汇编中的复杂 IF 语句 [英] complex IF statement in assembly

问题描述

How should I write such an if statement in assembly?

if ((a == b AND a > c) OR c == b) { ...

Platform: Intel 32-bit machine, NASM syntax.

Update

For variable types and value, use whatever is more easy to understand. Integers would works fine for me, I guess.

解决方案

In generic assembly, it will be basically something like this (a in ax, b in bx, c in cx):

    cmp  bx, cx
    jeq  istrue
    cmp  ax, cx
    jle  isfalse
    cmp  ax, bx
    jeq  istrue
isfalse:
    ; do false bit
    jmp  nextinstr
istrue:
    ; do true bit

nextinstr:
    ; carry on

If there's no false bit, it can be simplified to:

    cmp  bx, cx
    jeq  istrue
    cmp  ax, bx
    jne  nextinstr
    cmp  ax, cx
    jle  nextinstr
istrue:
    ; do true bit

nextinstr:
    ; carry on

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