[A86] Re: ROM / RAM equates database

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[A86] Re: ROM / RAM equates database



On Tue, 25 Sep 2001 08:36:21 +0200 "Henk Poley" <HPoley@DDS.nl> writes:
> > Van: rabidcow@juno.com
> > On Mon, 24 Sep 2001 08:51:39 +0200 "Henk Poley" <HPoley@DDS.nl> 
> writes:
> > > 
> > > Ti86 points to. For a very basic example, $4000 (_ldhlind / 
> > > LD_HL_MHL) on the Ti83 always points $0033. 
> > > There might be more... 
> > 
> > That particular routine is at $0033 on *all* calcs, from the 82 to 
> the
> > 73. I wouldn't be surprised if most of the rst's were the same, 
> too.
> 
> Okay, I know, but the problem is I didn't know the entrypoint(s) of 
> the other calcs...

I know this is just an example, but for that one you can just use $0033
as the entrypoint.
Ah, never mind me...
 
> > > Plus the possibility to speed up programs per different ROM. I 
> know 
> > > that everybody I tell this kind of stuff says "when you use ROM
> > > routines, you know they are slow, so it is better to implement 
> the
> > > routines yourselves if you want speed.", <sigh>.
> > 
> > It would be amusing if someone were to rewrite the rom for speed 
> (test it
> > with vti) and send a copy to ti.
> 
> That would take you years to unroll all these stupid loops and 
> jumps..
> 
> Code below is an example of programflow you find quite often in the 
> Ti ROMs...
> 
> Label1:
>         ld        a,(de)
>         ld        (hl),a
>         inc        de
>         inc        hl
> Label2:
>         ld        a,(de)
>         ld        (hl),a
>         inc        de
>         inc        hl
...
> Optimizing with LDIR would be an option I think...

I think that would be the least of your worries.  Most places that do
that sort of thing also add, subtract, or something all the way through. 
I suppose you could still roll it back up into a loop, but that would
make it slower rather than faster.  Although you would be able to fit
more on page 0 then which, I think, is one key way to speed things up.

Another thing is that the rom always loads rom to the first bank, ram to
the second.  There's a lot of things you could do faster if you load
rom/ram to both banks.

-josh
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