RE: [patch] Update MIPS DSP madd, maddu, msub, msubu, mult, multu

["Fu, Chao-Ying" <fu at mips dot com>]

Richard Sandiford wrote:
> "Fu, Chao-Ying" <fu@mips.com> writes:
> >   Here is the GCC patch to move 
> madd/maddu/msubu/msub/mult/multu from MIPS DSP r2 to DSP r1.
> > Note that the Binutils patch has been committed to FSF 
> binutils mainline.
> > http://sourceware.org/ml/binutils/2010-10/msg00331.html
> > http://sourceware.org/ml/binutils/2010-10/msg00424.html
> >[...]
> >   Any feedback?
> 
> Looks good.  My main concern is that the patch as-is introduces
> a dependency on bleeding-edge binutils.  That's not such a problem
> for cases where the user has explicitly called a 
> __builtin_*() function
> in rev1 code, because that simply didn't work before.  But it 
> is a problem
> for cases where the compiler is automatically using these 
> instructions.
> You'll get assembler errors when compiling ordinary C code, 
> which never
> looks good.
> 
> I think we need to add a configure-time check to see whether the
> assembler has your patch.  There are quite a few existing examples
> of this.  Then we should introduce a new macro such as:
> 
>     ISA_HAS_DSP_MULT
> 
> This macro can be defined to ISA_HAS_DSP if the assembler has your fix
> and ISA_HAS_DSPR2 otherwise.
> 

  I will update my patch to have a configure-time check and ues ISA_HAS_DSP_MULT.
Thanks a lot!

Regards,
Chao-ying