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construct/include/ircd/simd/shr.h

133 lines
2.9 KiB
C++

// The Construct
//
// Copyright (C) The Construct Developers, Authors & Contributors
// Copyright (C) 2016-2020 Jason Volk <jason@zemos.net>
//
// Permission to use, copy, modify, and/or distribute this software for any
// purpose with or without fee is hereby granted, provided that the above
// copyright notice and this permission notice is present in all copies. The
// full license for this software is available in the LICENSE file.
#pragma once
#define HAVE_IRCD_SIMD_SHR_H
// xmmx shift-right interface
namespace ircd::simd
{
template<int b,
class V,
class T>
T _shr(const T) noexcept;
template<int b,
class T>
typename std::enable_if<sizeof(T) == 16, T>::type
shr(const T a) noexcept;
template<int b,
class T>
typename std::enable_if<sizeof(T) == 32, T>::type
shr(const T a) noexcept;
template<int b,
class T>
typename std::enable_if<sizeof(T) == 64, T>::type
shr(const T a) noexcept;
}
template<int b,
class V,
class T>
[[using gnu: always_inline, gnu_inline, artificial]]
extern inline T
ircd::simd::_shr(const T a)
noexcept
{
static_assert
(
sizeof(T) == sizeof(V)
);
static_assert
(
b % 8 == 0, "[emulated] xmmx register only shifts right at bytewise resolution."
);
constexpr int B
{
b / 8
};
V arg(a), ret(a);
for(size_t i(0); i < sizeof(V) - B; ++i)
ret[i] = arg[i + B];
for(size_t i(sizeof(V) - B); i < sizeof(V); ++i)
ret[i] = 0;
return T(ret);
}
#if defined(HAVE_X86INTRIN_H) && defined(__SSE2__)
template<int b,
class T>
[[using gnu: always_inline, gnu_inline, artificial]]
extern inline typename std::enable_if<sizeof(T) == 16, T>::type
ircd::simd::shr(const T a)
noexcept
{
static_assert
(
b % 8 == 0, "xmmx register only shifts right at bytewise resolution."
);
return T(_mm_bsrli_si128(u128x1(a), b / 8));
}
#else
template<int b,
class T>
[[using gnu: always_inline, gnu_inline, artificial]]
extern inline typename std::enable_if<sizeof(T) == 16, T>::type
ircd::simd::shr(const T a)
noexcept
{
return _shr<b, u8x16>(a);
}
#endif
#if defined(HAVE_X86INTRIN_H) && defined(__AVX2__)
template<int b,
class T>
[[using gnu: always_inline, gnu_inline, artificial]]
extern inline typename std::enable_if<sizeof(T) == 32, T>::type
ircd::simd::shr(const T a)
noexcept
{
static_assert
(
b % 8 == 0, "ymmx register only shifts right at bytewise resolution."
);
return T(_mm256_srli_si256(u256x1(a), b / 8));
}
#else
template<int b,
class T>
[[using gnu: always_inline, gnu_inline, artificial]]
extern inline typename std::enable_if<sizeof(T) == 32, T>::type
ircd::simd::shr(const T a)
noexcept
{
return _shr<b, u8x32>(a);
}
#endif
template<int b,
class T>
[[using gnu: always_inline, gnu_inline, artificial]]
extern inline typename std::enable_if<sizeof(T) == 64, T>::type
ircd::simd::shr(const T a)
noexcept
{
return _shr<b, u8x64>(a);
}