6 Feb
2003
6 Feb
'03
11:53 a.m.
On Thu, 6 Feb 2003 15:28:00 +0000, Steve Harris wrote
On Thu, Feb 06, 2003 at 03:59:31 +0100, Dave Griffiths
wrote:
Is this processor specific? I used to get it loads on my PII desktop, but I
haven't noticed it as much my PIII machine (might just be because it's twice
the speed).
Cheers for the info guys, I haven't come across this before (day job=games
programming)
dave
On Thu, 6 Feb 2003 14:07:06 +0000, Steve Harris
wrote
I use:
#define FLUSH_TO_ZERO(fv) (((*(unsigned int*)&(fv))&0x7f800000)==0)?0.0f:(fv)
I think it came from the music-dsp list.
Its uses pointer casting, which is mildly evil, but C doesn't have a
non-interprting cast like C++ has, I cant remeber the C++ syntax,
but it should be easy to convert.
It looks for the denormal pattern in the IEEE bitpattern and zeros
the float if its there IIRC. You probably can't do the comparison
with < as that would cause the denormal to be evaluated. On Thu, Feb 06, 2003 at 12:18:47 +0100, Dave
Griffiths wrote:
ahah, I was hoping for an explanation :) any ideas on how to combat this, what
the squashing threshold should be? I had a vague attempt at doing something like
this (after noticing that
filters filtering silence uses up a lot of cpu). Each sample buffer object
OT: Thats probably because the zeros weren't 0.0, they were probably
denormal numbers. If you squash them the filter will run at the same
cost as when its processing any other data.