Re: IIGS memory error

[dempson@actrix.gen.nz (David Empson)]

David Empson <dempson@actrix.gen.nz> wrote:

> ground.ecn AppleII Librarian <apple2pd@garp3.icaen.uiowa.edu> wrote:
> 
> > I haven't determined memory mapping for the 1Mb Apple expansion card
> > yet. Board with 256K shows memory to $12000 ???, with 512K memory goes
> > to $16000 ???.  So I think MB = $80000, plus $40000 per 256K.  (I am
> > trusting my memory here so I may be wrong. In fact, this can't be
> > right).
> 
> $10000 is 64K, so 256K is $40000 (4 times 64K) and 1 MB is $100000 (16
> times 64K).
> 
> You didn't do your hex arithmetic right.  Assuming the numbers you saw
> were actually $120000 and $140000 (one more zero in each case),

Sorry - typo there - I meant $120000 and $160000.

> then $120000 - $40000 = $E0000 (not $80000).

-- 
David Empson
dempson@actrix.gen.nz