int checksumDCW(uint8_t *data);
int isnullDCW(uint8_t *data);
int isbadDCW(uint8_t *data);
int acceptDCW(uint8_t *data);

int similarcw( uint8_t *cw1, uint8_t *cw2 );
// for nds
int ishalfnulledcw( uint8_t dcw[16] );