Preventing gcc from aligning stack???

[Horst von Brand]

"H. Peter Anvin" <hpa en transmeta.com> said:
> Tuukka Toivonen wrote:
> > On 25 Jan 2000, H. Peter Anvin wrote:
> > > The native fp format on IA32 is "long double" -- 80 bits (10 bytes).

> > Yes, but this is not relevant here. The 10byte floating point is used in
> > practice only internally to the FPU. Yes, you can read and store it but
> > nobody does that, since it's so much slower than a normal float or double
> > (on Pentium, atleast).

> You have to if you're going to spill a register.

gcc doesn't do that, it stores FP as doubles (8 bytes) always. This can
give different results according to the way the computations are done
(different roundings when storing different intermediates), so they provide
the -ffloat-store option, which stores all intermediates to memory (rounds
them to 8 bytes).

This is from egcs-1.1.2, but this hasn't changed in quite some time AFAIK.
-- 
Horst von Brand                             vonbrand en sleipnir.valparaiso.cl
Casilla 9G, Viña del Mar, Chile                               +56 32 672616

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