pushl/popl％esp的程序集级表示是什么?

问题描述

C ++

ATT组装

我正在尝试了解以下两条说明的行为:

I'm trying to understand the behavior of the following two instructions:

pushl %esp

并且:

popl %esp

请注意，它们会将计算出的值存储回%esp.

Note that they store the computed value back into %esp.

我正在独立考虑这些说明，而不是按顺序考虑.我知道存储在%esp中的值始终是增量/减量之前的值，但是我怎么用汇编语言表示行为呢?到目前为止，这是我想出的:

I'm considering these instructions independently, not in sequence. I know that the value stored in %esp is always the value before the increment/decrement, but how could I represent the behavior in assembly language? This is what I've come up with so far:

用于推送:

movl %esp, %edx     1. save value of %esp
subl  $4, %esp      2. decrement stack pointer
movl %edx, (%esp)   3. store old value of %esp on top of stack

对于流行音乐:

movl (%esp), %esp   You wouldn’t need the increment portion.

这是正确的吗?如果没有，我哪里出问题了?谢谢.

Is this correct? If not, where am I going wrong? Thanks.

推荐答案

如英特尔®64和IA-32体系结构开发人员手册:合并卷:

The PUSH ESP instruction pushes the value of the ESP register as it existed
before the instruction was executed. If a PUSH instruction uses a memory operand
in which the ESP register is used for computing the operand address, the address
of the operand is computed before the ESP register is decremented.

关于pop esp:

The POP ESP instruction increments the stack pointer (ESP) before data at the old
top of stack is written into the destination.

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