Question

我想执行asm代码行的循环。其实我正在尝试读取我的核心的CPUID，需要读取CPUID的所有参数。如果我将0写入eax寄存器，那么我将获得制造商名称，如果我将1写入eax，则将收到下一组CPUID信息。等等... 现在我想执行最多15组asm指令以获得完整的CPUID输出。

例： unsigned int cpuid_reg [4];

    __asm__ volatile("mov $1, %eax");
    __asm__ volatile("cpuid" : "=a" (cpuid_reg[0]), "=b" (cpuid_reg[1]), "=c" (cpuid_reg[2]), "=d" (cpuid_reg[3]));
    printf("reg[0] 0x%x , cpuid_reg[1] 0x%x, cpuid_reg[2] 0x%x, cpuid_reg[3] 0x%x\n", cpuid_reg[0], cpuid_reg[1], cpuid_reg[2], cpuid_reg[3]);


    __asm__ volatile("mov $2, %eax");
    __asm__ volatile("cpuid" : "=a" (cpuid_reg[0]), "=b" (cpuid_reg[1]), "=c" (cpuid_reg[2]), "=d" (cpuid_reg[3]));
    printf("cpuid_reg[0] 0x%x , cpuid_reg[1] 0x%x, cpuid_reg[2] 0x%x, cpuid_reg[3] 0x%x\n", cpuid_reg[0], cpuid_reg[1], cpuid_reg[2], cpuid_reg[3]);

代替这两组代码，我需要一组我可以将0到15写入'eax'寄存器以获取完整的CPUID数据。谢谢你的帮助。

Answer 1

您可以阅读this和this

等内容

static inline void cpuid(int code, uint32_t *a, uint32_t *d) {
  asm volatile("cpuid":"=a"(*a),"=d"(*d):"a"(code):"ecx","ebx");
}

/** issue a complete request, storing general registers output as a string
 */
static inline int cpuid_string(int code, uint32_t where[4]) {
  asm volatile("cpuid":"=a"(*where),"=b"(*(where+1)),
               "=c"(*(where+2)),"=d"(*(where+3)):"a"(code));
  return (int)where[0];
}

在汇编指令中添加变量（asm内联C示例）

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