// Note: If the following code is not optimized by compiler, it
    // can be replaced with the following:
    // if (syndrome & ((1 << 30) | (1 << 31)))
    if (syndrome == 0xffffffff
        || syndrome == (1 << 30)
        || syndrome == (1 << 31)) {
      // Bits 30 and 31 (30* and 29*) can't be incorrect
      // if previous word wad decoded correctly
      bad++;
      return false;
    }

/*
  The following code was used to generate the syndromes table

void generate_syndromes() {
  unsigned long syndromes[64];
  memset(syndromes, 0xff, sizeof(syndromes));
  syndromes[0] = 0;
  for (int i = 0; i < 32; i++) {
    long bit = 1UL << i;
    long syndrome = GpsParity::calcParity(bit);
    syndromes[syndrome & 0x3f] = bit;
  }
  printf("static long syndromes[64] = {\n");
  for (int i = 0; i < 64; i+=4) {
    printf(" ");
    for (int j = 0; j < 4; j++)
      printf(" 0x%08x,", syndromes[i+j]);
    printf("\n");
  }
  printf("};\n");
}
*/