cpuid(0, eax, ebx, ecx, edx);
cpuid(0, &eax, &ebx, &ecx, &edx);
int mm_support(void){    int rval;    int eax, ebx, ecx, edx;            __asm__ __volatile__ (                          /* See if CPUID instruction is supported ... */                          /* ... Get copies of EFLAGS into eax and ecx */                          "pushf\n\t"                          "popl %0\n\t"                          "movl %0, %1\n\t"                                                    /* ... Toggle the ID bit in one copy and store */                          /*     to the EFLAGS reg */                          "xorl $0x200000, %0\n\t"                          "push %0\n\t"                          "popf\n\t"                                                    /* ... Get the (hopefully modified) EFLAGS */                          "pushf\n\t"                          "popl %0\n\t"                          : "=a" (eax), "=c" (ecx)                          :                          : "cc"                           );        if (eax == ecx)        return 0; /* CPUID not supported */        cpuid(0, eax, ebx, ecx, edx);    if (ebx == 0x756e6547 &&        edx == 0x49656e69 &&        ecx == 0x6c65746e) {                /* intel */    inteltest:        cpuid(1, eax, ebx, ecx, edx);        if ((edx & 0x00800000) == 0)            return 0;        rval = MM_MMX;        if (edx & 0x02000000)             rval |= MM_MMXEXT | MM_SSE;        if (edx & 0x04000000)             rval |= MM_SSE2;        return rval;    } else if (ebx == 0x68747541 &&               edx == 0x69746e65 &&               ecx == 0x444d4163) {        /* AMD */        cpuid(0x80000000, eax, ebx, ecx, edx);        if ((unsigned)eax < 0x80000001)            goto inteltest;        cpuid(0x80000001, eax, ebx, ecx, edx);        if ((edx & 0x00800000) == 0)            return 0;        rval = MM_MMX;        if (edx & 0x80000000)            rval |= MM_3DNOW;        if (edx & 0x00400000)            rval |= MM_MMXEXT;        return rval;    } else if (ebx == 0x69727943 &&               edx == 0x736e4978 &&               ecx == 0x64616574) {        /* Cyrix Section */        /* See if extended CPUID level 80000001 is supported */        /* The value of CPUID/80000001 for the 6x86MX is undefined           according to the Cyrix CPU Detection Guide (Preliminary           Rev. 1.01 table 1), so we'll check the value of eax for           CPUID/0 to see if standard CPUID level 2 is supported.           According to the table, the only CPU which supports level           2 is also the only one which supports extended CPUID levels.        */        if (eax != 2)             goto inteltest;        cpuid(0x80000001, eax, ebx, ecx, edx);        if ((eax & 0x00800000) == 0)            return 0;        rval = MM_MMX;        if (eax & 0x01000000)            rval |= MM_MMXEXT;        return rval;    } else {        return 0;    }}