1 // -*- C++ -*- 2 //===----------------------- support/win32/support.h ----------------------===// 3 // 4 // The LLVM Compiler Infrastructure 5 // 6 // This file is dual licensed under the MIT and the University of Illinois Open 7 // Source Licenses. See LICENSE.TXT for details. 8 // 9 //===----------------------------------------------------------------------===// 10 11 #ifndef _LIBCPP_SUPPORT_WIN32_SUPPORT_H 12 #define _LIBCPP_SUPPORT_WIN32_SUPPORT_H 13 14 // Functions and constants used in libc++ that 15 // are missing from the Windows C library. 16 17 #include <wchar.h> // mbstate_t 18 #include <cstdarg> // va_ macros 19 // "builtins" not implemented here for Clang or GCC as they provide 20 // implementations. Assuming required for elsewhere else, certainly MSVC. 21 #if defined(_LIBCPP_MSVC) 22 #include <intrin.h> 23 #endif 24 #if defined(_LIBCPP_MSVCRT) 25 #include <xlocinfo.h> 26 #endif 27 #define swprintf _snwprintf 28 #define vswprintf _vsnwprintf 29 30 #ifndef NOMINMAX 31 #define NOMINMAX 32 #endif 33 34 extern "C" { 35 36 int vasprintf(char **sptr, const char *__restrict fmt, va_list ap); 37 int asprintf(char **sptr, const char *__restrict fmt, ...); 38 size_t mbsnrtowcs(wchar_t *__restrict dst, const char **__restrict src, 39 size_t nmc, size_t len, mbstate_t *__restrict ps); 40 size_t wcsnrtombs(char *__restrict dst, const wchar_t **__restrict src, 41 size_t nwc, size_t len, mbstate_t *__restrict ps); 42 } 43 44 #if defined(_LIBCPP_MSVCRT) 45 #define snprintf _snprintf 46 #define atoll _atoi64 47 #define strtoll _strtoi64 48 #define strtoull _strtoui64 49 #define wcstoll _wcstoi64 50 #define wcstoull _wcstoui64 51 _LIBCPP_ALWAYS_INLINE float strtof(const char *nptr, char **endptr) 52 { 53 return _Stof(nptr, endptr, 0); 54 } 55 _LIBCPP_ALWAYS_INLINE double strtod(const char *nptr, char **endptr) 56 { 57 return _Stod(nptr, endptr, 0); 58 } 59 _LIBCPP_ALWAYS_INLINE long double strtold(const char *nptr, char **endptr) 60 { 61 return _Stold(nptr, endptr, 0); 62 } 63 64 #define _Exit _exit 65 #endif 66 67 #if defined(_LIBCPP_MSVC) 68 69 // Bit builtin's make these assumptions when calling _BitScanForward/Reverse 70 // etc. These assumptions are expected to be true for Win32/Win64 which this 71 // file supports. 72 static_assert(sizeof(unsigned long long) == 8, ""); 73 static_assert(sizeof(unsigned long) == 4, ""); 74 static_assert(sizeof(unsigned int) == 4, ""); 75 76 _LIBCPP_ALWAYS_INLINE int __builtin_popcount(unsigned int x) 77 { 78 // Binary: 0101... 79 static const unsigned int m1 = 0x55555555; 80 // Binary: 00110011.. 81 static const unsigned int m2 = 0x33333333; 82 // Binary: 4 zeros, 4 ones ... 83 static const unsigned int m4 = 0x0f0f0f0f; 84 // The sum of 256 to the power of 0,1,2,3... 85 static const unsigned int h01 = 0x01010101; 86 // Put count of each 2 bits into those 2 bits. 87 x -= (x >> 1) & m1; 88 // Put count of each 4 bits into those 4 bits. 89 x = (x & m2) + ((x >> 2) & m2); 90 // Put count of each 8 bits into those 8 bits. 91 x = (x + (x >> 4)) & m4; 92 // Returns left 8 bits of x + (x<<8) + (x<<16) + (x<<24). 93 return (x * h01) >> 24; 94 } 95 96 _LIBCPP_ALWAYS_INLINE int __builtin_popcountl(unsigned long x) 97 { 98 return __builtin_popcount(static_cast<int>(x)); 99 } 100 101 _LIBCPP_ALWAYS_INLINE int __builtin_popcountll(unsigned long long x) 102 { 103 // Binary: 0101... 104 static const unsigned long long m1 = 0x5555555555555555; 105 // Binary: 00110011.. 106 static const unsigned long long m2 = 0x3333333333333333; 107 // Binary: 4 zeros, 4 ones ... 