--- /dev/null
+/* Conversion lookup tables from conventional alpha to Berlekamp's
+ * dual-basis representation. Used in the CCSDS version only.
+ * taltab[] -- convert conventional to dual basis
+ * tal1tab[] -- convert dual basis to conventional
+
+ * Note: the actual RS encoder/decoder works with the conventional basis.
+ * So data is converted from dual to conventional basis before either
+ * encoding or decoding and then converted back.
+ *
+ * Copyright 2002 Phil Karn, KA9Q
+ * May be used under the terms of the GNU General Public License (GPL)
+ */
+#include <stdio.h>
+unsigned char Taltab[256],Tal1tab[256];
+
+static unsigned char tal[] = { 0x8d, 0xef, 0xec, 0x86, 0xfa, 0x99, 0xaf, 0x7b };
+
+/* Generate conversion lookup tables between conventional alpha representation
+ * (@**7, @**6, ...@**0)
+ * and Berlekamp's dual basis representation
+ * (l0, l1, ...l7)
+ */
+int main(){
+ int i,j,k;
+
+ for(i=0;i<256;i++){/* For each value of input */
+ Taltab[i] = 0;
+ for(j=0;j<8;j++) /* for each column of matrix */
+ for(k=0;k<8;k++){ /* for each row of matrix */
+ if(i & (1<<k))
+ Taltab[i] ^= tal[7-k] & (1<<j);
+ }
+ Tal1tab[Taltab[i]] = i;
+ }
+ printf("unsigned char Taltab[] = {\n");
+ for(i=0;i<256;i++){
+ if((i % 16) == 0)
+ printf("\n");
+ printf("0x%02x,",Taltab[i]);
+ }
+ printf("\n};\n\nunsigned char Tal1tab[] = {");
+ for(i=0;i<256;i++){
+ if((i % 16) == 0)
+ printf("\n");
+ printf("0x%02x,",Tal1tab[i]);
+ }
+ printf("\n};\n");
+ exit(0);
+}
+