check mips abi x linker emulation compatibility

[Maciej W. Rozycki]

On 20 May 2003 cgd@broadcom.com wrote:

> Uh, "and mips64 means mips3 isn't confusing"?  8-)

 It is, but I think that meaning (=any 64-bit MIPS CPU) predates the
MIPS64 ISA, so the ambiguity is an ISA creators' fault. ;-) 

> I don't know that there's any reason to support an abi=64 default set
> of tools, since really, people shouldn't be using abi=64 except with
> certain extreme cases IMO.  (more space for no gain.)

 (N)64 gives you the comfort of not needing to worry a program will fail
when a 31-bit limit gets hit.  This means any program that requires 64-bit
VM, such as one allocating a lot of memory (typically with anonymous
mmap()) or using mmap() on files that can exceed 2GB.  For a workstation
or server type of environment the loss from a somewhat worse performance
may be negligible compared to a risk of a need to recompile software at
the time it fails, which is usually the worst possible moment.

 You can also use (n)64 as a debugging tool to find and fix unportable
code, such as one assuming sizeof(int) == sizeof(void).  That's a
secondary use, of course, but still nice. 

-- 
+  Maciej W. Rozycki, Technical University of Gdansk, Poland   +
+--------------------------------------------------------------+
+        e-mail: macro@ds2.pg.gda.pl, PGP key available        +