[OpenBIOS] sparc32 trap recovery

Tarl Neustaedter tarl-b2 at tarl.net
Wed Jun 19 18:58:59 CEST 2013

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.

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