Re: [Qemu-ppc] [Qemu-devel] [RFC 5/6] target-ppc: add modulo word operations

[Nikunj A Dadhania]

Richard Henderson <address@hidden> writes:

> On 07/18/2016 10:38 AM, Nikunj A Dadhania wrote:
>> David Gibson <address@hidden> writes:
>>
>>> [ Unknown signature status ]
>>> On Tue, Jul 12, 2016 at 11:33:21PM +0530, Nikunj A Dadhania wrote:
>>>> Adding following instructions:
>>>>
>>>> moduw: Modulo Unsigned Word
>>>> modsw: Modulo Signed Word
>>>>
>>>> Signed-off-by: Nikunj A Dadhania <address@hidden>
>>>
>>> Hrm.. any reason you're not using the TCG inbuilt remainder ops
>>> (tcg_gen_rem_i32() etc.)?
>>
>> I have an updated version with me which uses inbuilt ops, i was searching
>> for modulo expressions, which I didn't find, so wrote. Found later that
>> it is called tcg_gen_rem. Will send in the next version.
>
> It would probably be better to use helper functions for both div and mod, 
> because of the branches required.
>
> C.f. target-arm/helper-a64.c, helper_sdiv64 et al.

What is the thumb rule to implement it has helper?
As I am implementing other instructions as well.

One as you suggested many branches.

Regards
Nikunj