#include <libcflat.h>

static void prep_cc(void)
{
	asm volatile(
	"	msr pmovsclr_el0, %0\n"
	"	msr pmccfiltr_el0, %1\n"
	"	msr pmcntenset_el0, %2\n"
	"	msr pmcr_el0, %3\n"
	"	isb\n"
	:
	: "r" (1 << 31), "r" (1 << 27), "r" (1 << 31),
	  "r" (1 << 6 | 1 << 2 | 1 << 0));
}

int main(void)
{
	unsigned long start, end;
	unsigned int sctlr;
	int i, zeros = 0;

	asm volatile("mrs %0, sctlr_el1" : "=&r" (sctlr));
	prep_cc();

	for (i = 0; i < 100000; ++i) {
		asm volatile(
		"	mrs %0, pmccntr_el0\n"
		"	msr sctlr_el1, %2\n"
		"	mrs %1, pmccntr_el0\n"
		"	isb\n"
		: "=&r" (start), "=&r" (end) : "r" (sctlr));

		if ((i % 10) == 0)
			printf("\n");

		printf(" %d", end - start);

		if ((end - start) == 0) {
			++zeros;
			prep_cc();
		}
	}

	printf("\nnum zero counts = %d\n", zeros);
	return 0;
}