Re: Smstateen for Zcmt
Greg, you said:
The spec for Msstateen says:
It sounds like this is that rare case: Smstateem enable bit is required because they are incompatible,
So it must control both the access to the CSRs and all instructions defined by that extension - even if some particular op doesn't change processor state (beyond Rd)
Then, why is a custom enable/disable required ?
(and possibly a bit more complicated: if misa.D, Smstateen.Zcmt can't both be set, so setting one must clear the other)
OR is that extra bit of functionality what makes it custom - though that would be the requirement of any extension that conflicts with other extension,
which should probably be made part of the spec so we don't go through this exercise every time it happens.
Though I supposed I'd be happy if it never happens again...
On Mon, May 16, 2022 at 12:32 PM Greg Favor <gfavor@...> wrote: