函数调用和汇编 [英] Function Calls and Assembly

问题描述

我试图了解程序如何使用汇编x86代码进行函数调用(使用C语义).任何帮助将不胜感激.

Im trying to understand how a program makes a function call (using C semantics) with assembly x86 code. Any help would be greatly appreciated.

我找不到任何来源专门回答这个问题.

I could not find any sources to specifically answer this question.

推荐答案

在x86中，有称为 call 和 ret 的指令来执行此操作. call 将当前地址存储在堆栈上，并将jmp存储到作为参数传递的标签上.然后，名为 ret 的指令会弹出该地址，并在向该地址添加一个字节后跳转到该地址.

In x86, there are the instructions called call and ret to do this. call store the current address on stack and jmp to a label passed as argument. And the instruction called ret pop this address and jump to it after add one byte to that address.

代码示例:

C

int sum(int a, int b)
{
  return a + b;
}

void f(void)
{
  sum(2, 2);
  g();
}

编译器可能会生成(类似x86的汇编示例):

A compiler might generate(x86-assembly-like example):

f:
  push 2
  push 2
  call sum
  call g
  ret

sum:
   pop eax
   pop ebx
   add eax, ebx
   ret

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