[A83] Re: Special ram areas?
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[A83] Re: Special ram areas?
What does LDDR do?
----- Original Message -----
From: "Henk Poley" <HPoley@DDS.nl>
To: <assembly-83@lists.ticalc.org>
Sent: Sunday, November 11, 2001 3:02 PM
Subject: [A83] Re: Special ram areas?
>
> > Van: Joe Pemberton <dArkSk8eR@buffbody.com>
> > >
> > >>> Van: Ronald Teune <rtwolf@gmx.net>
> > >>>
> > >>>>The stack starts at FE6Fh. It is safe to use 200 bytes at least.
Even
> > >>>>then, here's still room for about 50 pushes.
> > >>>
> > >>>Is that on 83 or +?
> > >>
> > >>It's for the Ti82, Ti83, Ti83+ and Ti83+ SE... And probably even for
> the
> > >>Ti85 and Ti86...
> > >
> > >The FE6Fh too?
>
> For the Ti82/83(+) it is... (as I said, dunno about 85/86)
>
> > >And should I do "ld (FE6Fh-200)" or ld (FE6Fh+198)" ?
> >
> > The stack grows downwards, so you would want to do ld (fe6fh+199).
>
> Since you probably just want to put a 'patch' of code there I would use
> LDIR (or LDDR):
>
> ld hl,code_for_stack
> ld de,$FE6F
> ld bc,size
> ldir ; Load (HL) to (DE), BC bytes, increments
>
> That should be it...
>
> Moving the SP down (and putting your code at >$FFFF) is not a good idea,
> the TIOS sometimes resets the system (and FP) stack. Don't know how often
> this happens. Plus at return from an asm program it restored the SP (saved
> by TIOS), you could off coarse 'manualy' change that value...
>
> Henk Poley <><
>
>
>
>
>
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