19 Jun
2013
19 Jun
'13
4:58 p.m.
On 2013-Jun-19 10:44 , Bob Breuer wrote: [...]
So I fired up my SS-20 and did a little poking around to see how the SuperSparc-II behaves here.
- page not mapped: read/write = Data Access Exception
- sbus timeout: read = Data Access Exception, write = Level 15 int
- afterwards, SFSR will always be cleared to 0
For cpeek/cpoke, OBP will catch the Access Exception and Access Error, but it won't catch the Unaligned Access or Level 15 int.
Yeah - on current generation sparcs, I/O write failures aren't notified until long after the instruction has gone past. That generally means that PIO write failures generally don't get reported at the OK prompt - they just get dropped invisibly.