[Ffmpeg-devel] bfin cpu specific build options

[Marc Hoffman]

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On Feb 21, 2007, at 3:03 PM, Marc Hoffman wrote:

>
> On Feb 21, 2007, at 9:28 AM, M?ns Rullg?rd wrote:
>
>>
>> Guillaume POIRIER said:
>>> Hi,
>>>
>>> On 2/21/07, M?ns Rullg?rd <mans at mansr.com> wrote:
>>>>
>>>> Marc Hoffman said:
>>>>> Not sure if this needs an explanation.
>>>>>
>>>>> Index: configure
>>>>> ================================================================== 
>>>>> =
>>>>> --- configure        (revision 8047)
>>>>> +++ configure        (working copy)
>>>>> @@ -1329,6 +1329,11 @@
>>>>>          sparc64)
>>>>>              add_cflags "-mcpu=v9"
>>>>>          ;;
>>>>> +        bf*) #bf531 bf532 bf533 bf561 bf5xx all get this config
>>>>> +            add_cflags "-mfdpic"
>>>>> +            add_ldflags "-mfdpic"
>>>>> +            add_ldflags "-Wl,--defsym,__stacksize=0x40000"
>>>>> +            ;;
>>>>
>>>> The ;; indentation is inconsistent.  Otherwise OK.  I don't know  
>>>> blackfin,
>>>> so I assume the options are correct.
>>>
>>> I'm curious about the necessity of specifying stack size value. Is
>>> this meant to optimize better, or is it necessary to just get ffmpeg
>>> to compile and run correctly?
>>
>> That flag defines the symbol __stacksize as having the address,  
>> not value,
>> 0x40000.  Presumably, there is a declaration such as extern long  
>> __stacksize;
>> in some header, but no actual definition in any source file.  One  
>> can only
>> hope that the loader actually store the stack size at this location.
>
> To answer the stacksize issue, the ffmpeg allocates the audio  
> buffer on the stack and that just happens to be 128k which is the  
> default stack size.  As Mans points out stacksize is just a symbol  
> which is defined by the liner environment.
>
> Do you need me to fix the indentation?
>

I guess here is the correct indentation:

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