Re: A86: Memory Expander
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Re: A86: Memory Expander
The method of keeping the stacks on page 1 does have one advantage... if a
program was written that actually checked the values of _OPS and _FPS before
blindly overwriting that page, it could return with an error if there was
not enough space.
/Most/ of the usage of RAM page 1 is a result of sloppy programming =P (I am
also a culprit with sc2k)
----- Original Message -----
From: <rabidcow@juno.com>
To: <assembly-86@lists.ticalc.org>
Sent: Friday, March 10, 2000 11:08 AM
Subject: Re: A86: Memory Expander
>
> the size of the stacks has nothing to do with asm. these are used for
> basic return addresses (and asm if you call an external program) and fp
> number storage during large calculations. the problem with asm programs
> is that many of them will use page 1 as scratch space and blindly write
> over the variable data. (ashell does not do this...)
>
> you can move _FPS and _FPBASE to _alt_int_chksum, _OPS and _OPBASE to
> _altram_end-1, and set SIZE to 0.
> that gives you 804 bytes for the stacks and 112k for variables (shows up
> as 14688 on MEM:RAM screen :)
> this will also get you in trouble if you have any _alt_... programs
> installed, or if by some freak chance the data on the stack sets one of
> the checksums right :)
>
> -josh
>
> On Fri, 10 Mar 2000 11:26:24 EST RoniBarrett@aol.com writes:
> >
> > In a message dated Fri, 10 Mar 2000 7:13:50 AM Eastern Standard
> > Time, "Andreas Finne" <a_finne@hotmail.com> writes:
> >
> > >
> > > How large does the memory space have to be for the stacks?
> >
> > The expander program leaves 1024 bytes. This should work for most
> > use. If you dont have any asm programs on the calc, and only use it
> > for math, you can probably set it somewhat lower. There was a
> > reference in the comments of the program to 256, wasnt there? Is
> > that for "normal" (i.e. no asm programs) useage?
> >
> >
> > Jeff Barrett
> >
>
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