[A86] Re: assembly, programing and games

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[A86] Re: assembly, programing and games


afaik, the "filesystem" is basically the same, except all pointers are 3
bytes.
I believe ti actually has some useful info on this, otherwise try link
protocol descriptions & the standard include files.


paging is pretty simple once you get used to it.  translate the three
byte address like this:
   ; address is in ahl
   call _conv_ahl ; should = $4633
   ; now a=hardware page, hl="paged-in" addr
   out ($04),a    ; $4000-$7fff
   inc a
   out ($05),a    ; $8000-$bfff
   ld a,$c0       ; flip bits because we
   xor h          ; moved $8000 to $4000
   ld h,a
now hl->happy data, just like other calcs, except after you process 16k
past that point you have to swap pages:
   ; hl = hl from above + 16k
   in a,($05)
   out ($04),a
   inc a
   out ($05),a
   ld a,$c0
   xor h
   ld h,a
of course, you can't do that if you want to use rom calls in the middle
of that, and you have to remember to do a
   ld a,$0d
   out ($04),a
before use any rom calls after that.  (unless you get the page 0
address...)

ok, maybe it doesn't look so simple :)
look at the include files.  there's rom calls for this stuff too, they're
just slower.  With the rom calls you can work directly with the 24 bit
pointers, but it has to check after every byte instead of every 16k
because it only loads one bank.  (probly more useful for
one-byte-at-a-time transfers)

-josh



On Sat, 10 Mar 2001 11:09:34 +0100 "Henk Poley" <HPoley@DDS.nl> writes:
> 
> Where can I find info about the filesystem of the Ti-86?
> 
> I'm almost finnished with the fopen(), etc. routines for a C 
> compiler, but
> I've only made them for the Ti-83. As far as I know, the 
> filehandling on
> the Ti-85/86 will be more difficult, because of the RAM-paging etc.
> (porting to the Ti-82 -off coarse- will be much easier)
> 
> So I'll need some help.
> 
> Don't say "we don't need a C compiler". I know you don't want to 
> have one,
> but it's just one if my *little* projects. Always nice to have 
> something to
> do ;)
> 
>         Henk Poley
> 
> 
> 
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