Tony Lawrence 100f351575 PDP11: RP11: Interrupt on IE+RESET+GO ...

Recent analysis of the 2.9BSD kernel revealed that RP11 was
expected to interrupt on control RESET function if IE bit was
also set.  Documentation was not very clear of the fact, saying
in one place that RESET+GO does not interrupt (which is not
contradictory with the above because it does not mention IE).

In other place, however, it says that IE always causes interrupt
when DONE is asserted.  Thus, since RESET does assert DONE, an
interrupt should be posted if IE is set.  The autoconfig binary
from 2.9BSD uses this feature of RP11 to check the presence
of the controller.

Formerly RESET was always clearing RPCS with DONE unconditionally,
and that reset IE as well.  This patch makes sure that the IE bit
is preserved, and if set, it posts an interrupt when RESET asserts
DONE.

2024-06-13 21:42:44 -04:00

63 KiB

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