about SPARC_HAS_FPU = 1

Jiri Gaisler jiri at gaisler.com
Sat Oct 25 21:54:03 UTC 2008


There has been some new development on this issue. We have
made a small patch to gcc to avoid emitting FPU instructions for
integer code. This was actually done in the frame of using gcc for a
SPARC/LEON port of VxWorks-6.x, but is applicable to RTEMS as well.

I would suggest that we include this patch to the rtems-gcc tool chain,
and then we can compile the kernel using the regular (multi-lib) flags
rather than always using -msoft-float.

Jiri.

>>
>> Yes, i am referring to the statement
>> #define SPARC_HAS_FPU 1
>>
>> My understanding is that if the kernel is compiled with -msoft-float then we
>> have
>> #define SPARC_HAS_FPU 0 (from the header file
>> cpukit/score/cpu/sparc/rtems/score/sparc.h)
>> and then both symbols CPU_HARDWARE_FP and CPU_SOFTWARE_FP are FALSE.
>>
> [snip]
> 
> As Jiri said, SPARC_HAS_FPU should be always set, and this is
> currently not true. I guess someone should change/review that.
> 
> Aleix




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