/*
* math coprocessor error
*/
static void
matherror(Ureg *ur, void*)
{
ulong status, pc;
/*
* a write cycle to port 0xF0 clears the interrupt latch attached
* to the error# line from the 387
*/
if(!(m->cpuiddx & Fpuonchip))
outb(0xF0, 0xFF);
/*
* save floating point state to check out error
*/
fpenv(&up->fpsave); /* result ignored, but masks fp exceptions */
fpsave(&up->fpsave); /* also turns fpu off */
fpon();
mathnote();
if((ur->pc & 0xf0000000) == KZERO){
mathstate(&status, &pc, nil);
panic("fp: status %#lux fppc=%#lux pc=%#lux", status, pc, ur->pc);
}
}
static void
mathnote(void)
{
int i;
ulong status, pc;
char *msg, note[ERRMAX];
mathstate(&status, &pc, nil);
/*
* Some attention should probably be paid here to the
* exception masks and error summary.
*/
msg = "unknown exception";
for(i = 1; i <= 5; i++){
if(!((1<<i) & status))
continue;
msg = mathmsg[i];
break;
}
if(status & 0x01){
if(status & 0x40){
if(status & 0x200)
msg = "stack overflow";
else
msg = "stack underflow";
}else
msg = "invalid operation";
}
snprint(note, sizeof note, "sys: fp: %s fppc=%#lux status=%#lux",
msg, pc, status);
postnote(up, 1, note, NDebug);
}
/*
* math coprocessor error
*/
static void
matherror(Ureg *ur, void*)
{
ulong status, pc;
/*
* a write cycle to port 0xF0 clears the interrupt latch attached
* to the error# line from the 387
*/
if(!(m->cpuiddx & 0x01))
outb(0xF0, 0xFF);
fpalloc();
/*
* save floating point state to check out error
*/
fpenv(&up->fpsave);
mathnote();
if((ur->pc & 0xf0000000) == KZERO){
mathstate(&status, &pc, nil);
panic("fp: status %#lux fppc=%#lux pc=%#lux", status, pc, ur->pc);
}
}
/*
* math coprocessor emulation fault
*/
static void
mathemu(Ureg *ureg, void*)
{
ulong status, control;
if(up->fpstate & FPillegal){
/* someone did floating point in a note handler */
postnote(up, 1, "sys: floating point in note handler", NDebug);
return;
}
switch(up->fpstate){
case FPinit:
fpalloc();
fpinit();
up->fpstate = FPactive;
break;
case FPinactive:
/*
* Before restoring the state, check for any pending
* exceptions, there's no way to restore the state without
* generating an unmasked exception.
* More attention should probably be paid here to the
* exception masks and error summary.
*/
mathstate(&status, nil, &control);
if((status & ~control) & 0x07F){
mathnote();
break;
}
fprestore(&up->fpsave);
up->fpstate = FPactive;
break;
case FPactive:
panic("math emu pid %ld %s pc 0x%lux",
up->pid, up->text, ureg->pc);
break;
}
}
