Re: [PATCH] Re: [pygame] Smooth Scaling (pygame.transform.smoothscale)

[Laura Creighton <lac@xxxxxxxxxx>]

If you are on a BSD or linux system you will have a file
/proc/cpuinfo which can tell you what sort of CPU you have and
whether it has MMX support or not.  I don't know where Windows
keeps such information.  (And really old unix-and-unix-like
systems don't have this file, but they don't have MMX either,
so you are all set.)

Laura

In a message of Wed, 20 Jun 2007 19:30:07 EDT, Richard Goedeken writes:
>That's a good plan, but I haven't been able to find a good way to
>determine at compile time whether or not the compiler supports MMX.  You
>could always dump out a small test file and compile it to test for
>errors, but I was hoping to find something better like running gcc with
>a magical parameter or testing for a magical preproc definition.  Are
>you aware of any 'cleaner' ways of handling this detection?
>
>Richard
>
>
>René Dudfield wrote:
>> Hi,
>> 
>> that's good :)
>> 
>> SDL does it by compiling the mmx stuff in if the compiler supports it.
>> Then it has runtime checks to see if the cpu supports it.  SDL also
>> has a configure flag, which you can use to tell it not to even try
>> compiling mmx stuff.
>> 
>> So if the compiler doesn't support it, the C version is used.
>> If the compiler supports it, and the runtime cpu detection finds mmx,
>> then the mmx version is used.
>> 
>> 
>> 
>> On 6/20/07, Richard Goedeken <SirRichard@xxxxxxxxxxxxxxxxxxxxxxx> wrote
>:
>>> Rene,
>>>
>>> I would be willing to add the CPU detection functions but I can't thin
>k
>>> of how it could be implemented in a useful way.  The compile-time chec
>ks
>>> have to stay in because trying to compile the 64-bit code on a 32-bit
>>> architecture, or the 32-bit MMX code on a PPC or similar, will cause
>>> compile-time errors.  So it's given that if someone is running an i386
>,
>>> PPC, Sun, Arm, etc, they will get the C code.  If they're running i686
>,
>>> they'll get the 32-bit MMX, and for x86_64 they'll get the 64-bit MMX.
>>>
>>> So, the dilemma is that whatever build a user is running, the code is
>>> pretty much guaranteed to work on their CPU.  If someone is running th
>e
>>> i686 build on a 486 or something silly like that they'll probably have
>>> bigger problems.  We could allow someone to 'downgrade' and run the C
>>> code when their CPU supports MMX, but what's the point?
>>>
>>> Regards,
>>> Richard