Path: chuka.playstation.co.uk!news
From: "John Blackburne" <johnb@hk.super.net>
Newsgroups: scee.yaroze.programming.codewarrior,scea.yaroze.programming.codewarrior
Subject: Re: GTE asm with CodeWarrior
Date: Tue, 26 Jan 1999 22:04:10 +0000
Organization: PlayStation Net Yaroze (SCEE)
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 (Sean Kennedy) wrote:
> That does not mean that the Yaroze system can be used for Assembler
programming.

It can. Details follow.

> Hah, nothing in the "documentation" says anything

See pages 81 - 87 of the PDF file "C Compiler Reference MIPS", from the
CodeWarrior CD.

> but I noticed a
> few Metrowerks examples and .h files that contained defintions that
> allowed GTE / GPU optimizations in assembler.

There's that too: ASM.H is the interesting one as it lets you refer to R3000
registers by standard names.

> Wait a minute here. The assembler will ony make sense to those that know
> what its true register designation defintions do and are documented.

MIPS assembly, including register and calling conventions, e.g. which
registers variables are passed in, is fully & publicly documented. You can
find the info online and in bookstores. The CodeWarrior Docs give some
references. The CodeWarrior docs do not include this info, rather they
describe MetroWerks implimentation of MIPS assembly. Together with the
public docs it tells you everything you need to know to be able to program
in assembler on Yaroze.

> Nice motives, just stick to what you know you can do with supporting
> documentation.

I plan to.

> Assembler is a very powerful developer tool if you know EXACTLY what you
> are doing at ALL Times.

I do (mostly).

> This example is a clear case of someone who got a
> code snippet, and tried using it without proper file/library support in
> the compiler.
> However, if Sony had released an assembler fragment to allow "lets say"
> Force feedback control as part of the GetPadBuf() routine, to allow an
> output. Called PutPadBuf( *padFF_Info ) and there was good documentation
> support. Then Yes Metrowerks CW for Net Yaroze can compile the assembler
> source, and it would work. But it is easier to maintain these hooks in
> Library Upkeep in the file: LIBPS.A
>
> Assembler is like digging a post hole with a teaspoon.
> Keep in mind, you have control over EVERY Little Piece of Dirt.

For most coding it's better to work in a high level language such as C:
going to assembler provides little benefit if most of the work is done by
libraries, or if the code is non-critical. But there are many occasions
where you will see significant gains after re-coding in assembler. And even
if you always code in C a good understanding of the processor and its
assembly language can help you write much better code, on the Yaroze as much
as any other processor.

John