G5/Panther and Rev

[Dar Scott]

On Friday, June 27, 2003, at 06:20 AM, Ken Norris wrote:

> I don't know what SIMD is. Can you explain?

Single-Instruction -- Multiple-Data

A single machine instruction that applies to several groups of data 
items in concert.  This need not be at the same time, the processor 
might quickly iterate through these.

We have this as a high-level language feature in Transcript.  For 
example, + can work on arrays as well as numbers.  This does not mean 
that this is translated to an SIMD instruction in the engine 
implementation.  However, the feel is the same.

Maybe it would possible for the engine to keep arrays that are the 
result of arithmetic in a special form, just as it keeps the results of 
simple arithmetic in a special form.  That special form might be 
optimized for speed and maybe take advantage of SIMD instructions.  
However, I suspect only a few of us use arithmetic on arrays and then 
only a few of that group use very large arrays.

Perhaps there are image handling and a few other areas where fancy 
capability might apply.

Dar Scott