about the sse comment
gcc3.2 (and 3.1) work with sse/sse2, but there are still a ton of x87 calls
based on the way the code is laid out.
unfortunately based on my testing the windows binary is still at least 10%
faster than the best binary I was able to make with gcc 3.2.
I think the code needs to be restructured to get a big speed boost.


"Micha Riser" <mri### [at] gmxnet> wrote in message
news:3dc0ffc1@news.povray.org...
Thorsten Froehlich wrote:

> In article <chr### [at] netplexaussieorg> ,
> Christopher James Huff <chr### [at] maccom>  wrote:
>
>>> You are running a compile for PIII on a PII? Why are you surprised that
>>> it doesn't work?
>>
>> Read it again...the PIII optimized compile is the faster one on his
>> machine.
>
> Yes, but as the Pentium II does not support the SSE instructions it is
> surprising that it works at all!  Apparently the compiler used doesn't add
> a lot of SSE instructions...

gcc 3.1 does not use the SSE instruction by itself, you would have to use
inline assembler to make it use them. So there is porbably only a few
PIII-specific instructions left that it uses at all. This explains why it
sometimes works on a PII as well. I had even turned off the SSE
optimization when I compiled with the Intel compiler (only some of the
5-components colour calculations could have been vectorized anyways)
because it did not result in a speed-up, but rather a slow-down.

- Micha

--
objects.povworld.org - The POV-Ray Objects Collection
book.povworld.org    - The POV-Ray Book Project

Post a reply to this message