159 lines
4.3 KiB
C++
159 lines
4.3 KiB
C++
// -*- C++ -*-
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//===------------------------------ bit ----------------------------------===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is dual licensed under the MIT and the University of Illinois Open
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// Source Licenses. See LICENSE.TXT for details.
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//
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//===---------------------------------------------------------------------===//
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#ifndef _LIBCPP_BIT
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#define _LIBCPP_BIT
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/*
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bit synopsis
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namespace std {
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} // namespace std
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*/
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#include <__config>
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#include <version>
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#if defined(__IBMCPP__)
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#include "support/ibm/support.h"
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#endif
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#if defined(_LIBCPP_COMPILER_MSVC)
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#include <intrin.h>
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#endif
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#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
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#pragma GCC system_header
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#endif
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_LIBCPP_BEGIN_NAMESPACE_STD
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#ifndef _LIBCPP_COMPILER_MSVC
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inline _LIBCPP_INLINE_VISIBILITY
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int __ctz(unsigned __x) { return __builtin_ctz(__x); }
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inline _LIBCPP_INLINE_VISIBILITY
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int __ctz(unsigned long __x) { return __builtin_ctzl(__x); }
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inline _LIBCPP_INLINE_VISIBILITY
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int __ctz(unsigned long long __x) { return __builtin_ctzll(__x); }
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inline _LIBCPP_INLINE_VISIBILITY
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int __clz(unsigned __x) { return __builtin_clz(__x); }
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inline _LIBCPP_INLINE_VISIBILITY
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int __clz(unsigned long __x) { return __builtin_clzl(__x); }
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inline _LIBCPP_INLINE_VISIBILITY
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int __clz(unsigned long long __x) { return __builtin_clzll(__x); }
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inline _LIBCPP_INLINE_VISIBILITY
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int __popcount(unsigned __x) { return __builtin_popcount(__x); }
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inline _LIBCPP_INLINE_VISIBILITY
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int __popcount(unsigned long __x) { return __builtin_popcountl(__x); }
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inline _LIBCPP_INLINE_VISIBILITY
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int __popcount(unsigned long long __x) { return __builtin_popcountll(__x); }
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#else // _LIBCPP_COMPILER_MSVC
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// Precondition: __x != 0
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inline _LIBCPP_INLINE_VISIBILITY
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int __ctz(unsigned __x) {
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static_assert(sizeof(unsigned) == sizeof(unsigned long), "");
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static_assert(sizeof(unsigned long) == 4, "");
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unsigned long __where;
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if (_BitScanForward(&__where, __x))
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return static_cast<int>(__where);
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return 32;
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}
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inline _LIBCPP_INLINE_VISIBILITY
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int __ctz(unsigned long __x) {
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static_assert(sizeof(unsigned long) == sizeof(unsigned), "");
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return __ctz(static_cast<unsigned>(__x));
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}
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inline _LIBCPP_INLINE_VISIBILITY
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int __ctz(unsigned long long __x) {
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unsigned long __where;
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#if defined(_LIBCPP_HAS_BITSCAN64)
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(defined(_M_AMD64) || defined(__x86_64__))
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if (_BitScanForward64(&__where, __x))
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return static_cast<int>(__where);
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#else
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// Win32 doesn't have _BitScanForward64 so emulate it with two 32 bit calls.
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if (_BitScanForward(&__where, static_cast<unsigned long>(__x)))
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return static_cast<int>(__where);
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if (_BitScanForward(&__where, static_cast<unsigned long>(__x >> 32)))
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return static_cast<int>(__where + 32);
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#endif
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return 64;
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}
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// Precondition: __x != 0
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inline _LIBCPP_INLINE_VISIBILITY
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int __clz(unsigned __x) {
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static_assert(sizeof(unsigned) == sizeof(unsigned long), "");
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static_assert(sizeof(unsigned long) == 4, "");
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unsigned long __where;
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if (_BitScanReverse(&__where, __x))
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return static_cast<int>(31 - __where);
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return 32; // Undefined Behavior.
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}
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inline _LIBCPP_INLINE_VISIBILITY
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int __clz(unsigned long __x) {
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static_assert(sizeof(unsigned) == sizeof(unsigned long), "");
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return __clz(static_cast<unsigned>(__x));
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}
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inline _LIBCPP_INLINE_VISIBILITY
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int __clz(unsigned long long __x) {
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unsigned long __where;
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#if defined(_LIBCPP_HAS_BITSCAN64)
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if (_BitScanReverse64(&__where, __x))
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return static_cast<int>(63 - __where);
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#else
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// Win32 doesn't have _BitScanReverse64 so emulate it with two 32 bit calls.
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if (_BitScanReverse(&__where, static_cast<unsigned long>(__x >> 32)))
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return static_cast<int>(63 - (__where + 32));
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if (_BitScanReverse(&__where, static_cast<unsigned long>(__x)))
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return static_cast<int>(63 - __where);
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#endif
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return 64; // Undefined Behavior.
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}
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inline _LIBCPP_INLINE_VISIBILITY int __popcount(unsigned __x) {
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static_assert(sizeof(unsigned) == 4, "");
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return __popcnt(__x);
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}
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inline _LIBCPP_INLINE_VISIBILITY int __popcount(unsigned long __x) {
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static_assert(sizeof(unsigned long) == 4, "");
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return __popcnt(__x);
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}
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inline _LIBCPP_INLINE_VISIBILITY int __popcount(unsigned long long __x) {
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static_assert(sizeof(unsigned long long) == 8, "");
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return __popcnt64(__x);
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}
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#endif // _LIBCPP_COMPILER_MSVC
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_LIBCPP_END_NAMESPACE_STD
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#endif // _LIBCPP_BIT
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