Re: [PATCH v2 01/26] s390x/tcg: Fix FP CONVERT TO (LOGICAL) FIXED NaN handling

[David Hildenbrand]

On 01.06.21 23:27, Richard Henderson wrote:
> On 5/17/21 7:27 AM, David Hildenbrand wrote:
> > @@ -634,6 +664,9 @@ uint64_t HELPER(clfxb)(CPUS390XState *env, uint64_t h, 
> > uint64_t l, uint32_t m34)
> >   
> >       s390_restore_bfp_rounding_mode(env, old_mode);
> >       handle_exceptions(env, xxc_from_m34(m34), GETPC());
> > +    if (float128_is_any_nan(make_float128(h, l))) {
> > +        return 0;
> > +    }
>
> I wonder if handle_exceptions should return s390_exc.
> Then you can test
>
>     exc = handle_exceptions(...);
>     if (unlikely(exc & S390_IEEE_MASK_INVALID)) {
>       ret = 0;
>     }
>     return ret;

I'll give it a thought if that makes things easier.

> > +++ b/target/s390x/vec_fpu_helper.c
> > @@ -326,6 +326,9 @@ void HELPER(gvec_vcdlg64s)(void *v1, const void *v2, 
> > CPUS390XState *env,
> >    
> >    static uint64_t vcgd64(uint64_t a, float_status *s)
> >    {
> > +    if (float64_is_any_nan(a)) {
> > +        return INT64_MIN;
> > +    }
> >        return float64_to_int64(a, s);
> >    }
> >    
> > @@ -349,6 +352,9 @@ void HELPER(gvec_vcgd64s)(void *v1, const void *v2, CPUS390XState *env,
> >    
> >    static uint64_t vclgd64(uint64_t a, float_status *s)
> >    {
> > +    if (float64_is_any_nan(a)) {
> > +        return 0;
> > +    }
> >        return float64_to_uint64(a, s);
> >    }
>
> You do still need to raise invalid, as far as I can see.

Good point, so maybe


uint64_t ret = float64_to_uint64(a, s);

/* Note: check after converting to properly raise exceptions. */
if (float64_is_any_nan(a)) {
        ret = 0;
}
return ret;


to minimize manual handling?

--
Thanks,

David / dhildenb