[linux-audio-dev] Traps in floating point code

Steve Harris S.W.Harris at ecs.soton.ac.uk
Thu Jul 1 05:04:23 EDT 2004


On Thu, Jul 01, 2004 at 10:25:51AM +0200, Ruben van Royen wrote:
> Hi all, 
> 
> please note that SSE2 has support for 64bit floats (doubles) and contains an 
> instruction that truncates to int, irregardless of controlwords. A new enough 
> gcc with (-march=pentium4 or -msse2) and -mfpmath=sse will use sse instead of 
> the old fp unit. This has more advantages, since sse math uses normal 
> registers instead of the stack in the old fp unit.
> 
> The disadvantage is of course that it does not run on older processors. I'm 
> also not sure what level of sse athlon currently supports. The last time I 
> looked, it only supported sse. This is also good, but it lacks support for 
> double precision floatingpoint.

Also early gcc3's will often produce code that will give bus errors, or
illigal instructions (I forget which) if you try to execute it.

- Steve


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