[Libre-soc-dev] v3.1B prefix

[Jacob Lifshay]

On Sun, Dec 13, 2020, 14:17 Luke Kenneth Casson Leighton <lkcl at lkcl.net>
wrote:

> well, we are likely down the road to still need to put 16-bit
> instructions and an 11-bit SV Prefix together so as to create a 32-bit
> Vector-only ISA subset.  this will be the only way we will be able to
> then do double-swizzled operations without having massive
> macro-op-fused sequences.


I'd have to do some analysis, but I expect single-swizzled operations to be
somewhere between 2x and 10x (or more) as common then double-swizzled
operations, so I think we'd be fine without special double-swizzled
instructions.

Jacob