Path: chuka.playstation.co.uk!scea!peter_alau@playstation.sony.com
From: Gerrit Goossen <gerrit@funnytown.com>
Newsgroups: scee.yaroze.programming.3d_graphics
Subject: Re: GsLinkObject4 Confusion - On to GsSortObject4 - And Now CW Asm
Date: Mon, 31 Aug 1998 09:48:30 -0400
Organization: SCEA News Server
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>Gerrit Goossen wrote:
>
>> >Ho hum...  I need direct GTE access and the ability to sort 2D primitives, and I
>> >need it NOW!
>>
>> I actually spent quite a bit of time trying to access the GTE with
>> inline ASM in CW, but for some reason CW doesn't want to let me do it! I
>> wonder if this is also a problem with GCC, although it doesn't really
>> matter since I'm on a Mac anyway...
>
>You cann't use GTE inline from the Yaroze version of CW. Or the
>Yaroze GNU either.

I love it when I do stuff that people tell me isn't possible!

As it turned out, the only reason my code was crashing was because I
wasn't putting a final nop after ja'ing. *None* of the examples in the
CW manuals do this (and so they won't work as they appear in the
manual!) and if I had been using GCC I believe it would have added this
for me (?), but I finally I noticed that Metrowerks used an extra nop in
_psstart.c and decided to give it a try... (So I'm relatively new to asm
:^)

Anyway, for any other members interested in R3000 ASM or using the GTE
directly, here are a few places you might want to check out:

<http://www.idt.com/products/risc/32bit.html> - Check out the RC3041
manual for plenty of info that's "mostly" compatible with the R3000.
(Anyone know where to find the R3000 manual?)
<Page 13 of Your User Guide> - Page 13 explains register assigments
which are of course extremely useful even though CW doesn't always
appear to follow them (!?)
<http://www.in-brb.de/~creature/codehack.htm> - A "sketchy" site with
valuable info on how to access GTE functions. (From my understanding of
our Yaroze license, we are free to get info from sites like these we
just can't contribute to them. Sounds fair to me!)

FWIW, I've been able to speed up my gouraud fogging from over 400 hsyncs
for 500 primitives to under 250 hsyncs. It's still too slow, but I'm
making progress. If anyone's interested in the code that does this, say
the word and I'll be happy to post it here. (*Especially* if you think
you might be able to help me speed it up. There's *plenty* of room for
optimization. ;)

- Gerrit