Re: [gforth] Running Gforth on Mips64el

[Anton Ertl]

On Sat, May 24, 2014 at 12:47:15PM +0200, Bernd Paysan wrote:
> Am Samstag, 24. Mai 2014, 07:05:32 schrieb David Kuehling:
> > Hi,
> > 
> > just compiled Gforth head in a Mips64el Debian Sid system (actually a
> > chroot boostrapped from here [1]), and the result seems to work.  I'm
> > actually surprised, given that 64-bit MIPS OS are extremely rare, so
> > this may have not been tested at all before.  (BTW Gforth package is
> > missing from the Mips64el port, maybe the older Gforth used in Debian
> > does have problems with Mips64).
> 
> Anton had used some Ultrix machines during the early development of Gforth, 
> so 
> unless we don't break anything, MIPS64 should work fine (and has worked very 
> early on).

Ultrix was only ever 32 bit (even on the machine with an R4000 that we
had).  Later I tested on IRIX (mipseb), but I doubt if this was
MIPS64 (even though the CPU was).

Gforth 0.6.2 ran on hardware like AMD64 and IA-64 that it had not been
tested on before, and that portability should be still there.  The
threading model needs no machine-dependent stuff, and even dynamic
superinstructions need relatively little (and are disabled on unknown
platforms).

> > What bugs me is that there is no way to determine the ABI of the
> > underlying OS from within Gforth.  Typeing MACHINE TYPE just gives
> > 'mips' on both O32 and N64 ABIs.  Gforth' MIPS assembler needs to know
> > the ABI as register aliases differ by ABI.  I could patch it to just
> > check CELL-size and assume N64 if CELL=8 and O32 if CELL=4, but then
> > it'll still fail on N32 MIPS systems (and O64 systems, though these
> > should be extremely rare or non-existent).
> 
> What does config.guess return on these different machines?  I see only mips 
> or 
> mips64, which we both turn to mips (actually, we should keep mips64 as is), 
> but I have no idea how to distinguish between O32 and N32.

We could have a variable ABI-NAME or somesuch, but how to set it
portably?

> > If somebody wants to do Mips64-specific tuning to Gforth, I can hand out
> > login access to the machine in question.

Might be interesting when I test the next release.  I'll contact you
then.

- anton