Am 18.01.2012 12:27, schrieb Mark Morgan Lloyd:
I noticed that you wanted to add a unit "i_i370" to the "compiler"
unit and to the directory "systems". This is wrong. The units listed
in the "compiler" unit are the target operating systems (e.g. Windows,
Linux, DOS), not the underlying architecture. Thus you'd only add a
"i_osvs1" (if I remember the name correctly) to that unit and
directory, but you don't need to do this know as you first need to
implement the architecture support.
This architecture support is located in the corresponding CPU unit
(e.g. ARM, PowerPC, i386, x86_64 (the latter two share the x86
directory as well)) and is included by using the "cputarg" in the unit
"compiler". This unit is located in the corresponding CPU directory.
Thus I'd suggest you to copy the directory of an architecture (e.g.
MIPS as this is a smaller and younger one) and name that "i370" (now
the unit output path I mentioned in "2" will make sense ;) ).
Perhaps now would be a good time for a core developer to add appropriate
definitions to trunk, so that anybody working on the IBM port only needs
to modify files in a directory off ./compiler.
What kind of definitons do you think of?
I myself can't help with porting FPC to a new architecture, as I
haven't done that yet (only to a new operating system target). But
AFAIK Mark Morgan Lloyd worked on the MIPS target and of course there
are compiler developers who implemented new architectures.
Bearing in mind that what I was looking at was code that had already
been working in version 1 of the compiler, which had been massaged into
some sort of shape for v2. I can claim very little credit, it was
entirely "grunt work". More relevant might be Jonas's recent work
targeting the JVM, but I suspect that the "classic" IBM mainframe
architecture is probably nearer MIPS or 68K than to JVM or a modern RISC.
By intuition I suggested MIPS as the base, because its a smaller target
in FPC (and m68k is in no shape to be used as a base...).
I don't know whether the high level code generator Jonas implemented for
the JVM branch will be of any help here.
Regards,
Sven
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