| // -*- C++ -*- |
| //===------------------------------ bit ----------------------------------===// |
| // |
| // 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_BIT |
| #define _LIBCPP_BIT |
| |
| /* |
| bit synopsis |
| |
| namespace std { |
| |
| } // namespace std |
| |
| */ |
| |
| #include <__config> |
| #include <version> |
| |
| #if defined(__IBMCPP__) |
| #include "support/ibm/support.h" |
| #endif |
| #if defined(_LIBCPP_COMPILER_MSVC) |
| #include <intrin.h> |
| #endif |
| |
| #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) |
| #pragma GCC system_header |
| #endif |
| |
| _LIBCPP_BEGIN_NAMESPACE_STD |
| |
| #ifndef _LIBCPP_COMPILER_MSVC |
| |
| inline _LIBCPP_INLINE_VISIBILITY |
| int __ctz(unsigned __x) { return __builtin_ctz(__x); } |
| |
| inline _LIBCPP_INLINE_VISIBILITY |
| int __ctz(unsigned long __x) { return __builtin_ctzl(__x); } |
| |
| inline _LIBCPP_INLINE_VISIBILITY |
| int __ctz(unsigned long long __x) { return __builtin_ctzll(__x); } |
| |
| |
| inline _LIBCPP_INLINE_VISIBILITY |
| int __clz(unsigned __x) { return __builtin_clz(__x); } |
| |
| inline _LIBCPP_INLINE_VISIBILITY |
| int __clz(unsigned long __x) { return __builtin_clzl(__x); } |
| |
| inline _LIBCPP_INLINE_VISIBILITY |
| int __clz(unsigned long long __x) { return __builtin_clzll(__x); } |
| |
| |
| inline _LIBCPP_INLINE_VISIBILITY |
| int __popcount(unsigned __x) { return __builtin_popcount(__x); } |
| |
| inline _LIBCPP_INLINE_VISIBILITY |
| int __popcount(unsigned long __x) { return __builtin_popcountl(__x); } |
| |
| inline _LIBCPP_INLINE_VISIBILITY |
| int __popcount(unsigned long long __x) { return __builtin_popcountll(__x); } |
| |
| #else // _LIBCPP_COMPILER_MSVC |
| |
| // Precondition: __x != 0 |
| inline _LIBCPP_INLINE_VISIBILITY |
| int __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 __ctz(unsigned long __x) { |
| static_assert(sizeof(unsigned long) == sizeof(unsigned), ""); |
| return __ctz(static_cast<unsigned>(__x)); |
| } |
| |
| inline _LIBCPP_INLINE_VISIBILITY |
| int __ctz(unsigned long long __x) { |
| unsigned long __where; |
| #if defined(_LIBCPP_HAS_BITSCAN64) |
| (defined(_M_AMD64) || defined(__x86_64__)) |
| 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 __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 __clz(unsigned long __x) { |
| static_assert(sizeof(unsigned) == sizeof(unsigned long), ""); |
| return __clz(static_cast<unsigned>(__x)); |
| } |
| |
| inline _LIBCPP_INLINE_VISIBILITY |
| int __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 __popcount(unsigned __x) { |
| static_assert(sizeof(unsigned) == 4, ""); |
| return __popcnt(__x); |
| } |
| |
| inline _LIBCPP_INLINE_VISIBILITY int __popcount(unsigned long __x) { |
| static_assert(sizeof(unsigned long) == 4, ""); |
| return __popcnt(__x); |
| } |
| |
| inline _LIBCPP_INLINE_VISIBILITY int __popcount(unsigned long long __x) { |
| static_assert(sizeof(unsigned long long) == 8, ""); |
| return __popcnt64(__x); |
| } |
| |
| #endif // _LIBCPP_COMPILER_MSVC |
| |
| _LIBCPP_END_NAMESPACE_STD |
| |
| #endif // _LIBCPP_BIT |