On 01/07/11 16:54, Paolo Bonzini wrote: > On 07/01/2011 04:55 PM, Stubbs, Andrew wrote: >>> > >>> > What about (u128)c + (u64)((s8)a * (s8)b)? You cannot convert this to >>> > (u128)c + (u128)((s8)a * (s8)b). >> Oh I see, sorry. Yes, that's exactly what I'm trying to do here. >> >> No, wait, I don't see. Where are these multiple widening multiplies >> you're talking about? I only see one multiply? > > I meant one multiplication with multiple widening steps. Not clear at > all, sorry.
Yes, I see now, the whole purpose of my patch set is widening by more than one mode. The case of the multiply-and-accumulate is the only way there can be more than one step though. Widening multiplies themselves are always handled as one unit. Andrew
