> Intel uses 80 bits float in internals, but load/store uses 64 bits 
> float. Load/store looses least significant bits.

Exactly.  If your Intel machine is Pentium 4 or newer, you can get
around this by using the SSE2 extensions, which work with 64-bit doubles
throughout.  I don't remember offhand precisely which gcc flags you need
for this.

> Hey, floating point numbers are funny :-)

Yup.