mirror of
https://github.com/matrix-construct/construct
synced 2024-07-03 17:28:18 +02:00
62 lines
1.6 KiB
C++
62 lines
1.6 KiB
C++
// The Construct
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//
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// Copyright (C) The Construct Developers, Authors & Contributors
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// Copyright (C) 2016-2020 Jason Volk <jason@zemos.net>
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//
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// Permission to use, copy, modify, and/or distribute this software for any
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// purpose with or without fee is hereby granted, provided that the above
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// copyright notice and this permission notice is present in all copies. The
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// full license for this software is available in the LICENSE file.
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#pragma once
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#define HAVE_IRCD_SIMD_POPCNT_H
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namespace ircd::simd
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{
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template<class T> T popmask(const T) noexcept;
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template<class T> T boolmask(const T) noexcept;
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template<class T> uint popcnt(const T) noexcept;
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}
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/// Convenience template. Unfortunately this drops to scalar until specific
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/// targets and specializations are created.
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template<class T>
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inline uint
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ircd::simd::popcnt(const T a)
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noexcept
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{
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uint ret(0), i(0);
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for(; i < lanes<T>(); ++i)
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if constexpr(sizeof_lane<T>() <= sizeof(int))
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ret += __builtin_popcount(a[i]);
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else if constexpr(sizeof_lane<T>() <= sizeof(long))
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ret += __builtin_popcountl(a[i]);
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else
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ret += __builtin_popcountll(a[i]);
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return ret;
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}
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/// Convenience template. Extends a bool value where the lsb is 1 or 0 into a
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/// mask value like the result of vector comparisons.
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template<class T>
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[[gnu::always_inline]]
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inline T
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ircd::simd::boolmask(const T a)
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noexcept
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{
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return ~(popmask(a) - 1);
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}
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/// Convenience template. Vector compare instructions yield 0xff on equal;
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/// sometimes one might need an actual value of 1 for accumulators or maybe
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/// some bool-type reason...
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template<class T>
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[[gnu::always_inline]]
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inline T
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ircd::simd::popmask(const T a)
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noexcept
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{
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return a & 1;
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}
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