Get x86 CPU Vender and Brand Name

cpuvender.c

//!(C)tmiz.net 
#include <stdio.h>
#define X86_VENDERNAME_ARRAY_LENGTH 13
#define X86_BRANDNAME_ARRAY_LENGTH 49
 
extern void GetX86CPUVenderName(char*outVendername);
extern void GetX86CPUBrandName(char*brandname);
 
int main() {
    char vender[X86_VENDERNAME_ARRAY_LENGTH];
    GetX86CPUVenderName(vender);
    printf("%s\n", vender);
 
    char brand[X86_BRANDNAME_ARRAY_LENGTH];
    GetX86CPUBrandName(brand);
    printf("%s\n", brand);
    return 0;
}
 
union CpuRegs {
    struct cpu_regs {
        unsigned int eax, ebx, ecx, edx;
    } e;
    struct cpu_regs_n {
        unsigned int val[4];
    } n;
};
 
void x86CPUIDOperate(unsigned int op, CpuRegs *outCpuRegs)
{
    __asm__ volatile(
        "xchgl %%ebx, %1 \n\t"
        "cpuid         \n\t"
        "xchgl %%ebx, %1 \n\t"
        : "=a"(outCpuRegs->e.eax),
          "=b"(outCpuRegs->e.ebx),
          "=c"(outCpuRegs->e.ecx),
          "=d"(outCpuRegs->e.edx)
        : "a"(op));
}
 
void int2Ascii(int in, char* out){
    if(!out) return;
    //x86なのでLittle Endian
    for(int i= 0; i< 4; i++) {
        out[i] = (in >> (i*8)) & 0x000000ff;
    }
}
 
void GetX86CPUVenderName(char* vendername)
{
    //vendername must be 13 chars
    CpuRegs inCpuRegs;
    x86CPUIDOperate(0,  &inCpuRegs);
 
    //building strings by order of ebx,edx,ecx.
    int2Ascii(inCpuRegs.e.ebx, &vendername[0]);
    int2Ascii(inCpuRegs.e.edx, &vendername[4]);
    int2Ascii(inCpuRegs.e.ecx, &vendername[8]);
    vendername[13] = 0;//insert NULL char as a last word.
}
 
void GetX86CPUBrandName(char*brandname)
{
    //brandname must be 49 chars
    int i;
    CpuRegs result_regs[3];
    for(i= 0; i< 3; i++) {
        x86CPUIDOperate(0x80000002+ i, &(result_regs[i]));
    }
    for(i= 0; i< 12; i++) {
        int2Ascii(result_regs[i/4].n.val[i%4], &brandname[i*4]);
    }
    brandname[49] = 0;//insert NULL char as a last word.
}