🚀 go-pugleaf

In <1992Aug26.134637.5838@leland.Stanford.EDU> bil@cmn16.Stanford.EDU (Bill Schottstaedt) writes:
>I believe the program does not fail because the out-of-range NeXT DSP
>external memory addresses are mapped back onto lower addresses.
>For example, on an 8K dsp, an address like X:$B001 actually
>writes to X:1 (external, of course = $A001).  This makes it
>harder to figure out how much memory is actually out there.

Yep, this is hard to find. If however you know what can be at the
different addresses you can test for these shadowed RAM areas.

My favourite RAM address checker fills the memory with a series of
pseudo-random numbers and checks then against the same series. Any
addressing fault or shadowing (happens when address lines are shorted as
well) will most probably be detected. Of course you need a random
number generator with a period larger than your memory :-)

Regards,
-- 
Michael van Elst
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