[A83] Re: Special ram areas?

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[A83] Re: Special ram areas?


true... but a font set wont be small and that would slow down any text
display routines significantly since it would need to be run every time the
tios displayed a character.  Olle's idea of archiving external fonts then
using rom paging to read them sounds like a better idea.

----- Original Message -----
From: Joe Pemberton <dArkSk8eR@buffbody.com>
To: <assembly-83@lists.ticalc.org>
Sent: Thursday, November 01, 2001 10:01 PM
Subject: [A83] Re: Special ram areas?


>
>
> >
> >How do you intend to check if the file is still in the same location it
> used
> >to be in?  When a program moves, sometimes the data in the old location
> gets
> >overwritten.  Sometimes it doesn't.  Just like a quick format doesn't
> really
> >erase the data on your disk, only the vat changes.  So whats the problem
> >with that?  Nothng if the entire data is completely unwritten but more
> >likely the data will be half there, half not.  So you would need to check
> if
> >the vat entry's pointer remained the same... but the vat entry could also
> >move w/o the file actually moving... So the only 100% bug free way to do
> >this is to use vat romcalls to search for it.  Of course this problem I
> >outlined would be rare and might slip through beta testing.
> >Brandon Sterner
>
> There is an easy way to make 99.99% sure the contents of the program is
> intact and still in the same memory location - do a Cyclic Redundancy
> Check.  Add up every single byte in the compiled routine (the actuall
> binary values for the opcodes).  Then put a checksum at the end of the
> routine that already has the correct sum.  If the added up value equals
the
> checksum, then you can call the routine.  Else, the routine has been
> written over.
>
> Okay, maybe its not as easy as i said it was =) But its what the internet
> uses for packet checking, so it can't be that bad =p
> - - Joe
>
> >
> >----- Original Message -----
> >From: Henk Poley <HPoley@DDS.nl>
> >To: <assembly-83@lists.ticalc.org>
> >Sent: Wednesday, October 31, 2001 2:18 PM
> >Subject: [A83] Re: Special ram areas?
> >
> >
> >>
> >> > Van: BRANDON STERNER <bms9019@osfmail.isc.rit.edu>
> >>
> >> It might be a good idea to create a new program and copy your fonthook
> >into
> >> it (or just make one yourself with TASM and bin2var). Give that
> >> 'fonthook'-program some distinguishable header. Then make a routine
that
> >> knows the last correct adress of the file, checks if it's still there
> >> (fast), looks it up if not (slow), and jumps to it. Such code would be
> >> small, and could fit into the stack area. This way you are compatible
> with
> >> almost all programs that exist for the Ti83+ I guess.
> >>
> >> The header and the name of the program could be the same (to safe
space).
> >> Since the lookup routine has stored where your font-hook is, you can
use
> >> that info to calculate adresses inside the program (old Ti85 style).
> >>
> >> Good luck!
> >>
> >> Henk Poley <><
> >>
> >> > You really cant guarantee that that location will not be over written
> by
> >> > another asm program/application.  In fact there really isn't anywhere
> in
> >> > ram that you can feel safe there won't be shifting or overwriting
> unless
> >> > your program is in complete control but the idea of hooks is that
they
> >> are
> >> > used while your program is not running.  You could always look up the
> >> > program in the vat but that would be insanely inefficient.
> >> >
> >> > On Wed, 31 Oct 2001, Ronald Teune wrote:
> >> >
> >> > >
> >> > > Hi,
> >> > >
> >> > > Dunno if I told it, but I'm planning to make a font app, with
> external
> >> font
> >> > > support, if possible. If I have external fonts, I need to transfer
> >them
> >> to a
> >> > > static location in ram, like ion's 9F60 or so. Is there another
such
> >> > > location that won't shift through memory? How does ion do it?
> >> > > Another one: The ti-font is 5 pixels wide, but bytes are 8 bytes.
Do
> I
> >> have
> >> > > to fill the rest with zeroes? Can anyone (Andy Hochhaus?) tell me
> what
> >> to
> >> > > change if I want to make a big font? And can anyone tell the use of
> >> eea? I
> >> > > don't see it. Maybe if I downloaded it, this will change.
> >>
> >>
> >>
> >>
> >
> >
> >
> >
>
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