/** Measure time and sleep with IA-32 time-stamp counter.
 *
 * @file
 * @author Steffen Vogel <svogel2@eonerc.rwth-aachen.de>
 * @copyright 2014-2022, Institute for Automation of Complex Power Systems, EONERC
 * @license GNU General Public License (version 3)
 *
 * VILLAScommon
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *********************************************************************************/

#pragma once

#if !(__x86_64__ || __i386__)
  #error this header is for x86 only
#endif

#include <cpuid.h>
#include <cinttypes>
#include <x86intrin.h>

#include <villas/kernel/kernel.hpp>

#ifndef bit_TSC
  #define bit_TSC (1 << 4)
#endif

#define bit_TSC_INVARIANT	(1 << 8)
#define bit_RDTSCP		(1 << 27)

struct Tsc {
	uint64_t frequency;

	bool rdtscp_supported;
	bool is_invariant;
};

__attribute__((unused))
static uint64_t tsc_now(struct Tsc *t)
{
	uint32_t tsc_aux;
	return t->rdtscp_supported
		? __rdtscp(&tsc_aux)
		: __rdtsc();
}

int tsc_init(struct Tsc *t) __attribute__ ((warn_unused_result));

uint64_t tsc_rate_to_cycles(struct Tsc *t, double rate);