On Thu, Apr 11, 2002 at 09:42:42AM -0400, Andrew Gallatin wrote:
> 
> Denis Serenyi writes:
>  > I've been looking at adding an SSE bcopy that runs at user-level to a 
>  > program that I'm working on. I'm using FreeBSD 4.3 currently.
>  > 
>  > I wrote the routine, and when I execute it, I get an illegal instruction 
>  > exception when I try to execute the first SSE instruction (movups).
>  > 
>  > After searching the hackers archives, I'm guessing that this is because 
>  > FreeBSD 4.3 does not execute the instructions at boot time to enable SSE 
>  > instructions to be executed, and also because FreeBSD 4.3 does not save 
>  > the 128-bit SIMD registers on context switches.
>  > 
>  > Am I correct in this assessment?
>  > 
>  > It also seems like this support has been added to FreeBSD 4.5. Is this 
>  > correct?
>  > 
>  > Assuming yes, in what release was SSE support added to FreeBSD? Has 
>  > anyone done a patch that can be applied to FreeBSD 4.3, or are the 
>  > changes non-trivial?
>  > 
> 
> As David says, have a look at
> http://kobe1995.net/~kaz/FreeBSD/SSE.en.html  There is a patch there
> for 4.3.
> 
> What are the performance implications to an SSE bcopy?  How much
> faster is it than a normal bcopy?   
> 
> Would you consider releasing your code under a BSD license so that
> others could play with it, and possibly integrate it (or something
> based on it) into FreeBSD?

Also if he wants to check if OS SSE support is enabled, he can check if
the hw.instruction_sse sysctl is set to 1, then he'll know if it's safe
to use :)

-- 
Simon Dick                                      [EMAIL PROTECTED]

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