Question about CPU support and applications

[Dave Beauvais]

I've noticed a trend among developers to target their applications to two CPU types: ARM and MIPS. Why do so many developers omit the SH3 CPU? I have a friend with an old HP Jornada Pocket PC 2000 with an SH3 CPU who can't run many newer games that other PPC 2000 devices can. I guess I assumed it was just a relatively simple task to compile the app for the various CPU types. For example, he's a pretty big RTS fan, but the new Warfare Incorporated won't run on his Pocket PC since there's no SH3 version of the game.

I'm more curious than anything. I'm guessing it's somewhat more complicated than just defining the SH3 as the target CPU or more apps would run on them today. Any developers want to shed some light on this for me?

Thanks!

--Dave

[Peter Foot]

For simple applications it might be as straight forward as recompiling for SH3 (followed by full testing on an SH3 device to ensure there are no quirks between the versions). However in the case of games, especially those pusing the boundaries they may be introducing processor specific code to squeeze the maximum performance - they may have therefore decided it is not worth their time to invest in additional coding specifically for the SH3 architecture, or they may have decided it is just not up to the job performance-wise.
I can only expect this trend to continue such that ARM may be the only supported variant for Pocket PC software since Pocket PC went ARM-only from 2002 onwards, the fact is that catering for the different architectures dramatically increases the testing and support effort required.

Peter

[Dave Beauvais]

I hadn't thought about developers using CPU-specific instructions or routines. That makes a lot of sense now that you mention it. Thanks for that summary!

--Dave