_bit_byte
register int _stopbyte = _bit_byte(_nbits - 1), _value = -1; \
register int _stopbyte = _bit_byte(_nbits - 1), _value = -1; \
((name)[_bit_byte(bit)] & _bit_mask(bit))
((name)[_bit_byte(bit)] |= _bit_mask(bit))
((name)[_bit_byte(bit)] &= ~_bit_mask(bit))
register int _startbyte = _bit_byte(_start); \
register int _stopbyte = _bit_byte(_stop); \
register int _startbyte = _bit_byte(_start); \
register int _stopbyte = _bit_byte(_stop); \