Re: Two questions about compiler design

Scott Moore <samiam@moorecad.com> wrote:
>"Isaac" <isaac@latveria.castledoom.org> wrote
>
>Commonly a reference to the intermediate format used in Wirth's
>porting package for Pascal. See my page on it at:
>
>http://www.moorecad.com/standardpascal/p4.html
>
>Its basically just the intermediate for a Pascal, it seems to
>garner attention because it was the first widely used "virtual
>machine" solution, and even had a hardware processor specifically
>created for it.


I don't think so. Ocode was somewhat earlier, and I have some vague
memories of others. If you count total implementations (alive and
dead), I think that you will find that Ocode is still a long way ahead
of Pcode. BCPL was incredibly widely ported, because it was often
ported as a basis for specific packages (Cambridge LISP, among several
others).


Wirth caught the zeitgeist in a way that Richards didn't, which is why
the public perception of Pascal being more widely available than BCPL
comes from. But I don't think it was so and, because only some
Pascals have used Pcode but almost all BCPLs have used Ocode, I doubt
very much that Pcode ever got near Ocode in number of ports.


However, Pascal overtook BCPL in terms of LIVE implementations some
time ago. I can't guess which would be ahead in historical ones.




Regards,
Nick Maclaren.

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