/*
 *  This file is part of the optimized implementation of the Picnic signature scheme.
 *  See the accompanying documentation for complete details.
 *
 *  The code is provided under the MIT license, see LICENSE for
 *  more details.
 *  SPDX-License-Identifier: MIT
 */

#ifndef CPU_H
#define CPU_H

#include "macros.h"

#if !defined(OQS)
/* Check if support for __builtin_cpu_supports is available and known to be working. As tests have
 * showed, support for it on Mac OS X and MinGW is not reliable. */
#if (defined(__GNUC__) || __has_builtin(__builtin_cpu_supports)) && !defined(__APPLE__) &&         \
    !defined(__MINGW32__) && !defined(__MINGW64__) && !defined(WITHOUT_BUILTIN_CPU_SUPPORTS)
#define BUILTIN_CPU_SUPPORTED
#endif

#if defined(BUILTIN_CPU_SUPPORTED) && GNUC_CHECK(4, 9) && !GNUC_CHECK(5, 0)
/* gcc 4.9's __builtin_cpu_support does not support "bmi2" */
#define BUILTIN_CPU_SUPPORTED_BROKEN_BMI2
#endif

#if !defined(BUILTIN_CPU_SUPPORTED) || defined(BUILTIN_CPU_SUPPORTED_BROKEN_BMI2)
#include <stdbool.h>

/* CPU supports SSE2 */
#define CPU_CAP_SSE2 0x00000001
/* CPU supports AVX2 */
#define CPU_CAP_AVX2 0x00000004
/* CPU supports BMI2 */
#define CPU_CAP_BMI2 0x00000010
/* CPU supports NEON */
#define CPU_CAP_NEON 0x00000008

/**
 * Helper function in case __builtin_cpu_supports is not available.
 */
bool cpu_supports(unsigned int caps);
#endif

/* Use __builtin_cpu_support or our fallback function to determine supported CPU features */
#if defined(__x86_64__) || defined(_M_X64) || defined(__i386__) || defined(_M_IX86)
#if defined(BUILTIN_CPU_SUPPORTED) && !defined(BUILTIN_CPU_SUPPORTED_BROKEN_BMI2)
#define CPU_SUPPORTS_AVX2 (__builtin_cpu_supports("avx2") && __builtin_cpu_supports("bmi2"))
#else
#define CPU_SUPPORTS_AVX2 cpu_supports(CPU_CAP_AVX2 | CPU_CAP_BMI2)
#endif
#endif

#if defined(__x86_64__) || defined(_M_X64)
// X86-64 CPUs always support SSE2
#define CPU_SUPPORTS_SSE2 1
#elif defined(__i386__) || defined(_M_IX86)
#if defined(BUILTIN_CPU_SUPPORTED)
#define CPU_SUPPORTS_SSE2 __builtin_cpu_supports("sse2")
#else
#define CPU_SUPPORTS_SSE2 cpu_supports(CPU_CAP_SSE2)
#endif
#else
#define CPU_SUPPORTS_SSE2 0
#endif

#if defined(__aarch64__)
#define CPU_SUPPORTS_NEON 1
#elif defined(__arm__)
#define CPU_SUPPRTS_NEON cpu_supports(CPU_CAP_NEON)
#else
#define CPU_SUPPORTS_NEON 0
#endif
#else
/* Use OQS function to determine supported CPU features */
#include <oqs/common.h>

#if defined(__x86_64__) || defined(_M_X64) || defined(__i386__) || defined(_M_IX86)
#define CPU_SUPPORTS_AVX2                                                                          \
  (OQS_CPU_has_extension(OQS_CPU_EXT_AVX2) && OQS_CPU_has_extension(OQS_CPU_EXT_BMI2))
#else
#define CPU_SUPPORTS_AVX2 0
#endif

#if defined(__x86_64__) || defined(_M_X64)
// X86-64 CPUs always support SSE2
#define CPU_SUPPORTS_SSE2 1
#elif defined(__i386__) || defined(_M_IX86)
#define CPU_SUPPORTS_SSE2 OQS_CPU_has_extension(OQS_CPU_EXT_SSE2)
#else
#define CPU_SUPPORTS_SSE2 0
#endif

#if defined(__aarch64__)
#define CPU_SUPPORTS_NEON 1
#elif defined(__arm__)
#define CPU_SUPPORTS_NEON OQS_CPU_has_extension(OQS_CPU_EXT_ARM_NEON)
#else
#define CPU_SUPPORTS_NEON 0
#endif
#endif

#endif