Re: [ccp4bb]: CCP4 installation on Irix notes

[Robert Campbell <rlc@groucho.med.jhmi.edu>]

On Mar 16, 2001 at 09:58:08 David Schuller wrote:
>
> On Fri, 16 Mar 2001, Kay Diederichs wrote:
> 
> > I would like to make two points about CCP4 installation on Irix.
> > 1) the -n32 ABI has a number of advantages compared to the (old and CCP4
> > default) -o32 (or -32, which is the same) ABI.
> > This runs without problems here (Irix 6.5 and compiler 7.3.1.2m), and is
> > 50-100% faster than -o32.
> 
> you do not describe the hardware you are running on.  the -n32 is
> optimised for the R10000 instruction set.  The reason the -32 option is
> still used is that it uses the R4000 instruction set, which is essential
> for those of us with older hardware(R4000, R4400).

I would like to respectfully disagree.  The -mips4 flag determines that
the R10000 instruction set is used, whereas the -mips3 flag specifies
(and here I quote from the man pages for f77 and cc):

  "Generate code using the full MIPS III (e.g. R4000) instruction set,
  and search for mips3 libraries/objects at link time.  This defaults
  to -n32 if -64 has not been specified.  On R8000- based systems this
  defaults to -64."

If you specify -n32, "Generate an n32 object.  This defaults to -mips3 if
-mips4 is not specified"


I've used -n32 frequently on an older Indigo2, which is clearly an R4000
machine.  Just don't use "-mips4" in that case!

Cheers,
Robert
-- 
Robert L. Campbell, Ph.D.               http://biophysics.med.jhmi.edu/rlc
Research Specialist/X-ray Lab Manager
HHMI/Dept. of Biophysics & Biophysical Chem., The Johns Hopkins University
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