Training courses

Kernel and Embedded Linux

Bootlin training courses

Embedded Linux, kernel,
Yocto Project, Buildroot, real-time,
graphics, boot time, debugging...

Bootlin logo

Elixir Cross Referencer

Open Menu /external/apache2/llvm/dist/libcxx/include/__bits 
  1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
// -*- C++ -*-
//===----------------------------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//

#ifndef _LIBCPP___BITS
#define _LIBCPP___BITS

#include <__config>

#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
#pragma GCC system_header
#endif

_LIBCPP_PUSH_MACROS
#include <__undef_macros>


_LIBCPP_BEGIN_NAMESPACE_STD

#ifndef _LIBCPP_COMPILER_MSVC

inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
int __libcpp_ctz(unsigned __x)           _NOEXCEPT { return __builtin_ctz(__x); }

inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
int __libcpp_ctz(unsigned long __x)      _NOEXCEPT { return __builtin_ctzl(__x); }

inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
int __libcpp_ctz(unsigned long long __x) _NOEXCEPT { return __builtin_ctzll(__x); }


inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
int __libcpp_clz(unsigned __x)           _NOEXCEPT { return __builtin_clz(__x); }

inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
int __libcpp_clz(unsigned long __x)      _NOEXCEPT { return __builtin_clzl(__x); }

inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
int __libcpp_clz(unsigned long long __x) _NOEXCEPT { return __builtin_clzll(__x); }


inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
int __libcpp_popcount(unsigned __x)           _NOEXCEPT { return __builtin_popcount(__x); }

inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
int __libcpp_popcount(unsigned long __x)      _NOEXCEPT { return __builtin_popcountl(__x); }

inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
int __libcpp_popcount(unsigned long long __x) _NOEXCEPT { return __builtin_popcountll(__x); }

#else  // _LIBCPP_COMPILER_MSVC

// Precondition:  __x != 0
inline _LIBCPP_INLINE_VISIBILITY
int __libcpp_ctz(unsigned __x) {
  static_assert(sizeof(unsigned) == sizeof(unsigned long), "");
  static_assert(sizeof(unsigned long) == 4, "");
  unsigned long __where;
  if (_BitScanForward(&__where, __x))
    return static_cast<int>(__where);
  return 32;
}

inline _LIBCPP_INLINE_VISIBILITY
int __libcpp_ctz(unsigned long __x) {
    static_assert(sizeof(unsigned long) == sizeof(unsigned), "");
    return __ctz(static_cast<unsigned>(__x));
}

inline _LIBCPP_INLINE_VISIBILITY
int __libcpp_ctz(unsigned long long __x) {
    unsigned long __where;
#if defined(_LIBCPP_HAS_BITSCAN64)
  if (_BitScanForward64(&__where, __x))
    return static_cast<int>(__where);
#else
  // Win32 doesn't have _BitScanForward64 so emulate it with two 32 bit calls.
  if (_BitScanForward(&__where, static_cast<unsigned long>(__x)))
    return static_cast<int>(__where);
  if (_BitScanForward(&__where, static_cast<unsigned long>(__x >> 32)))
    return static_cast<int>(__where + 32);
#endif
  return 64;
}

// Precondition:  __x != 0
inline _LIBCPP_INLINE_VISIBILITY
int __libcpp_clz(unsigned __x) {
  static_assert(sizeof(unsigned) == sizeof(unsigned long), "");
  static_assert(sizeof(unsigned long) == 4, "");
  unsigned long __where;
  if (_BitScanReverse(&__where, __x))
    return static_cast<int>(31 - __where);
  return 32; // Undefined Behavior.
}

inline _LIBCPP_INLINE_VISIBILITY
int __libcpp_clz(unsigned long __x) {
    static_assert(sizeof(unsigned) == sizeof(unsigned long), "");
    return __libcpp_clz(static_cast<unsigned>(__x));
}

inline _LIBCPP_INLINE_VISIBILITY
int __libcpp_clz(unsigned long long __x) {
  unsigned long __where;
#if defined(_LIBCPP_HAS_BITSCAN64)
  if (_BitScanReverse64(&__where, __x))
    return static_cast<int>(63 - __where);
#else
  // Win32 doesn't have _BitScanReverse64 so emulate it with two 32 bit calls.
  if (_BitScanReverse(&__where, static_cast<unsigned long>(__x >> 32)))
    return static_cast<int>(63 - (__where + 32));
  if (_BitScanReverse(&__where, static_cast<unsigned long>(__x)))
    return static_cast<int>(63 - __where);
#endif
  return 64; // Undefined Behavior.
}

inline _LIBCPP_INLINE_VISIBILITY int __libcpp_popcount(unsigned __x) {
  static_assert(sizeof(unsigned) == 4, "");
  return __popcnt(__x);
}

inline _LIBCPP_INLINE_VISIBILITY int __libcpp_popcount(unsigned long __x) {
  static_assert(sizeof(unsigned long) == 4, "");
  return __popcnt(__x);
}

inline _LIBCPP_INLINE_VISIBILITY int __libcpp_popcount(unsigned long long __x) {
  static_assert(sizeof(unsigned long long) == 8, "");
  return __popcnt64(__x);
}

#endif // _LIBCPP_COMPILER_MSVC

_LIBCPP_END_NAMESPACE_STD

_LIBCPP_POP_MACROS

#endif // _LIBCPP___BITS