108 static const unsigned long long m4 = 0x0f0f0f0f0f0f0f0f; 109 // The sum of 256 to the power of 0,1,2,3... 110 static const unsigned long long h01 = 0x0101010101010101; 111 // Put count of each 2 bits into those 2 bits. 112 x -= (x >> 1) & m1; 113 // Put count of each 4 bits into those 4 bits. 114 x = (x & m2) + ((x >> 2) & m2); 115 // Put count of each 8 bits into those 8 bits. 116 x = (x + (x >> 4)) & m4; 117 // Returns left 8 bits of x + (x<<8) + (x<<16) + (x<<24) + ... 118 return static_cast<int>((x * h01) >> 56); 119 } 120 121 // Returns the number of trailing 0-bits in x, starting at the least significant 122 // bit position. If x is 0, the result is undefined. 123 _LIBCPP_ALWAYS_INLINE int __builtin_ctzll(unsigned long long mask) 124 { 125 unsigned long where; 126 // Search from LSB to MSB for first set bit. 127 // Returns zero if no set bit is found. 128 #if defined(_WIN64) 129 if (_BitScanForward64(&where, mask)) 130 return static_cast<int>(where); 131 #elif defined(_WIN32) 132 // Win32 doesn't have _BitScanForward64 so emulate it with two 32 bit calls. 133 // Scan the Low Word. 134 if (_BitScanForward(&where, static_cast<unsigned long>(mask))) 135 return static_cast<int>(where); 136 // Scan the High Word. 137 if (_BitScanForward(&where, static_cast<unsigned long>(mask >> 32))) 138 return static_cast<int>(where + 32); // Create a bit offset from the LSB. 139 #else 140 #error "Implementation of __builtin_ctzll required" 141 #endif 142 return 64; 143 } 144 145 _LIBCPP_ALWAYS_INLINE int __builtin_ctzl(unsigned long mask) 146 { 147 unsigned long where; 148 // Search from LSB to MSB for first set bit. 149 // Returns zero if no set bit is found. 150 if (_BitScanForward(&where, mask)) 151 return static_cast<int>(where); 152 return 32; 153 } 154 155 _LIBCPP_ALWAYS_INLINE int __builtin_ctz(unsigned int mask) 156 { 157 // Win32 and Win64 expectations. 158 static_assert(sizeof(mask) == 4, ""); 159 static_assert(sizeof(unsigned long) == 4, ""); 160 return __builtin_ctzl(static_cast<unsigned long>(mask)); 161 } 162 163 // Returns the number of leading 0-bits in x, starting at the most significant 164 // bit position. If x is 0, the result is undefined. 165 _LIBCPP_ALWAYS_INLINE int __builtin_clzll(unsigned long long mask) 166 { 167 unsigned long where; 168 // BitScanReverse scans from MSB to LSB for first set bit. 169 // Returns 0 if no set bit is found. 170 #if defined(_WIN64) 171 if (_BitScanReverse64(&where, mask)) 172 return static_cast<int>(63 - where); 173 #elif defined(_WIN32) 174 // Scan the high 32 bits. 175 if (_BitScanReverse(&where, static_cast<unsigned long>(mask >> 32))) 176 return static_cast<int>(63 - 177 (where + 32)); // Create a bit offset from the MSB. 178 // Scan the low 32 bits. 179 if (_BitScanReverse(&where, static_cast<unsigned long>(mask))) 180 return static_cast<int>(63 - where); 181 #else 182 #error "Implementation of __builtin_clzll required" 183 #endif 184 return 64; // Undefined Behavior. 185 } 186 187 _LIBCPP_ALWAYS_INLINE int __builtin_clzl(unsigned long mask) 188 { 189 unsigned long where; 190 // Search from LSB to MSB for first set bit. 191 // Returns zero if no set bit is found. 192 if (_BitScanReverse(&where, mask)) 193 return static_cast<int>(31 - where); 194 return 32; // Undefined Behavior. 195 } 196 197 _LIBCPP_ALWAYS_INLINE int __builtin_clz(unsigned int x) 198 { 199 return __builtin_clzl(x); 200 } 201 #endif // _LIBCPP_MSVC 202 203 #endif // _LIBCPP_SUPPORT_WIN32_SUPPORT_H 204
