8 May
2005
8 May
'05
4:10 p.m.
>>>> "woodelf" == woodelf
<bfranchuk at jetnet.ab.ca> writes:
woodelf> Allison wrote:
> Decmate II/III uses 6120 (PDP-8 with EMA). There
is no *nix for
> the PDP-8 and OS278 is common. FYI: VMS runs on VAX(32bit) and
> Alpha(64bit).
>
> If you can fit the game format into a 32Kword 12bit machine it's
> possible. Generally speaking there isn't a C compiler for PDP-8 I
> know of and the 4k paged addressing and very minimalist
> instruction set would be an interesting challenge. I've seen
> Fortan, Focal, Basic and even algol on an 8 but never C.
>
>
>
woodelf> The lack of local variables makes C very dificult.
Huh?
You're confusing the lack of a hardware stack with the lack of local
variables. They are not at all related.
The IBM 360/370 series doesn't have a stack, and some of its
restrictions are vaguely PDP-8 like. Nevertheless, GCC supports C
(and C++) quite nicely on those machines.
For that matter, Algol had local variables long before C was invented,
and as you pointed out, there's an Algol for the PDP-8. (Then again,
that's not a true compiler -- it compiles to an intermediate form that
looks very much like a subset of the Burroughs 5500 instruction set.)
And Unix originally appeared on the PDP-7, which you can describe
quite reasonably as an 18-bit superset of the PDP-8. (That's
historically nonsense, but as a description it fits.) Did C exist
back then, or did that wait until Unix was ported to the PDP-11? I
don't know.
Finally, CDC 6000s don't have a stack either, but the first Pascal
compiler ran on that machine. Implementing a stack on a non-stack
machine (or non-stack language like Fortran-II) is a nice elementary
Exercise for the Student.
paul