[Libre-soc-dev] [RFC] SVP64 on branch instructions

Luke Kenneth Casson Leighton lkcl at lkcl.net
Mon Aug 2 10:14:07 BST 2021


On 8/2/21, Jacob Lifshay <programmerjake at gmail.com> wrote:

> GPU code could benefit from having the semantics be where the SVP64
> predicate (either Int or CR) tells the branch instruction which CR fields
> it should use, where zero bits in the SVP64 predicate cause the
> corresponding CR fields to be ignored. Since the ignored bits cause ~ALL
> and ~ANY to no longer be redundant afaict, we will want to add them back
> in.

remember that there is both ~R30 (and ~R10) as well as ~CRbit
predicate testing, as well as being able to invert the BO bit test as
well.

i would be very surprised if, in combination with sz+SNZ, all possible
options were not covered.

l.



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