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| /* 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,
| };
|
|
