Re: VFRECIP/VFRSQRT instructions
I'm looking at the cases where the reciprocal is near the boundary between finite and infinite or between normal and denormal. Are you trying to get the boundaries approximately right? Or exactly? For example, the point at which the reciprocal of a large positive denorm falls over the boundary between MAXPOS and +Inf is different for RUP and RNE. The setting of OF changes at the same point. There's yet another point at which OF changes for RDN even though the answer doesn't change. You don't show UF set anywhere.
So, I'm wondering what your paradigm is for the edge cases. I can see it might not be worth being too complicated since the answer isn't very exact. The paradigm is further complicated by the idea that the answer may be refined
by further steps. :-)
On 8/10/20 8:54 PM, Andrew Waterman wrote: