algorithm calculate CRC7 for MMC

WORD addCRC(WORD crc,BYTE value) {
   crc  = (int)(crc >> 8) | (crc << 8);
   crc ^= value;
   crc ^= (int)(crc & 0xff) >> 4;
   crc ^= (crc << 8) << 4;
   crc ^= ((crc & 0xff) << 4) << 1;
	return crc;
}

CRC16:
  crc = 0;
  for(i = 0; i < bits; i++) {
    ix = i / 8;
    mask = 1 << (7-(i & 7));

    xor = (crc & 0x8000) ^ (in[ix] & mask) ? 1 : 0;
    crc <<= 1;
    if(xor != 0) {
      crc ^= 0x1021;
    }
    crc &= 0xffff;
    printf("i %4i  in 0x%02X  ix %2i   mask %3i  crc 0x%04X  xor 0x%04X\n",
      i, in[ix], ix, mask, crc, xor);
  }


CRC7:
  crc = 0;
  for(i = 0; i < bits; i++) {
    ix = i / 8;
    mask = 1 << (7-(i & 7));

    xor = (crc & 0x40) ^ (in[ix] & mask) ? 1 : 0;
    crc <<= 1;
    if(xor != 0) {
      crc ^= 0x9;
    }
    crc &= 0x7f;
    printf("i %2i   ix %i   mask %3i  crc 0x%02X  xor 0x%02X  res 0x%02X\n",
      i, ix, mask, crc, xor, crc*2+1);
  }