如何在没有操作数的汇编中编写表达式？

Question

I'm trying to write this expression A = (B × (C + D × (E × F))) ÷ (E × (C + D)) using an instruction set where each instruction has no operands (except for the two that must have one each).

This is an example from the book that I've followed: The expression is z = x * y + w * u

The code:

PUSH x
PUSH y
MULT
PUSH w
PUSH u
MULT
ADD
STORE z

What I have done:

PUSH E
PUSH F
MULT
PUSH D
MULT 
PUSH C
ADD
PUSH B
MULT
STORE Z (store the result)
PUSH C
PUSH D
ADD
PUSH E
MULT
PUSH Z
DIVIDE
STORE A

I'm not sure about the way that I stored the result in and the division seems incorrect. Is there a better way to write the expression?

Updated:

PUSH C
PUSH D
ADD
PUSH E
MULT
PUSH E
PUSH F
MULT
PUSH D
MULT
PUSH C
ADD
PUSH B
MULT
DIVIDE
STORE A

Answer 1

You don't need Z : calculate Ex(C+D) , then calculate (B×(C+D×(E×F))) ; now you have the values you need for the final division, which can then be stored in A . In fact, except for avoiding redundant calculations, you should never need to use STORE until the very end.

If your division is incorrect (you don't specify what assembly language this is, so I can't tell), then most likely you have the arguments backwards. In that case, you'd want to leave out the first STORE Z and the PUSH Z .