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/*
* linux/arch/i386/kernel/i387.c
*
* Copyright (C) 1994 Linus Torvalds
*
* Pentium III FXSR, SSE support
* General FPU state handling cleanups
* Gareth Hughes <gareth@valinux.com>, May 2000
*/
#include <xeno/config.h>
#include <xeno/sched.h>
#include <asm/processor.h>
#include <asm/i387.h>
void init_fpu(void)
{
__asm__("fninit");
if ( cpu_has_xmm ) load_mxcsr(0x1f80);
current->flags |= PF_DONEFPUINIT;
}
static inline void __save_init_fpu( struct task_struct *tsk )
{
if ( cpu_has_fxsr ) {
asm volatile( "fxsave %0 ; fnclex"
: "=m" (tsk->thread.i387.fxsave) );
} else {
asm volatile( "fnsave %0 ; fwait"
: "=m" (tsk->thread.i387.fsave) );
}
tsk->flags &= ~PF_USEDFPU;
}
void save_init_fpu( struct task_struct *tsk )
{
/*
* The guest OS may have set the 'virtual STTS' flag.
* This causes us to set the real flag, so we'll need
* to temporarily clear it while saving f-p state.
*/
if ( tsk->flags & PF_GUEST_STTS ) clts();
__save_init_fpu(tsk);
stts();
}
void restore_fpu( struct task_struct *tsk )
{
if ( cpu_has_fxsr ) {
asm volatile( "fxrstor %0"
: : "m" (tsk->thread.i387.fxsave) );
} else {
asm volatile( "frstor %0"
: : "m" (tsk->thread.i387.fsave) );
}
}
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