1
0
Fork 0
mirror of https://gitlab.com/sortix/sortix.git synced 2023-02-13 20:55:38 -05:00
sortix--sortix/kernel/x86-family/float.cpp
2014-03-01 14:37:39 +01:00

88 lines
2.1 KiB
C++

/*******************************************************************************
Copyright(C) Jonas 'Sortie' Termansen 2011, 2012.
This file is part of Sortix.
Sortix 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 of the License, or (at your option) any later
version.
Sortix 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.
You should have received a copy of the GNU General Public License along with
Sortix. If not, see <http://www.gnu.org/licenses/>.
x86-family/float.cpp
Handles saving and restoration of floating point numbers.
*******************************************************************************/
#include <assert.h>
#include <sortix/kernel/interrupt.h>
#include <sortix/kernel/kernel.h>
#include <sortix/kernel/thread.h>
#include "float.h"
namespace Sortix {
namespace Float {
static Thread* fputhread;
static inline void InitFPU()
{
asm volatile ("fninit");
}
static inline void SaveState(uint8_t* dest)
{
assert( (((unsigned long) dest) & (16UL-1UL)) == 0 );
asm volatile ("fxsave (%0)" : : "r"(dest));
}
static inline void LoadState(const uint8_t* src)
{
assert( (((unsigned long) src) & (16UL-1UL)) == 0 );
asm volatile ("fxrstor (%0)" : : "r"(src));
}
static void OnFPUAccess(CPU::InterruptRegisters* /*regs*/, void* /*user*/)
{
EnableFPU();
Thread* thread = CurrentThread();
if ( thread == fputhread )
return;
if ( fputhread )
SaveState(fputhread->fpuenvaligned);
fputhread = thread;
if ( !thread->fpuinitialized )
{
InitFPU();
thread->fpuinitialized = true;
return;
}
LoadState(thread->fpuenvaligned);
}
void Init()
{
fputhread = CurrentThread();
assert(fputhread);
Interrupt::RegisterHandler(7, OnFPUAccess, NULL);
}
void NofityTaskExit(Thread* thread)
{
if ( fputhread == thread )
fputhread = NULL;
DisableFPU();
}
} // namespace Float
} // namespace Sortix