Re: [PATCH v2 2/6] target/riscv: hardwire mstatus.FS to zero when enable zfinx

[Weiwei Li]

在 2022/1/2 上午3:46, Richard Henderson 写道:
> On 12/31/21 9:55 PM, Weiwei Li wrote:
> > > This shouldn't be necessary because it should never have been set.
> > Yes, I think so. However, I have a question about MSTATUS_MIE and 
> > MSTATUS_MPRV, will they be set before cpu reset?
>
> Yes, via warm reset.
Thanks. I'll fix this later.
> > > I would think it would be more correct to have a positive test for 
> > > RVF, rather than a negative test for ZFINX?
> > It may  deviate from the original value of mstatus_mask with a 
> > positive test for RVF.
>
> Oh, you mean misa_ext?  Hmm.  Interesting point.
>
> When F extension is not implemented, FS is either hardwired to zero 
> (without S-mode) or optionally zero.  So this looks like an existing 
> bug to be fixed.
OK.  There is similar logic in write_mstatus and .  I'll fix it too.

I'll also update write_frm,  write_fflags and write_fflags to have a 
positive test for RVF .

> r~