[PD-dev] pdp's mmx support

[IOhannes m zmoelnig]

Hans-Christoph Steiner wrote:
> 
> On Oct 29, 2007, at 3:29 PM, IOhannes m zmoelnig wrote:
> 
>> Hans-Christoph Steiner wrote:
>>> Do MMX and SSE have different instruction sets?  If so, is SSE 
>>> preferred over MMX?
>>
>> yes they have different instruction sets: MMX can only handle integer 
>> values, while SSE can only handle floating point values.
>> (only SSE2 added floating point support)
>>
>> SSE2 is generally preferred over MMX since you can handle even more 
>> data with single instructions (and/or other types)
>>
>> otoh, what do we want to prove with this?
> 
> I just wanted to know whether it would be useful to enable MMX 
> instructions in a build that is tailored towards SSE2.

hmm, if you enable SSE2 you automatically enable MMX.

> I believe I just wanted default builds to not use SSE2 so it could be 
> widely deployed.  Hopefully you didn't remove that code (I doubt you did 

you have to explicitely tell configure that you do want to use SSE2
(as opposed to checking whether the compiler supports it and use it 
automatically, as is with MMX)

fa.r
IOhannes