Paul Robinson wrote:
> I sometimes wonder if programmers at the Rite Aid or Walgreens drug
> store chains use CVS. (CVS is a competing drug-store chain in the US
> as well as the name of a source-code repository system.) Oh well, it
> was a better joke when I thought of it.
I'd remind you that several other manufacturers (including Burroughs and
ICL) used the IBM 029 card punch, even if they typically put their own
logo on it.
> On the pages on the Free Pascal Wiki I'm writing on my attempts to
> port the Free Pascal Compiler over to the IBM 370 series machine
> (known now as zSystem),
That seems an eminently good idea, since it's about the only major
architecture (with the arguable exception of the Itanic) that FPC
doesn't target.
> with the initial target being an IBM 370 on OS/VS1,
Why not start with Linux? it's a bit more accessible for the rest of us,
and you'll be able to refer to existing RTL source.
> * It's Big Endian (I believe the PDP-11 minicomputer is also.)
As are SPARC and PPC, both of which FPC supports.
> * The most you can access at any one point from a register is 4K,
> whether that's a branch in code, or a piece of data. [...] Only
> tables are available, in-line constants are generally not (this is
> not exactly true, but is close)
I'd suggest reviewing the "Porting GCC to the IBM S/390 Platform" paper
that I've cited on http://wiki.lazarus.freepascal.org/ZSeries, and
selecting a base system that does allow inline constants. I think it's
pretty unlikely that anything's left in (commercial) operation that's
older than this, and the Hercules emulator (see for example
http://wiki.lazarus.freepascal.org/Qemu_and_other_emulators#Debian_zSeries_Guest_using_Hercules)
obviously supports the newer facilities.
> * It's internal character set is EBCDIC, not ASCII. Also, the
> character set is not continuous along the alphabet, e.g. doing a test
> on ['a'..'z'] or ['A'..'Z'] will fail because it will pick up other
> non-alphabetic characters.
Again, I'd suggest starting off targeting hardware and OS that's happy
with ASCII.
--
Mark Morgan Lloyd
markMLl .AT. telemetry.co .DOT. uk
[Opinions above are the author's, not those of his employers or colleagues]
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