使用GCC扩展ASM将嵌入式Intel ASM转换为AT& T ASM [英] Convert inline Intel ASM to AT&T ASM with GCC Extended ASM

问题描述

我花了最后两天的时间研究AT& T内联汇编，但是在转换这一行时遇到了一些问题:

I've spent the last 2 days to study AT&T inline assembly, but I'm having some problems converting this one:

static char vendername[50] = {0};
_asm {
    mov     eax, 0
    cpuid
    mov     dword ptr [vendername], ebx
    mov     dword ptr [vendername+4], edx
    mov     dword ptr [vendername+8], ecx
}

这是我的尝试:

static char vendername[50] = {0};
__asm__(
    "movl $0,%%eax \n"
    "cpuid \n"
    "movl %%ebx, %[vendername] \n"
    "movl %%edx, %[vendername+$4] \n"
    "movl %%ecx, %[vendername+$8] \n"
    :"=r"(vendername) //user vendername as output
    :[vendername]"m"(vendername) //use vendername as input
    :"eax","ebx","edx","ecx" // clobbers those regs
);

此代码不起作用，gcc给我以下错误:

This code doesn't work, gcc give me the following errors:

error: undefined named operand ‘vendername+4’

和

error: undefined named operand ‘vendername+8’

如何将代码从英特尔程序集转换为AT& T程序集?

How do I convert the code from Intel assembly to AT&T assembly?

推荐答案

您可以按照以下步骤操作:

You can do it as:

#include <stdio.h>

int main(int argc, char **argv) {
  static char vendername[50] = {0};

  __asm__ __volatile__ (
    "movl $0, %%eax\n"
    "cpuid\n"
    "movl %%ebx, %0\n"
    "movl %%edx, %0 + 4\n"
    "movl %%ecx, %0 + 8\n"
    :"=m"(vendername)
    :
    :"eax", "ebx", "edx", "ecx"
  );

  printf("%s\n", vendername);

  return 0;
}

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