Re: [Qemu-arm] [PATCH 2/2] target/arm: Only implement doubles if the FPU supports them

[Richard Henderson]

On 6/14/19 10:52 AM, Peter Maydell wrote:
> On Fri, 14 Jun 2019 at 18:21, Richard Henderson
> <address@hidden> wrote:
>>
>> On 6/14/19 3:44 AM, Peter Maydell wrote:
>>> @@ -173,6 +173,11 @@ static bool trans_VSEL(DisasContext *s, arg_VSEL *a)
>>>          ((a->vm | a->vn | a->vd) & 0x10)) {
>>>          return false;
>>>      }
>>> +
>>> +    if (dp && !dc_isar_feature(aa32_fpdp, s)) {
>>> +        return false;
>>> +    }
>>
>> Would it be cleaner to define something like
>>
>> static bool vfp_dp_enabled(DisasContext *s, int regmask)
>> {
>>     if (!dc_isar_feature(aa32_fpdp, s)) {
>>         /* All double-precision disabled.  */
>>         return false;
>>     }
>>     if (!dc_isar_feature(aa32_fp_d32, s) && (regmask & 0x10)) {
>>         /* D16-D31 do not exist.  */
>>         return false;
>>     }
>>     return true;
>> }
>>
>> Then use
>>
>>     if (dp && !vfp_dp_enabled(s, a->vm | a->vn | a->vd))
>>
>> ?
> 
> It would be less code, but I don't think the "are we using
> a register than doesn't exist" and the "do we have dp support"
> checks are really related, and splitting the "OR the register
> numbers together" from the "test the top bit" makes that
> part look rather less clear I think.

Fair enough.

Reviewed-by: Richard Henderson <address@hidden>


r~