"Naveen H. S" <navee...@kpitcummins.com> wrote:
> Software floating point(libgcc) routines were implemented for SH in the
> following links:-
> http://gcc.gnu.org/ml/gcc-patches/2006-09/msg00063.html
> http://gcc.gnu.org/ml/gcc-patches/2006-09/msg00614.html
> http://gcc.gnu.org/ml/gcc-patches/2004-08/msg00624.html
>
> There were some discussions regarding the testing of these routines.
> We had briefly tested those routines and found that they did not have
> any major issues.
> http://gcc.gnu.org/ml/gcc-patches/2006-10/msg00791.html
> Please let me know whether these routines can be used in SH toolchain.
SH currently uses fp-bit.c implementation of soft fp which is
known as a rather inefficient one. PowerPC uses a more efficient
soft-fp derived from glibc. Other targets like arm, ia64, sparc
and also some new targets use it. Please see config/*/t-*softfp
and config/*/sfp-machine.h. We can expect the best performance
from Joern's assembly soft fp, but in general the maintenance of
hand crafted assembly codes will be hard.
If I remember correctly, there were some arguments for this
target specific one vs. generic one when soft-fp was introduced
in gcc. It would be better to try soft-fp on SH and see numbers
with current fp-bit, soft-fp and assembly one.
If soft-fp is yet too inefficient for you, you can free to propose
a complete and regtested patch for SH assembly soft fp against
trunk. The original Joern's patch touched not only SH specific
part but also the generic part of the compiler. The revised patch
is needed to test it for various targets too.
Regards,
kaz
