On Fri, 10 Sept 2021 at 16:40, Richard Henderson <
richard.henderson@linaro.org> wrote:

> On 9/10/21 3:36 PM, Philipp Tomsich wrote:
> > Richard,
> >
> > Did you have a chance to consider what to do with clzw?
> > I would prefer to avoid the extra extension instructions and change the
> implementation
> > (and would update the commit message to provide more context), but if
> you insist on
> > setting 'ctx->w' I'll just have the extra extensions emitted than delay
> this series further…
>
> I don't mind not setting ctx->w, but bear in mind that UXL is going to
> automatically set
> this flag when executing RV32 on RV64.  That's why I have written a tcg
> patch set to
> eliminate unnecessary sign-extensions.
>

Ok, thanks!  Updated patches follow, once all test workloads have run…

Just wondering regarding the UXL-comment: the clzw instruction will be an
illegal encoding for RV32 (the w-form instructions are present on RV64
only), so it should never be encountered in a RV32 instruction stream.  Did
you mean that clz (the instruction operating on xlen-registers) would have
ctx->w set for RV32 executing on RV64 ... or am I missing something
fundamental?

Philipp.