#include <stdio.h>
#include <stdlib.h>

int a = 10;
int b = 20;
int result;
 
int main()
{
    asm
    (
        "pusha\n\t"
        "movl a,%eax\n\t"
        "movl b,%ebx\n\t"
        "imull %ebx,%eax\n\t"
        "movl %eax,result\n\t"
        "popa"
    );

    printf("%d\n",result);   
    return 0;
}

上面的代码是教科书里的，教程中说内联汇编要访问的变量必须是全局的，我认为程序没有问题，但编译运行时报错：

Compiler: Default compiler
Executing  gcc.exe...
gcc.exe "E:\xx\test\test.c" -o "E:\xx\test\test.exe"    -I"d:\Dev-Cpp\include"   -L"d:\Dev-Cpp\lib"
C:\DOCUME~1\xxx\LOCALS~1\Temp/ccUlaaaa.o(.text+0x38):test.c: undefined reference to `a'
C:\DOCUME~1\xxx\LOCALS~1\Temp/ccUlaaaa.o(.text+0x3e):test.c: undefined reference to `b'
C:\DOCUME~1\xxx\LOCALS~1\Temp/ccUlaaaa.o(.text+0x46):test.c: undefined reference to `result'collect2: ld returned 1 exit status

Execution terminated

请教大家，问题出在哪里？？3x