On Wed, Jul 8, 2020 at 9:25 AM Richard Henderson
<richard.hender...@linaro.org> wrote:
>
> On 7/6/20 4:47 PM, Max Filippov wrote:
> > +float64 HELPER(add_d)(CPUXtensaState *env, float64 a, float64 b)
> > +{
> > + set_use_first_nan(true, &env->fp_status);
> > + return float64_add(a, b, &env->fp_status);
> > +}
> > +
> > float32 HELPER(add_s)(CPUXtensaState *env, float32 a, float32 b)
> > {
> > + set_use_first_nan(env->config->use_first_nan, &env->fp_status);
> > return float32_add(a, b, &env->fp_status);
> > }
>
> I think you can do better than to set the use_first_nan flag before every
> operation.
And it was better, until I found that the rules for float64 are a
bit... peculiar.
> E.g. the translator could remember the previous setting within the TB, only
> changing when necessary. E.g. if env->config->use_first_nan, then set it
> during reset and never change it again. Similarly if DFP is not enabled.
This thought crossed my mind too, but then set_use_first_nan only
sets one variable in the float_status and gets inlined.
Is it worth the trouble?
--
Thanks.
-- Max
