78002be334
* DSP: Own DSP RAM and add it to fastmem * Vendor Teakra * Add MacOS support to fastmem * Fix MacOS fastmem paths * Fix iOS build
27 lines
597 B
C++
27 lines
597 B
C++
#pragma once
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#include <limits>
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#include <type_traits>
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#ifdef _MSC_VER
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#include <intrin.h>
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#endif
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namespace std20 {
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// A simple (and not very correct) implementation of C++20's std::log2p1
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template <class T>
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constexpr T log2p1(T x) noexcept {
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static_assert(std::is_integral_v<T> && std::is_unsigned_v<T>);
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if (x == 0)
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return 0;
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#ifdef _MSC_VER
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unsigned long index = 0;
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_BitScanReverse64(&index, x);
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return static_cast<T>(index) + 1;
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#else
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return static_cast<T>(std::numeric_limits<unsigned long long>::digits - __builtin_clzll(x));
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#endif
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}
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} // namespace std20
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