simd_ppc.h
// Simd PowerPC specific implementations -*- C++ -*-
// Copyright (C) 2020-2026 Free Software Foundation, Inc.
//
// This file is part of the GNU ISO C++ Library. This library is free
// software; you can redistribute it and/or modify it under the
// terms of the GNU General Public License as published by the
// Free Software Foundation; either version 3, or (at your option)
// any later version.
// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
// Under Section 7 of GPL version 3, you are granted additional
// permissions described in the GCC Runtime Library Exception, version
// 3.1, as published by the Free Software Foundation.
// You should have received a copy of the GNU General Public License and
// a copy of the GCC Runtime Library Exception along with this program;
// see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
// <http://www.gnu.org/licenses/>.
#ifndef _GLIBCXX_EXPERIMENTAL_SIMD_PPC_H_
#define _GLIBCXX_EXPERIMENTAL_SIMD_PPC_H_
#if __cplusplus >= 201703L
#ifndef __ALTIVEC__
#error "simd_ppc.h may only be included when AltiVec/VMX is available"
#endif
#include <altivec.h>
_GLIBCXX_SIMD_BEGIN_NAMESPACE
// _SimdImplPpc {{{
template <typename _Abi, typename>
struct _SimdImplPpc : _SimdImplBuiltin<_Abi>
{
using _Base = _SimdImplBuiltin<_Abi>;
// Byte and halfword shift instructions on PPC only consider the low 3 or 4
// bits of the RHS. Consequently, shifting by sizeof(_Tp)*CHAR_BIT (or more)
// is UB without extra measures. To match scalar behavior, byte and halfword
// shifts need an extra fixup step.
// _S_bit_shift_left {{{
template <typename _Tp, size_t _Np>
_GLIBCXX_SIMD_INTRINSIC static constexpr _SimdWrapper<_Tp, _Np>
_S_bit_shift_left(_SimdWrapper<_Tp, _Np> __x, _SimdWrapper<_Tp, _Np> __y)
{
__x = _Base::_S_bit_shift_left(__x, __y);
if constexpr (sizeof(_Tp) < sizeof(int))
__x._M_data
= (__y._M_data < sizeof(_Tp) * __CHAR_BIT__) & __x._M_data;
return __x;
}
template <typename _Tp, size_t _Np>
_GLIBCXX_SIMD_INTRINSIC static constexpr _SimdWrapper<_Tp, _Np>
_S_bit_shift_left(_SimdWrapper<_Tp, _Np> __x, int __y)
{
__x = _Base::_S_bit_shift_left(__x, __y);
if constexpr (sizeof(_Tp) < sizeof(int))
{
if (__y >= int(sizeof(_Tp) * __CHAR_BIT__))
return {};
}
return __x;
}
// }}}
// _S_bit_shift_right {{{
template <typename _Tp, size_t _Np>
_GLIBCXX_SIMD_INTRINSIC static constexpr _SimdWrapper<_Tp, _Np>
_S_bit_shift_right(_SimdWrapper<_Tp, _Np> __x, _SimdWrapper<_Tp, _Np> __y)
{
if constexpr (sizeof(_Tp) < sizeof(int))
{
constexpr int __nbits = sizeof(_Tp) * __CHAR_BIT__;
if constexpr (is_unsigned_v<_Tp>)
return (__y._M_data < __nbits)
& _Base::_S_bit_shift_right(__x, __y)._M_data;
else
{
_Base::_S_masked_assign(_SimdWrapper<_Tp, _Np>(__y._M_data
>= __nbits),
__y, __nbits - 1);
return _Base::_S_bit_shift_right(__x, __y);
}
}
else
return _Base::_S_bit_shift_right(__x, __y);
}
template <typename _Tp, size_t _Np>
_GLIBCXX_SIMD_INTRINSIC static constexpr _SimdWrapper<_Tp, _Np>
_S_bit_shift_right(_SimdWrapper<_Tp, _Np> __x, int __y)
{
if constexpr (sizeof(_Tp) < sizeof(int))
{
constexpr int __nbits = sizeof(_Tp) * __CHAR_BIT__;
if (__y >= __nbits)
{
if constexpr (is_unsigned_v<_Tp>)
return {};
else
return _Base::_S_bit_shift_right(__x, __nbits - 1);
}
}
return _Base::_S_bit_shift_right(__x, __y);
}
// }}}
};
// }}}
// _MaskImplPpc {{{
template <typename _Abi, typename>
struct _MaskImplPpc : _MaskImplBuiltin<_Abi>
{
using _Base = _MaskImplBuiltin<_Abi>;
// _S_popcount {{{
template <typename _Tp>
_GLIBCXX_SIMD_INTRINSIC static int
_S_popcount(simd_mask<_Tp, _Abi> __k)
{
const auto __kv = __as_vector(__k);
if constexpr (__have_power10vec)
{
using _Intrin = __intrinsic_type16_t<make_unsigned_t<__int_for_sizeof_t<_Tp>>>;
return vec_cntm(reinterpret_cast<_Intrin>(__kv), 1);
}
else if constexpr (sizeof(_Tp) >= sizeof(int))
{
using _Intrin = __intrinsic_type16_t<int>;
const int __sum = -vec_sums(__intrin_bitcast<_Intrin>(__kv), _Intrin())[3];
return __sum / (sizeof(_Tp) / sizeof(int));
}
else
{
const auto __summed_to_int = vec_sum4s(__to_intrin(__kv), __intrinsic_type16_t<int>());
return -vec_sums(__summed_to_int, __intrinsic_type16_t<int>())[3];
}
}
// }}}
};
// }}}
_GLIBCXX_SIMD_END_NAMESPACE
#endif // __cplusplus >= 201703L
#endif // _GLIBCXX_EXPERIMENTAL_SIMD_PPC_H_
// vim: foldmethod=marker foldmarker={{{,}}} sw=2 noet ts=8 sts=2 tw=100