Re: [uClinux-dev] [PATCH v2 1/6] m68k: merge mmu and non-mmu versions of muldi3

Philippe De Muyter
2011-04-20T09:55:34Z

On Wed, Apr 20, 2011 at 07:31:33PM +1000, Greg Ungerer wrote:
> On 20/04/11 19:12, Philippe De Muyter wrote:
>> On Wed, Apr 20, 2011 at 10:55:15AM +0200, Geert Uytterhoeven wrote:
>>> On Wed, Apr 20, 2011 at 10:06, Sam Ravnborg<sam@ravnborg.org> wrote:
>>>> Hi Greg.
>>>>
>>>>> +
>>>>> +#if defined(__mc68020__) || defined(__mc68030__) || \
>>>>> + Ã¡ Ã¡defined(__mc68040__) || defined(__mc68060__)
(*)
>>>>
>>>> Why use these to decide if this is MMU or not?
>>>> This code is not exposed to user-space so we can rely on CONFIG_*
>>>> symbols.
>>>> IMO the CONIFG_* symbols is easier to read/maintain.
>>>
>>> Because technically it doesn't depend on having a MMU or not, but on
>>> having
>>> the full 32-bit multiplication instruction or not.
>>>
>>> Does Coldfire-with-MMU (for which we haven't integrated the support
>>> yet) have that
>>> instruction?
>>
>> Actually, MCF547x& MCF548x (CFv4e family) are integrated but without
(*)
>> their
>> limited MMU functionality.
>>
>> freescale had even written an mmu port for 2.6.25 but has not pushed it
>> upstream. This port can be found on their site or in the openwrt
>> repository.
>
> Part of my plan with the merge of m68k and m68knommu is to make
> it easy to support the v4e parts with MMU enabled. And certainly as
> I work through cleaning the individual files up I am doing it
> with this in mind. Of course most of the code to support the v4e
> is the same no matter if you have the MMU enabled or not.
>
> I have Freescales 2.6.25 kernel, but it is really only a reference
> point for this work.
>
>> MCF547x& MCF548x do not have that instruction.
(*)
>
> Thats right. I believe the processors listed in the patch are
> the only ones that currently support the 64bit mul.

The 68340 has it also. (And I have an old linux port for this processor)

I surmise the 68360 has it also.

Philippe

(*) Greg, there must be something with your mail installation : it garbles
the messages. (or is it mine, but I noticed that only with replies from you ?)