{name: "MULL", argLength: 2, reg: gp21, asm: "SMULL", commutative: true},                                      // arg0 * arg1, signed, 32-bit mult results in 64-bit
		{name: "UMULL", argLength: 2, reg: gp21, asm: "UMULL", commutative: true},                                     // arg0 * arg1, unsigned, 32-bit mult results in 64-bit
		{name: "DIV", argLength: 2, reg: gp21, asm: "SDIV"},                                                           // arg0 / arg1, signed

	if rsa.amount == 0 && rsa.extShift == lsl {
		rsa.extShift = ExtShift(0)
	} else if rsa.amount > max {
		return nil
	}
	return rsa
}

func handle_MemExtend(x uint32, mult uint8, absent bool) Arg {
	var extend ExtShift
	var Rm Reg
	option := (x >> 13) & (1<<3 - 1)
	Rn := RegSP(X0) + RegSP(x>>5&(1<<5-1))
	if (option & 1) != 0 {
		Rm = Reg(X0) + Reg(x>>16&(1<<5-1))
	} else {

    assert lhs_ty, rhs_ty
    if isinstance(op, ast.Sub):
      code = 'arith.sub'
    elif isinstance(op, ast.Add):
      code = 'arith.add'
    elif isinstance(op, ast.Mult):
      code = 'arith.mul'
    elif isinstance(op, ast.Div):
      code = 'arith.div'
    else:
      raise NotImplementedError('BinOp operator not recognized' + op)