GNUmifluz: M_16_SWAP

{ \
 u_int16_t _tmp; \
 _tmp = (u_int16_t)a; \
 ((u_int8_t *)&a)[0] = ((u_int8_t *)&_tmp)[1]; \
 ((u_int8_t *)&a)[1] = ((u_int8_t *)&_tmp)[0]; \
}