+ 43210
+ bits mdcba
+
+These parameters works as following code.
+
+ uint32_t layer_state;
+ uint8_t shift = part*4;
+ uint32_t mask = (bits&0x10) ? ~((uint32_t)0xf<<shift) : 0;
+ switch (<bitop>) {
+ case BIT_AND:
+ layer_state = layer_state & (((bits&0xf)<<shift)|mask);
+ break;
+ case BIT_OR:
+ layer_state = layer_state | (((bits&0xf)<<shift)|mask);
+ break;
+ case BIT_XOR:
+ layer_state = layer_state ^ (((bits&0xf)<<shift)|mask);
+ break;
+ case BIT_SET:
+ layer_state = layer_state <bitop> (((bits&0xf)<<shift)|mask);
+ break;