如何在Linux中调用"cpuid"？

Question

在为Windows编写新代码时,我偶然发现_cpuinfo()了Windows API.因为我主要处理Linux环境(GCC),所以我希望能够访问CPUInfo.

我尝试过以下方法:

#include <iostream>

int main()
{
  int a, b;

  for (a = 0; a < 5; a++)
  {
    __asm ( "mov %1, %%eax; "            // a into eax
          "cpuid;"
          "mov %%eax, %0;"             // eax into b
          :"=r"(b)                     // output
          :"r"(a)                      // input
          :"%eax","%ebx","%ecx","%edx" // clobbered register
         );
    std::cout << "The code " << a << " gives " << b << std::endl;
  }

  return 0;
}

这使用组件,但我不想重新发明轮子.有没有其他方法可以在没有汇编的情况下实现CPUInfo？

编译器错误:

lewis@lewis-desktop:~/Desktop/prog$ g++ -Wall CPUInfo.cpp
CPUInfo.cpp: In function ‘int main()’:
CPUInfo.cpp:10:22: error: expected ‘)’ before ‘;’ token
CPUInfo.cpp:10:23: error: expected primary-expression before ‘)’ token
CPUInfo.cpp:10:23: error: expected ‘;’ before ‘)’ token
CPUInfo.cpp:8:8: warning: unused variable ‘b’ [-Wunused-variable]
CPUInfo.cpp:12:8: error: expected ‘}’ at end of input

Answer 1

由于您正在使用GCC进行编译,因此您可以包含cpuid.h声明这些函数的内容:

/* Return highest supported input value for cpuid instruction.  ext can
   be either 0x0 or 0x8000000 to return highest supported value for
   basic or extended cpuid information.  Function returns 0 if cpuid
   is not supported or whatever cpuid returns in eax register.  If sig
   pointer is non-null, then first four bytes of the signature
   (as found in ebx register) are returned in location pointed by sig.  */
unsigned int __get_cpuid_max (unsigned int __ext, unsigned int *__sig)

/* Return cpuid data for requested cpuid level, as found in returned
   eax, ebx, ecx and edx registers.  The function checks if cpuid is
   supported and returns 1 for valid cpuid information or 0 for
   unsupported cpuid level.  All pointers are required to be non-null.  */
int __get_cpuid (unsigned int __level,
    unsigned int *__eax, unsigned int *__ebx,
    unsigned int *__ecx, unsigned int *__edx)

您不需要也不应该重新实现此功能.

Answer 2

for (a =0; a < 5; ++a;)

那里应该只有两个分号.你有三个.

这是基本的C/C++语法; CPUID是一个红色的鲱鱼.