I feel rather dumb but can't help myself. I have a loop with calling Setexc(0x4ba, -1). For instance I want to wait four 200 Hz ticks. However sometimes (not always but definitely very often, like in 80% of cases) whole loop just locks down. So instead of having one quick call where I wait for one tick I get a zillion of trap calls until the tick counter moves to +1 (taking easily one minute!).
Since the code is trivial and debugged, the only explanation left is that traps actually enjoy higher priority than MFP interrupts (in this case Timer C) but it feels wrong -- MFP is IPL 6 (basically the same as 7, i.e. the highest possible IPL) so I find it hard to believe. But maybe I'm wrong? Timer C is rather low on MFP interrupt priority list but still, it is an IPL 6, right?