mirror of
https://github.com/RetroDECK/Duckstation.git
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63 lines
1.6 KiB
C++
63 lines
1.6 KiB
C++
#pragma once
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#include "types.h"
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#ifdef _MSC_VER
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#include <intrin.h>
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#endif
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template<typename T>
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ALWAYS_INLINE unsigned CountLeadingZeros(T value)
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{
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#ifdef _MSC_VER
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if constexpr (sizeof(value) >= sizeof(u64))
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{
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unsigned long index;
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return _BitScanReverse64(&index, ZeroExtend64(value)) ? static_cast<unsigned>(index) : 0;
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}
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else
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{
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unsigned long index;
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return _BitScanReverse(&index, ZeroExtend32(value)) ? static_cast<unsigned>(index) : 0;
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}
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#else
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if constexpr (sizeof(value) >= sizeof(u64))
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{
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const unsigned bits = static_cast<unsigned>(__builtin_clzl(ZeroExtend64(value)));
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return (value != 0) ? static_cast<unsigned>(bits) : 0;
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}
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else
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{
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const unsigned bits = static_cast<unsigned>(__builtin_clz(ZeroExtend32(value)));
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return (value != 0) ? static_cast<unsigned>(bits) : 0;
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}
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#endif
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}
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template<typename T>
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ALWAYS_INLINE unsigned CountTrailingZeros(T value)
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{
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#ifdef _MSC_VER
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if constexpr (sizeof(value) >= sizeof(u64))
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{
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unsigned long index;
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return _BitScanForward64(&index, ZeroExtend64(value)) ? static_cast<unsigned>(index) : 0;
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}
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else
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{
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unsigned long index;
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return _BitScanForward(&index, ZeroExtend32(value)) ? static_cast<unsigned>(index) : 0;
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}
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#else
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if constexpr (sizeof(value) >= sizeof(u64))
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{
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const unsigned bits = static_cast<unsigned>(__builtin_ctzl(ZeroExtend64(value)));
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return (value != 0) ? static_cast<unsigned>(bits) : 0;
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}
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else
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{
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const unsigned bits = static_cast<unsigned>(__builtin_ctz(ZeroExtend32(value)));
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return (value != 0) ? static_cast<unsigned>(bits) : 0;
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}
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#endif
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}
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