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Message
From: Joachim Strömbergson<Joachim.Strombergson@I...>
Date: Tue Aug 17 09:21:15 CEST 2004
Subject: [oc] Parallel Array Processor Project
Aloha!markus@r... wrote:
> 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.
Yes I have. I would say that quite a lot (most?) DSP programming is done in C,
albeit with more or less lots of pragmas and calls to (inlined) library
functions sprinkled whithin the code. DSP codes are much more regular with the
bulk of the execution located in specific kernels. The kernels however might
be written in optimized assembler for the specific architecture.
Programming DSPs can be quite a challenge, both due to non-orthogonal
instruction sets and (for example TIs 6000 series) VLIW and multiple core
architectures.
TI, AMD, AD etc spends lots of money developing good compilers for their
architectures.
> 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.
Stack based cores for embedded multiprocessor applications are a very fine
idea. There have been some work done on this, but I have few references for
you. One thing to consider is how to implement/include the communication
semantics. You could do this by adding a communication co-processor that
extends the instruction set with port semantics. Doing this pushes/exposes the
syncronization to the user and removes lots of burden for the HW implementation.
> 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.
You mean you have a pcode generator? ;-)
> The stack-based PSM would have a very dense instruction set and it
> would be versatile with small efforts.
Yep!
--
Med vänlig hälsning, Yours
Joachim Strömbergson - Alltid i harmonisk svängning.
VP, Research & Development
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