Anyone got a PACE system? Or software, docs?
eric at brouhaha.com
Wed May 13 01:52:12 CDT 2009
I'm interested in talking to anyone who has or had a National
Semiconductor PACE or INS8900 system, or documentation or software for one.
In order to have something halfway interesting to run on the homebrew
IMP-16 system John List designed and built, I decided to start from PACE
software, since the PACE architecture is derived from (but not
binary-compatible with) the IMP-16, which itself was inspired by the
Data General Nova.
A few years ago a friend gave me a copy of the fig-FORTH listing for the
PACE, which turned out to be missing a page. The listing is on
Bitsavers, but a complete listing is now available on the fig-FORTH
implementations page on forth.org:
Over the course of the last week, I typed in the fig-FORTH listing (both
source and object code), wrote a PACE cross-assembler, assembled
fig-FORTH and compared the generated object to what I typed in, fixed
the errors, wrote a PACE simulator, and fixed the fatal bug in the "U/"
word of the fig-FORTH listing. (Maybe no one other than the author ever
actually ran PACE fig-FORTH?) Now that it's working I've just started
trying to translate it for the IMP-16, which doesn't have the RADC and
SUBB instructions of the PACE, and which has somewhat different shift,
rotate, and flag instructions.
Google doesn't turn up much about the PACE other than the few manuals
and datasheets already on Bitsavers. I know that a paper tape based
resident assembler existed, as well as a disk operating system with a
resident assembler. There may have also been a BASIC interpreter.
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