/*

 * Copyright (c) 2016-present, Yann Collet, Facebook, Inc.

 * All rights reserved.

 *

 * This source code is licensed under both the BSD-style license (found in the

 * LICENSE file in the root directory of this source tree) and the GPLv2 (found

 * in the COPYING file in the root directory of this source tree).

 * You may select, at your option, one of the above-listed licenses.

 */

#ifndef ZSTD_COMPILER_H

#define ZSTD_COMPILER_H

/*-*******************************************************

*  Compiler specifics

*********************************************************/

/* force inlining */

#if !defined(ZSTD_NO_INLINE)

#if defined (__GNUC__) || defined(__cplusplus) || defined(__STDC_VERSION__) && __STDC_VERSION__ >= 199901L   /* C99 */

#  define INLINE_KEYWORD inline

#else

#  define INLINE_KEYWORD

#endif

#if defined(__GNUC__) || defined(__ICCARM__)

#  define FORCE_INLINE_ATTR __attribute__((always_inline))

#elif defined(_MSC_VER)

#  define FORCE_INLINE_ATTR __forceinline

#else

#  define FORCE_INLINE_ATTR

#endif

#else

#define INLINE_KEYWORD

#define FORCE_INLINE_ATTR

#endif

/**

 * FORCE_INLINE_TEMPLATE is used to define C "templates", which take constant

 * parameters. They must be inlined for the compiler to eliminate the constant

 * branches.

 */

#define FORCE_INLINE_TEMPLATE static INLINE_KEYWORD FORCE_INLINE_ATTR

/**

 * HINT_INLINE is used to help the compiler generate better code. It is *not*

 * used for "templates", so it can be tweaked based on the compilers

 * performance.

 *

 * gcc-4.8 and gcc-4.9 have been shown to benefit from leaving off the

 * always_inline attribute.

 *

 * clang up to 5.0.0 (trunk) benefit tremendously from the always_inline

 * attribute.

 */

#if !defined(__clang__) && defined(__GNUC__) && __GNUC__ >= 4 && __GNUC_MINOR__ >= 8 && __GNUC__ < 5

#  define HINT_INLINE static INLINE_KEYWORD

#else

#  define HINT_INLINE static INLINE_KEYWORD FORCE_INLINE_ATTR

#endif

/* UNUSED_ATTR tells the compiler it is okay if the function is unused. */

#if defined(__GNUC__)

#  define UNUSED_ATTR __attribute__((unused))

#else

#  define UNUSED_ATTR

#endif

/* force no inlining */

#ifdef _MSC_VER

#  define FORCE_NOINLINE static __declspec(noinline)

#else

#  if defined(__GNUC__) || defined(__ICCARM__)

#    define FORCE_NOINLINE static __attribute__((__noinline__))

#  else

#    define FORCE_NOINLINE static

#  endif

#endif

/* target attribute */

#ifndef __has_attribute

  #define __has_attribute(x) 0  /* Compatibility with non-clang compilers. */

#endif

#if defined(__GNUC__) || defined(__ICCARM__)

#  define TARGET_ATTRIBUTE(target) __attribute__((__target__(target)))

#else

#  define TARGET_ATTRIBUTE(target)

#endif

/* Enable runtime BMI2 dispatch based on the CPU.

 * Enabled for clang & gcc >=4.8 on x86 when BMI2 isn't enabled by default.

 */

#ifndef DYNAMIC_BMI2

  #if ((defined(__clang__) && __has_attribute(__target__)) \

      || (defined(__GNUC__) \

          && (__GNUC__ >= 5 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 8)))) \

      && (defined(__x86_64__) || defined(_M_X86)) \

      && !defined(__BMI2__)

  #  define DYNAMIC_BMI2 1

  #else

  #  define DYNAMIC_BMI2 0

  #endif

#endif

/* prefetch

 * can be disabled, by declaring NO_PREFETCH build macro */

#if defined(NO_PREFETCH)

#  define PREFETCH_L1(ptr)  (void)(ptr)  /* disabled */

#  define PREFETCH_L2(ptr)  (void)(ptr)  /* disabled */

#else

#  if defined(_MSC_VER) && (defined(_M_X64) || defined(_M_I86))  /* _mm_prefetch() is not defined outside of x86/x64 */

#    include <mmintrin.h>   /* https://msdn.microsoft.com/fr-fr/library/84szxsww(v=vs.90).aspx */

#    define PREFETCH_L1(ptr)  _mm_prefetch((const char*)(ptr), _MM_HINT_T0)

#    define PREFETCH_L2(ptr)  _mm_prefetch((const char*)(ptr), _MM_HINT_T1)

#  elif defined(__GNUC__) && ( (__GNUC__ >= 4) || ( (__GNUC__ == 3) && (__GNUC_MINOR__ >= 1) ) )

#    define PREFETCH_L1(ptr)  __builtin_prefetch((ptr), 0 /* rw==read */, 3 /* locality */)

#    define PREFETCH_L2(ptr)  __builtin_prefetch((ptr), 0 /* rw==read */, 2 /* locality */)

#  else

#    define PREFETCH_L1(ptr) (void)(ptr)  /* disabled */

#    define PREFETCH_L2(ptr) (void)(ptr)  /* disabled */

#  endif

#endif  /* NO_PREFETCH */

#define CACHELINE_SIZE 64

#define PREFETCH_AREA(p, s)  {            \

    const char* const _ptr = (const char*)(p);  \

    size_t const _size = (size_t)(s);     \

    size_t _pos;                          \

    for (_pos=0; _pos<_size; _pos+=CACHELINE_SIZE) {  \

        PREFETCH_L2(_ptr + _pos);         \

    }                                     \

}

/* vectorization

 * older GCC (pre gcc-4.3 picked as the cutoff) uses a different syntax */

#if !defined(__clang__) && defined(__GNUC__)

#  if (__GNUC__ == 4 && __GNUC_MINOR__ > 3) || (__GNUC__ >= 5)

#    define DONT_VECTORIZE __attribute__((optimize("no-tree-vectorize")))

#  else

#    define DONT_VECTORIZE _Pragma("GCC optimize(\"no-tree-vectorize\")")

#  endif

#else

#  define DONT_VECTORIZE

#endif

/* disable warnings */

#ifdef _MSC_VER    /* Visual Studio */

#  include <intrin.h>                    /* For Visual 2005 */

#  pragma warning(disable : 4100)        /* disable: C4100: unreferenced formal parameter */

#  pragma warning(disable : 4127)        /* disable: C4127: conditional expression is constant */

#  pragma warning(disable : 4204)        /* disable: C4204: non-constant aggregate initializer */

#  pragma warning(disable : 4214)        /* disable: C4214: non-int bitfields */

#  pragma warning(disable : 4324)        /* disable: C4324: padded structure */

#endif

#endif /* ZSTD_COMPILER_H */