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construct/include/ircd/fpe.h
2022-06-17 21:11:53 -07:00

136 lines
2.7 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_FPE_H
namespace ircd::fpe
{
struct errors_handle;
struct scope_round;
template<class T>
string_view classify(const T &) noexcept;
string_view reflect_sicode(const int &) noexcept;
string_view reflect(const ushort &flag) noexcept;
string_view reflect(const mutable_buffer &, const ushort &flags);
[[noreturn]] void _throw_errors(const ushort &flags);
void throw_errors(const ushort &flags);
void set_round(const std::float_round_style &style);
std::fexcept_t set_excepts(const ushort &flag);
void debug_info();
}
/// scope_round
///
struct ircd::fpe::scope_round
{
int theirs
{
std::fegetround()
};
scope_round(const std::float_round_style &ours) noexcept
{
std::fesetround(ours);
}
scope_round(const scope_round &) = delete;
scope_round &operator=(const scope_round &) = delete;
~scope_round() noexcept
{
std::fesetround(theirs);
}
};
/// errors_handle
///
/// Perform a single floating point operation at a time within the scope
/// of fpe::errors_handle. After each operation check the floating point
/// unit for an error status flag and throw a C++ exception.
struct ircd::fpe::errors_handle
{
std::fexcept_t theirs;
public:
ushort pending() const;
void throw_pending() const;
void clear_pending();
errors_handle();
~errors_handle() noexcept(false);
};
[[gnu::always_inline]] inline
ircd::fpe::errors_handle::errors_handle()
{
syscall(std::fegetexceptflag, &theirs, FE_ALL_EXCEPT);
clear_pending();
}
[[gnu::always_inline]] inline
ircd::fpe::errors_handle::~errors_handle()
noexcept(false)
{
const unwind reset{[this]
{
syscall(std::fesetexceptflag, &theirs, FE_ALL_EXCEPT);
}};
throw_pending();
}
inline void
ircd::fpe::errors_handle::clear_pending()
{
syscall(std::feclearexcept, FE_ALL_EXCEPT);
}
inline void
ircd::fpe::errors_handle::throw_pending()
const
{
const auto pending
{
this->pending()
};
if(unlikely(pending))
_throw_errors(pending);
}
inline ushort
ircd::fpe::errors_handle::pending()
const
{
return std::fetestexcept(FE_ALL_EXCEPT);
}
//
// ircd::fpe
//
inline std::fexcept_t
ircd::fpe::set_excepts(const ushort &flags)
{
std::fexcept_t theirs;
syscall(std::fesetexceptflag, &theirs, flags);
return theirs;
}
inline void
ircd::fpe::set_round(const std::float_round_style &style)
{
syscall(std::fesetround, style);
}