ppsspp/libretro/libretro-common/include/features/features_cpu.h

/* Copyright  (C) 2010-2020 The RetroArch team
 *
 * ---------------------------------------------------------------------------------------
 * The following license statement only applies to this file (features_cpu.h).
 * ---------------------------------------------------------------------------------------
 *
 * Permission is hereby granted, free of charge,
 * to any person obtaining a copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation the rights to
 * use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software,
 * and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
 * INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
 * IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
 * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 */

#ifndef _LIBRETRO_SDK_CPU_INFO_H
#define _LIBRETRO_SDK_CPU_INFO_H

#include <retro_common_api.h>

#include <stdint.h>

#include <libretro.h>

RETRO_BEGIN_DECLS

/**
 * Gets the time in ticks since some unspecified epoch.
 * The notion of a "tick" varies per platform.
 *
 * The epoch may change between devices or across reboots.
 *
 * Suitable for use as a default implementation of \c retro_perf_callback::get_perf_counter,
 * (or as a fallback by the core),
 * although a frontend may provide its own implementation.
 *
 * @return The current time, in ticks.
 * @see retro_perf_callback::get_perf_counter
 */
retro_perf_tick_t cpu_features_get_perf_counter(void);

/**
 * Gets the time in microseconds since some unspecified epoch.
 *
 * The epoch may change between devices or across reboots.
 *
 * Suitable for use as a default implementation of \c retro_perf_callback::get_time_usec,
 * (or as a fallback by the core),
 * although a frontend may provide its own implementation.
 *
 * @return The current time, in microseconds.
 * @see retro_perf_callback::get_time_usec
 */
retro_time_t cpu_features_get_time_usec(void);

/**
 * retro_sleep_until_us:
 * @deadline : an instant on cpu_features_get_time_usec()'s clock.
 *
 * Sleeps until that clock reads at least @deadline. Absolute where the
 * platform offers it (clock_nanosleep TIMER_ABSTIME on Linux and
 * Android, mach_wait_until on Darwin), a re-armed high-resolution
 * relative wait elsewhere. Never early against that clock; may be
 * late, as every sleep may. Not available to the salamander launchers,
 * which do not link features_cpu.c.
 **/
void retro_sleep_until_us(retro_time_t deadline);

/**
 * Returns the available features (mostly SIMD extensions)
 * supported by this CPU.
 *
 * Suitable for use as a default implementation of \c retro_perf_callback::get_time_usec,
 * (or as a fallback by the core),
 * although a frontend may provide its own implementation.
 *
 * @return Bitmask of all CPU features available.
 * @see RETRO_SIMD
 * @see retro_perf_callback::get_cpu_features
 */
uint64_t cpu_features_get(void);

#if (defined(__x86_64__) || defined(__i386__) || defined(__i486__) || defined(__i686__) || (defined(_M_X64) && _MSC_VER > 1310) || (defined(_M_IX86) && _MSC_VER > 1310)) && !defined(__MACH__)
/**
 * Executes the x86 CPUID instruction for the requested leaf, writing the
 * EAX, EBX, ECX and EDX result registers into flags[0], flags[1], flags[2]
 * and flags[3] respectively. Available on x86/x86-64 targets only.
 *
 * @param func     The CPUID leaf (function number) to query.
 * @param[out] flags Array of four 32-bit words receiving EAX/EBX/ECX/EDX.
 */
void x86_cpuid(uint32_t func, int32_t flags[4]);
#endif

/**
 * @return The number of logical processors available -- hardware
 * threads rather than physical cores, so an SMT part reports both of
 * each core -- or 1 if it could not be determined.
 *
 * @see cpu_features_get_core_amount_physical
 */
unsigned cpu_features_get_core_amount(void);

/**
 * The count to size work by where a thread wants a core to itself,
 * rather than the thread count cpu_features_get_core_amount() returns.
 *
 * @return The number of physical cores available, or the value
 * cpu_features_get_core_amount() gives where the distinction cannot be
 * drawn, which is never larger and so stays a safe answer.
 */
unsigned cpu_features_get_core_amount_physical(void);

/**
 * Order the processors best-first, for a caller pinning a thread that
 * wants the strongest processor still free.
 *
 * Entries are operating system processor identifiers, the numbering an
 * affinity mask is built from, ordered by descending core performance
 * (the fast class first, then the larger last-level cache, then the
 * higher clock) and with an SMT sibling placed after the processor it
 * shares a core with. Processors outside the calling thread's affinity
 * mask are left out. Where the platform publishes no topology the order is simply
 * ascending, which names every processor exactly once and so remains
 * usable, just unranked.
 *
 * @param s   Receives the identifiers.
 * @param len Number of entries @s has room for.
 * @return The number of entries written, which is 0 where no
 * identifiers could be established and the caller should leave
 * affinity alone.
 */
size_t cpu_features_get_processor_order(unsigned *s, size_t len);

/**
 * Returns the name of the CPU model.
 *
 * @param[out] name Pointer to a buffer to store the name.
 * Will be \c NULL-terminated.
 * If \c NULL, this value will not be modified.
 * @param len The amount of space available in \c name.
 */
void cpu_features_get_model_name(char *name, int len);

RETRO_END_DECLS

#endif