With help from Tim Litt, I think we've arrived at the right answer:
1. cpu_reset should CLEAR PS for all processors EXCEPT T11.
2. boot routines should jam PS = 340, which is what is expected today.
#1 is based on an examination of specs, manuals, and schematics for all
the PDP11 CPUs. In particular, all TTL systems wire the flops/registers
that implement PS<7:5> to clear on processor init, which is triggered by
the START switch. The LSI11, F11, J11 clear PS on microODT GO
(equivalent of hitting the front panel START switch). The T11 sets PS =
340 on init.
#2 is based on an examination of the official boot ROM listings. While
there may be paths through the boot ROMs that don't set PS = 340, the
primary path does that, and it is known to work with all the existing
boot ROMs in the simulator.
The PDP11 cpu will implement a new routine:
cpu_set_boot_pc_pw (int32 pc)
It will set saved_PC to the argument and set PS = 340. 16 boot routines
will need to be modified (gulp).
/Bob
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