Flushing denormals to zero

Mantis mail.mantis.88 at gmail.com
Fri Feb 17 00:09:40 PST 2012


17.02.2012 4:30, bearophile пишет:
> After seeing this interesting thread:
> http://stackoverflow.com/questions/9314534/why-does-changing-0-1f-to-0-slow-down-performance-by-10x
>
> Do you know if there's a simple way to perform _MM_SET_FLUSH_ZERO_MODE in D?
>
> According to Agner that operation is not needed on Sandy Bridge processors, but most CPUs around are not that good:
> http://www.agner.org/optimize/blog/read.php?i=142
>
> Bye,
> bearophile
>
I could expect this to be adjustable in std.math.FloatingPointControl, 
but it isn't. Anyway, the assembly code to change FPU control word is 
pretty tiny:
http://software.intel.com/en-us/articles/x87-and-sse-floating-point-assists-in-ia-32-flush-to-zero-ftz-and-denormals-are-zero-daz/


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