Forth for RSTS

[Paul Koning]

> On Jan 3, 2016, at 4:56 PM, Paul Koning <paulkoning at comcast.net> wrote:
> 
> ...
> This Forth implementation is a port of Fig-FORTH by John S. James, with some RSTS-specific magic added.  I just realized the file header says that it is in the public domain, so I suppose I should post the source...

Done.  Thanks to Al Kossow, it now lives on Bitsavers, in bits/DEC/pdp11/forth/forth.mac

This is the RSTS run-time system, from V9.6 and later.  I haven't tried building it on older versions; the comments say it works back to V7.2.  I don't remember why that version is mentioned.  Run time systems existed before then, though a few details did change over time.

The original version was for RSX and RT-11.  I did the RSTS port, and Kevin Herbert added some more stuff to it later on.  The biggest change is to make the vocabulary machinery match the ANSI Forth 83 standard, which allows for lots of separate vocabularies and arranging their search order.  This was needed to allow SDA to define a set of 32 bit replacements for the standard (16 bit) arithmetic operators of native Forth, without getting itself all confused.

Build instructions are in the comments near the top of the file.  There's very little to it.

Enjoy.

	paul