[hatari-devel] Latest Hatari HG version gets stuck sometimes

[Thomas Huth]

On Wed, 8 Jul 2009 23:32:19 +0200
Thomas Huth <huth at users.berlios.de> wrote:

> On Wed, 8 Jul 2009 21:06:15 +0300
> Eero Tamminen <eerot at users.berlios.de> wrote:
> 
> > Saving memory state from a freshly booted & idle GEM and then
> > restoring it with the --memstate option is 100% sure way to trigger
> > the issue for me.
> 
> OK, I can reproduce the problem this way. However, I currently don't
> have a clue how to fix it...

Phew, just found and fixed this bug. The problem was introduced with
changeset f3051bd6f969 where the place of the call to
Video_StartInterrupts() was changed in the VBL function.
After the change, the VBL function basically looked like this:

void Video_InterruptHandler_VBL ( void )
{
	Int_AcknowledgeInterrupt();
	...
	ShortCut_ActKey();
	...
	Video_StartInterrupts(PendingCyclesOver);
}

AcknowledgeInterrupt() disabled the VBL Int in int.c.
ShortCut_ActKey() is where we load & save memory snapshots.
Video_StartInterrupts() enables the VBL Int in int.c again.

So with that order the VBL Int was disabled in the memory snapshots.
As long as you used F12 or AltGr+l for loading memory snapshots,
this did not matter since StartInterrupts() re-launched the VBL.
But as soon as you used the --memstate option, the VBL was never
started again.

I've fixed the problem now by moving ShortCut_ActKey down, after the
Video_StartInterrupts() function call (like it was before the change).

Note that this fix only works for new memory snapshots, since the
disabled VBL is stored in the file of faulty snapshots.

 Thomas