Vectorizing motion 8

["Nate Hayes" <nh@xxxxxxxxxxxxxxxxx>]

Sylvain Pion wrote:
> My goal here is to make it *easy* for hardware vendors
> to support the critical interval operations.  That is,
> it should be a relative no-brainer to extend an existing
> SIMD unit to support the interval functions of this standard.
>
> Concretely, what I would propose instead would be to have
> functions like sqrt(x) which return an interval y, together
> with the "exceptional" information in a separate (integer) register i.
> This should vectorize without problem, with an accompanying
> integer vector-register.
> Then if you need to propagate or combine the information
> one way or another, you do it by considering the information
> registers.

I also agree with all of this, although IMHO what you describe is a concrete 
implementation of a decorated interval. So it is an example of a (would-be) 
conforming implementation.

For example, if the values in the integer registers are not propogated, then 
this can be viewed as a "forgetful" operation.


> Of course, at the programming language level, one can
> encapsulate all the propagation rules the way the motion says
> (or rather, says a later motion would specify).
> But I think that this part should not be specified in this standard.


I agree.
This was by design.

Sincerely,

Nate