longcall probelm (RE: was MVME2304 Exception 3 )

Till Straumann strauman at slac.stanford.edu
Fri Sep 19 15:39:28 UTC 2003


Kate.

Why would you want the -mlongcall flag? Do you anticipate ever needing 
more than
32M of text/code space?? Note that -mlongcall incurs both, a speed and 
space penalty.

If you don't like the SBRK workaround, a cleaner solution would have the 
BSP reserve
a dedicated memory region close to the system (low) memory for CEXP (or 
any other
loader) to use for ".text".

-- Till

Kate Feng wrote:

>Till Straumann wrote:
>
>  
>
>>Try the attached patch - it provides SBRK. This should enable you to
>>load modules until the first 32M are exhausted. SBRK will then release the
>>rest of your memory to the system but after that happens modules cannot
>>be loaded anymore.
>>
>>    
>>
>
>Thanks Till.
>
>My wish  for the long term is that :
>it will be nice  if RTEMS can patch up the rs6000.c and related  files so that
>the  rtems-gcc cross compiler support the  -mlongcall  flag, which was  already
>supported in vxWorks 2.95.3 ppc cross-compiler.  Except, at this point, I am not sure
>yet  if the longcall  compiling option has to be restricted to  SYSV/EABI
>calling convention (  http://gcc.gnu.org/ml/gcc-patches/2001-02/msg00236.html)
>
>Kate
>
>
>
>  
>





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