Re: [hatari-devel] FPU update

[Douglas Little <doug694@xxxxxxxxxxxxxx>]

Hi,

A question has raised while checking if all unnormals are caught before used for calculation:
Theoretically it is possible to write an unnormal number to an FP register using FMOVEM. Then using that register as source (or destination for dyadic operations) will input an unnormal value to the arithmetic operation. At least that currently happens in emulation. I wonder how this is handled by real hardware. Does anybody know?

I don't know for sure, but suspect that MOVEM does not attempt to catch such things, as it works on a set of values not a single value - and the result would be ambiguous if it attempted to do so. 

Throwing an exception in the middle of a MOVEM also seems unlikely - but who knows :)

EDIT - just saw the other response!

 

D