Re: [PATCH 09/21] target/xtensa: add DFP option, registers and opcodes

[Richard Henderson]

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.

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.


r~