[fpc-devel] On a port of Free Pascal to the IBM 370

[Tomas Hajny]

On Wed, January 18, 2012 10:15, michael.vancanneyt at wisa.be wrote:
> On Wed, 18 Jan 2012, Michael Schnell wrote:
>
>> AFAI learned:
>> I suppose the code generator should be doable, regarding that there
>> already
>> are several supported CPUs. At least a working compiler might come into
>> existence in a decent amount of time, adding optimizations is another
>> project.
>>
>> OTOH I suppose that a porting the RTL to a mainframe OS will not be easy
>> and
>> without this the compiler is quite useless.
>
> I do not think it is more difficult than any other OS.

...except for the EBCDIC stuff, because the common parts of our RTL assume
ASCII in many places (most of them probably not that difficult to fix by
adding some platform specific constants changing the behaviour from ASCII
only to consider EBCDIC too, but scattered around many places and thus
difficult to find). That doesn't mean it shouldn't be doable, of course,
it will just require debugging even parts which didn't have to be touched
during ports to other operating systems.

Still, starting with the Linux for S/390 (or are S/390 and S/370
completely different animals?) as suggested by Mark would be probably a
very good idea to avoid having to tackle both a different HW platform and
a different OS at the same time (the Linux port to S/390 apparently uses
ASCII according to what I found on Internet). Obviously, the OS may follow
once the new HW platform is in working state.

Tomas