GNU Radio 2.x: fixed.h Source File

00001 /* Configure the RS codec with fixed parameters for CCSDS standard
00002  * (255,223) code over GF(256). Note: the conventional basis is still
00003  * used; the dual-basis mappings are performed in [en|de]code_rs_ccsds.c
00004  *
00005  * Copyright 2002 Phil Karn, KA9Q
00006  * May be used under the terms of the GNU General Public License (GPL)
00007  */
00008 #define DTYPE unsigned char
00009 
00010 static inline int mod255(int x){
00011   while (x >= 255) {
00012     x -= 255;
00013     x = (x >> 8) + (x & 255);
00014   }
00015   return x;
00016 }
00017 #define MODNN(x) mod255(x)
00018 
00019 extern unsigned char CCSDS_alpha_to[];
00020 extern unsigned char CCSDS_index_of[];
00021 extern unsigned char CCSDS_poly[];
00022 
00023 #define MM 8
00024 #define NN 255
00025 #define ALPHA_TO CCSDS_alpha_to
00026 #define INDEX_OF CCSDS_index_of
00027 #define GENPOLY CCSDS_poly
00028 #define NROOTS 32
00029 #define FCR 112
00030 #define PRIM 11
00031 #define IPRIM 116
00032 #define A0 (NN)
00033 
00034 #define ENCODE_RS encode_rs_8
00035 #define DECODE_RS decode_rs_8
00036 
00037 void ENCODE_RS(DTYPE *data,DTYPE *parity);
00038 int DECODE_RS(DTYPE *data, int *eras_pos, int no_eras);