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construct/include/ircd/simd/ror.h
2020-10-11 10:10:50 -07:00

105 lines
2.1 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_ROR_H
// xmmx rotate-right interface
namespace ircd::simd
{
template<int b,
class V,
class T>
T _ror(const T) noexcept;
template<int b,
class T>
typename std::enable_if<sizeof(T) == 16, T>::type
ror(const T a) noexcept;
template<int b,
class T>
typename std::enable_if<sizeof(T) == 32, T>::type
ror(const T a) noexcept;
template<int b,
class T>
typename std::enable_if<sizeof(T) == 64, T>::type
ror(const T a) noexcept;
}
template<int b,
class V,
class T>
[[using gnu: always_inline, gnu_inline, artificial]]
extern inline T
ircd::simd::_ror(const T a)
noexcept
{
static_assert
(
sizeof(T) == sizeof(V)
);
static_assert
(
b % 8 == 0, "[emulated] xmmx register only rotates left at bytewise resolution."
);
constexpr int B
{
b / 8
};
constexpr auto S
{
sizeof(V) - B
};
size_t i(0);
V arg(a), ret;
for(; i < S; ++i)
ret[i] = arg[i + B];
for(; i < sizeof(V); ++i)
ret[i] = arg[i - S];
return T(ret);
}
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::ror(const T a)
noexcept
{
return _ror<b, u8x16>(a);
}
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::ror(const T a)
noexcept
{
return _ror<b, u8x32>(a);
}
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::ror(const T a)
noexcept
{
return _ror<b, u8x64>(a);
}