More PDP-11 problems

[Patrick Finnegan]

Charles declared on Saturday 31 December 2005 20:32:
> When I examine memory at 173000 it's all 1's (177777) but I can
> deposit and read data correctly into locations there. Shouldn't
> the bootstrap program be copying its code there? 

No.  Because of 16-bit addressing vs 18-bit addressing, what the ODT 
shows at 173000 is really "memory"/IO address 773000.

> Again, if the 
> HALT line is being set for some reason, then the copy operation
> can't take place... is that where I should be looking or am I
> following a false trail?

There's no copy, reading from address 173000 gets translated by the MMU 
to 773000 automagically.

Pat
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