[comp.sys.amiga.tech] Speed vs Multitasking

mt87692@tut.fi (Mikko Tsokkinen) (05/25/90)

In article <1623@lpami.wimsey.bc.ca> lphillips@lpami.wimsey.bc.ca (Larry Phillips) writes:

>  Has somebody checked what low 16k ($0000-$ffff) memory contains. I'm asking
                             ^^^^^^^
 Because of brain damage I wrote 16k when I ment 64k! To be more precise
first 32k and last 32k. The Idea is to use short absolute addressing which 
is actyally quite a bit faster than long!

> this because that's the fasted memory in standart 512k machine. All alloc-
> mems fail. I think I will kick the operating system out, move low 16k
> somewhere and when the program has ended move it back. Somebody said that
> it contains some track.device buffer but that doesn't matter, I'm using
> my own disk-routines anyway. Any other solutions? I need the speed for
> real time 3D landscape & object handling.

 MITT


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jesup@cbmvax.commodore.com (Randell Jesup) (05/26/90)

In article <MT87692.90May25115813@uikku.tut.fi> mt87692@tut.fi (Mikko Tsokkinen) writes:
>In article <1623@lpami.wimsey.bc.ca> lphillips@lpami.wimsey.bc.ca (Larry Phillips) writes:
>
>>  Has somebody checked what low 16k ($0000-$ffff) memory contains. I'm asking
>                             ^^^^^^^
> Because of brain damage I wrote 16k when I ment 64k! To be more precise
>first 32k and last 32k. The Idea is to use short absolute addressing which 
>is actyally quite a bit faster than long!

	Yes, it's somewhat faster, but on a 68000, d16(An) is just as fast
and small as Abs.W addressing.  Just set up a base register, and you can make
ANY 64K you want "fast".  And this way, you can cooperate with the OS, instead
of being nasty to other programs and users (and perhaps breaking in unexpected
configurations).

-- 
Randell Jesup, Keeper of AmigaDos, Commodore Engineering.
{uunet|rutgers}!cbmvax!jesup, jesup@cbmvax.cbm.commodore.com  BIX: rjesup  
Common phrase heard at Amiga Devcon '89: "It's in there!"