[fpc-devel] Re: System 370: Episode 3. Addressing and it's limits Part One!

Mark Morgan Lloyd markMLl.fpc-devel at telemetry.co.uk
Fri Feb 10 21:20:15 CET 2012

steve smithers wrote:

>> If Hercules is configured as an S/390 to keep the guest operating system 
>> (e.g. Linux) happy, is it possible to validate that a binary is 
>> completely safe to run on an S/370, i.e. contains no 390-specific features?
> I'm not exactly clear on what you are asking.  You could turn off the 390
> features on Hercules and see if it crashes, or you could ensure you don't
> generate thme by using some compiler switch, or you could remove the macros
> required for the IBM Assembler to support the mods, they will cause assembly
> errors.  Or what ...?

But assuming that an initial port is to Linux, you need Hercules to 
provide S/390 features or the operating system won't run. The way I read 
it, if you're also targeting classic operating systems such as VM/370 
then the only way to prove that the code generation is 370-safe is to 
run the code on a (simulated) 370: there's no way of testing compliance 
at an earlier stage.

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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