Goose (goose@goaway.com) on 6/21/08 wrote:
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>@DK I think 3DNow is what you were after.

Yes 3DNow!?!?!?! was exactly what I was thinking of. Thanks for remembering.

>I was actually disapointed that we only got 8 extra register >with AMD64. 32 in
>total would have been nice, afterall they were sort of >starting fresh.

Most of AMD's studies showed that 32 didn't have a tremendous net performance gain. I also don't know how much it would have cost in terms of instruction encoding.

>That being said I suppose it was risky to invest too much >die space on something that may well have not taken off.

Yes, that's certainly another issue. Also, there is an additional cost to having more registers - you have to replicate all of that state for multithreading. x86 is vastly easier to multithread than IPF or RISCs in general.

I think GPUs are also beginning to show that light weight threads are the way to go.

DK