#include <sys/types.h>
#include <unistd.h>
#include <stdlib.h>
#include <stdio.h>

typedef struct {
	unsigned int version:8;
	unsigned int num_cnt:8;
	unsigned int cnt_width:8;
	unsigned int ebx_length:8;
} pmu_eax_t;

static inline void cpuid(unsigned int op, unsigned int *eax, unsigned int *ebx, unsigned int *ecx, unsigned int *edx)
{
	__asm__("cpuid"
			: "=a" (*eax),
			"=b" (*ebx),
			"=c" (*ecx),
			"=d" (*edx)
			: "0" (op), "c"(0));
}

int main(void)
{
	unsigned int ecx, ebx, edx;
	union {
		unsigned int val;
		pmu_eax_t eax;
	} eax;

	cpuid(0, &eax.val, &ebx, &ecx, &edx);
	if (eax.val < 0xa) {
		printf("does not support architected PMU\n");
		return 0;
	}
	cpuid(0xa, &eax.val, &ebx, &ecx, &edx);
	
	printf("eax=0x%lx: version=%d  num_cnt=%d\n",
	       eax.val,
	       eax.eax.version,
	       eax.eax.num_cnt);
	return 0;
}