i370 port - 3.4.6 to 4.4 upgrade attempt

[Paul Edwards]

> I can see one significant change: the GCC middle-end now no
> longer supports base-16 floating point at all.  The old i370
> port was the only user of this feature, and some time after
> the port was removed, the middle-end support was removed as
> well in order to simplify floating-point handling code.

Hmmm.  Well I don't know anything about floating point.

Thanks very much for all your comments.  I will see what
difference that makes.

> Note that I'd expect that with the above obvious issues fixed,
> you may well run into additional problems in moving the port
> forward ...  At some point, it will be necessary to be able
> to debug the back-end and resolve problems.

Ok, well what I did in the original (3.2) port was to ANSIfy it and
then use different debuggers (Borland, Watcom) on my Windows
box.  I'll see what I can come up with this time.

> Overall, I still think that adding HLASM support to the s390
> back-end would probably be a simpler task ...

Well in that case, maybe now is the time to be doing exactly
that.  I could make 3.4.6 the last of the i370 ports.

Can you tell me what is required to convert s390, which has a
very alien assembler output, into hlasm?

And that brings me to another question.  The i370 hlasm port
uses tabs in every instruction to separate the instruction and
operand.  This is not valid in hlasm.  In order to get around
this, I ended up doing a #define for putc etc to channel everything
through my own routine which converted those tabs into an
appropriate number of spaces.  I suspect there's a neater way
to do things, but I never stumbled across that in my travels.

Thanks.  Paul.