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

[lkcl]

On August 4, 2021 5:45:19 PM UTC, lkcl <luke.leighton at gmail.com> wrote:

>i've therefore put re-purposing of AA as Rc back.in, sigh.

i just realised / remembered that there are some spare bits in the RM EXTRA2/3 area that can be used rather than make life hell (and create critical dependencies) in RM MODE.

for other instructions including LD/ST the EXTRA2/3 area is often entirely taken up, so trying to reuse it for Mode bits is inappropriate.

however Branches are so specific (only 2) that we *know*, from examining the register profile of Branches, that they will not use the high area of EXTRA2/3, or in fact the ELWIDTH area either (which may be a better choice, EXTRA2/3 is quite complex decoding, and adding extra MUXes into it is not something done lightly)

i will rework things today.

l.