[A83] Re: Special ram areas?
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[A83] Re: Special ram areas?
same as ldir, but it decrements instead if increment,
so it copies BC bytes from HL to DE, but you specify the ending points instead of the starting points...
>
> 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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