Re: Does -march=r5000 imply HAVE_64BIT_GPRS?

[Thiemo Seufer <ica2_ts at csv dot ica dot uni-stuttgart dot de>]

Ian Lance Taylor wrote:
> Eric Christopher <echristo@redhat.com> writes:
> 
> > > Is command line compatibility to other assemblers an issue?
> > 
> > Not that I know of - though I'd prefer if Ian were to speak up here and
> > let me know if it is the case.
> 
> All MIPS assemblers take -mips1, -mips2, etc., to select the ISA.
> Other than that, I don't think there is any compatibility issue.  Most
> existing MIPS assemblers are of course just for a particular host, and
> don't worry about many different CPU options.
> 
> If anybody has access to a current Irix system, it might be
> interesting to see the range of options the assembler accepts there.

This is what the Manpage says:

ISA/ABI COMMAND LINE OPTIONS
     The following options control the choice of ABI and Instruction Set
     Architecture (ISA).

     -o32 or -32    Generate a 32-bit object.  This defaults to -mips2 if
                    -mips1 is not specified.  This is the default when
                    compiling on any non-R8000 based system, if no default
                    specification file is present.  See the o32(5) man page
                    for details.

     -64            Generate a 64-bit object.  This defaults to -mips4 if
                    -mips3 is not specified.  This is the default when
                    compiling on any R8000 based system, if no default
                    specification file is present.  See the Defaults
                    Specification Files subsection at the end of this man
                    page for details.

     -n32           Generate an n32 object.  This defaults to -mips3 if
                    -mips4 is not specified.

     -mipsn         Determine architecture type. n can be one of the
                    following values:

                    1    Generate code using the instruction set of the
                         R2000/R3000 RISC architecture, and search for
                         mips1 libraries/objects at link time.  This
                         defaults to -o32.

                    2    Generate code using the MIPS II instruction set
                         (MIPS I + R4000 specific extensions), and search
                         for mips2 libraries/objects at link time.  This
                         defaults to -o32.

                    3    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.

                    4    Generate code using the full MIPS IV instruction
                         set which is supported on R10000, R5000 and R8000
                         systems.  Also search for mips4 libraries/objects
                         at link time.  This is the default on R8000
                         systems.  This defaults to -n32 if -64 is not
                         specified.  On R8000-based systems it defaults to
                         -64.

AFAIK SGI never built Machines with R6000, so MIPS II is called a
"R4000 specific extension".


Thiemo