[RFC PATCH v5] RISC-V: Add support for the Zfa extension

[Palmer Dabbelt]

On Thu, 29 Jun 2023 08:49:16 PDT (-0700), jeffreyalaw@gmail.com wrote:
>
>
> On 6/29/23 09:37, Palmer Dabbelt wrote:
>
>>>> > So my understanding is that this needs to wait for ratification and is
>>>> > not blocked by the mentioned PR.
>>>> Is there something special about Zfa that makes it desirable to wait for
>>>> ratification as opposed to standard practice of gating things as the
>>>> specs get to a Frozen state?
>>>
>>> Not to my knowledge.
>>
>> Waiting for ratification is probably a bad idea, there's really no way
>> to schedule around it.  That's a big part of the reason we've just
>> waited for frozen.
> Exactly.  ISTM that frozen is the right point to trigger.
>
>>
>> IIUC we're just waiting on the assembler syntax to be accepted, it's not
>> an ISA problem right now.
> And I think enough of it is settled that we can move forward. If RVI
> changes the set of forms allowed, then we can adjust.

Works for me.  So

Acked-by: Palmer Dabbelt <palmer@rivosinc.com>

Presumably someone's actually looked at the code?  If not I can look 
over it...

>> It's not all that hard to just add more flavors of assembler syntax
>> later, so maybe we just merge this and stop bothering to wait for all
>> these other non-ISA specs to resolve?
> I'd be more worried about them removing a supported form as that would
> result in hand-coded assembly might needing to be adjusted.  But I
> wouldn't expect there's much hand-coded Zfa code out there.

Historically we've just kept whatever is released as a compatibility 
mechanism and then added stuff, but I guess we can sort that out when it 
comes to it.

>
> Jeff