Re: [PATCH] target/s390x: Fix CC set by CONVERT TO FIXED/LOGICAL

[Richard Henderson]

On 6/28/21 5:58 AM, Ulrich Weigand wrote:
> > > helper.h:DEF_HELPER_FLAGS_3(clgdb, TCG_CALL_NO_WG, i64, env, i64, i32)
> >
> > This won't work reliably.  You're writing to a tcg global inside of
> > a function that says that it won't.
>
> I missed that, sorry.  That problem can be fixed by changing the above
> line to something like:
> DEF_HELPER_3(clgdb, i64, env, i64, i32)
> right?

Yes.

> In any case, the current implementation already has two helpers, and
> I initially tried to keep that, by using a different second part to
> correctly compute CC.  But this ran into the problem that I didn't
> see any way to detect the fact that the conversion operation had run
> into one of the special cases in the second helper, without re-doing
> the whole conversion a second time.  Is there any way to pass
> information between the two helpers (without running again into the
> same qemu global state updating problem)?

Don't clear out env->fpu_status.float_exception_flags in handle_exceptions.  Wait until 
we're actually done with the data.


r~