LOADPTR   RD, RP
          RD, RP, addr_type
          RD, RP, addr_type, d_size
          RD, RP, addr_type, d_size, p_p_inc_dec-3
          RD, RP, addr_type, d_size, p_p_inc_dec-3, relative-1
          RD, RP, addr_type, d_size, p_p_inc_dec-3, relative-1, R2 or p_immediate
          RD, RP, addr_type, d_size, p_p_inc_dec-3, relative-1, R2 or p_immediate, R3 or shift_immediate

