Re: Disabling and re-enabling extensions
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I thought there was already a speced requirement that, at reset, all extensions are enabled.:
"At reset, the Extensions field shall contain the maximal set of supported extensions, and I shall be selected over E if both are available."
And then there are the corner cases: if there are no misa bits for subsets (e.g Zbb, Zv<whatever>), then they can't be enabled or disabled.
So, why should misa. bits for the full extensions allow enabling/disabling?
What does it mean for misa.G to be enabled or disabled? misa.I ?(if misa.E isn't also present)?
Has anyone identified use cases for turning extensions on and off? (as opposed to FP-like disabled state to save power).
Has anyone ever implemented RW misa bits?
IF not: why not just require those MISA bits to be RdOnly?
On Thu, Sep 10, 2020 at 10:44 AM Greg Favor <gfavor@...> wrote: