On Thu, Feb 06, 2003 at 11:13:45 +0100, David Olofson
wrote:
On Thursday 06 February 2003 16.28, Steve Harris
wrote:
[...]
#define FLUSH_TO_ZERO(fv) (((*(unsigned
int*)&(fv))&0x7f800000)==0)?0.0f:(fv) I think it came from the
music-dsp list.
There's a conditional in there, though.
Yes, but its not in a float context so it wont get
denormallised(?).
Well, casting to int avoids getting the denormal into the FPU. This is
probably the only safe way to deal with a denormal without forcing
the FPU to burn cycles evaluating it. I don't see how this has
anything to do with the conditional, though. It's a potential
misprediction + pipeline flush regardless of whether the controlling
input comes from the FPU or the ALU.
//David Olofson - Programmer, Composer, Open Source Advocate
.- The Return of Audiality! --------------------------------.
| Free/Open Source Audio Engine for use in Games or Studio. |
| RT and off-line synth. Scripting. Sample accurate timing. |
`--------------------------->