 66 insertions(+) create mode 100644 fec.c (limited to 'fec.c') diff --git a/fec.c b/fec.c new file mode 100644 index 0000000..35960c3 --- /dev/null +++ b/fec.c @@ -0,0 +1,66 @@ +/* Utility routines for FEC support + * Copyright 2004, Phil Karn, KA9Q + */ + +#include +#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, +}; + -- cgit v1.2.3