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Message
From: markus at reaaliaika.net<markus@r...>
Date: Tue Aug 17 08:47:16 CEST 2004
Subject: [oc] Parallel Array Processor Project
Joachim:
> (Going extremely off charter for the list here... ;-)
Well, it's just fun sometimes ;-) But I have not any additions to
the "Matrioshka Brains" - it's simply the computer I would like to have at
my desk.
---
Me: "But a simple processor core should be able to be clocked with
higher frequency than a 40-stage pipelined P4. And, if the cell data
width is kept in 8-bits, it should be faster than it's 32/64-bit cousins."
I of course meant, that the clock frequency of 8-bit processor should be
higher than it's 32/64-bit counterparts (because of shorter propagation
paths inside the processor). With the same frequency, wider processors
are usually faster.
---
<somewhat offtopic>
Nico: "I have heard about C + extention to use the paradigm of uniform
memory adressing."
Have anyone programmed DSPs with C (or other higher level language)?
In my other project, a DSP-based guitar effect box, I'm programming
Motorola DSP56303. It's very hard to try to express variable allocation
from different kinds of memories (internal/external, X/Y/P/L) and it's very
hard to write a good C compiler for these. And trying to write an OS:
very unpleasant job, indeed.
That's why I changed back to the assembler in that project... :-)
---
PicoBlaze/KCPSM: I've read the article sent by Joachim. Yes, I've
thinking of constructing the array from the processors something like
these.
There were one idea I haven't even think about - constructing a stack-
based PSM. The author has rejected this because it's not very
straightforward to program, but that doesn't matter in this project.
The compiler could be easily modified to output reverse polish program
for the cell. In fact, it's easier to do this than make the compiler to
output programs for register-based PSMs.
I have tried to say in my web pages, that the compiler can be
programmed to output almost any kind of code for cells - the cell can
have a fixed instruction set or it can be microprogrammamble (i.e.
compiler outputs code to directly access the internal muxes). Not all
instructions need to be hard-coded for the cell; microprogrammable cell
can be programmed to perform more complex operations, like
multiplication.
The compiler can utilize the cells even more - it can collect parts of the
software (for example, short equations, iterative loops) and convert
those to be executed in one cell.
The stack-based PSM would have a very dense instruction set and it
would be versatile with small efforts. Certainly I have think about this
more closely.
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