Subject: Re: [linux-audio-dev] swh plugins and fixing undenormalize
From: Steve Harris (S.W.Harris_AT_ecs.soton.ac.uk)
Date: Thu Jun 24 2004 - 15:58:48 EEST
On Thu, Jun 24, 2004 at 01:20:34 +0200, Clemens Ladisch wrote:
> The IEEE standard specifies exactly what happens with denormals, so,
> in theory, the compiler must not optimize this away. However,
> optimization options for speed often disable strict IEEE
> compatibility. (I don't know how gcc's options behave.)
If you use -ffast-math then it note reuiqred to maintin strict IEEE
semantics. Its a lot faster for some operations if you do.
> > typedef union {
> > float f;
> > int32_t i;
> > } ls_pcast32;
>
> AFAIK this isn't safe either because the same type aliasing rules
> apply to unions, too. The only safe way is to go through char
> pointers.
OK, thats interesting. I though it was OK, in that compiler is required to
make &v.f == &v.i, where sizeof(v.f) == sizeof(v.i)? Maybe I misunderstood.
In any case my code is full of gcc-isms, I doubt it would build on any
signifiantly different compiler.
- Steve
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