[libre-riscv-dev] [isa-dev] 3D Open Graphics Alliance

[lkcl]

On Tuesday, August 13, 2019 at 5:58:34 AM UTC+1, Jacob Lifshay wrote:
>
> On Mon, Aug 12, 2019, 03:26 lkcl <luke.l... at gmail.com <javascript:>> 
> wrote:
> >
> > On Monday, August 12, 2019 at 2:31:44 PM UTC+8, Jacob Lifshay wrote:
> > > So, you overestimated the number of immediate bits needed by quite a 
> lot.
>
> I was assuming a separate swizzle opcode instead of swizzle on every op. 
> if we want to combine them, we can implement that using macro-op fusion.
>

found the (prelimilary, draft) page with some ideas under consideration:
https://libre-riscv.org/simple_v_extension/specification/mv.x/
 
i like the macro-op fusion concept.

the other alternative: VBLOCK context.  [for readers not familiiar with 
VBLOCK, the draft spec is 
here: https://libre-riscv.org/simple_v_extension/vblock_format/]

concept: mark a register as "if you use that register, within this current 
VBLOCK, its use indicates a desire to change the behavior of the current 
instruction".

register tagging, in other words.

the only thing is, fitting a third context (beyond the vector table format 
and the predicate table format) will need a redesign, or to go into the 
192+ bit RV opcode format.

l.

>