May 2009 Meeting Notes

Compiled by Dave Jaffe

Contributions from Kevin Appert and others

10:00

Coffee and a Chat

10:15

eForth in C - CH Ting
"I will continue my discussion of implementing eForth in C. The interpreter is already done, using a C execution pointer table. I am rearranging the byte code to build a byte code compiler. I think a byte code compiler will be able to compile the high level Forth words in the C system as well as compile new words interactively."

11:40

Lunch
Lunch on-campus. To avoid the "noon lemming effect", we'll leave a little early.

13:00

Introductions, Announcements, Rumors, Random Access

13:30

FIG-Forth on a National Semiconductor PACE Microprocessor - Eric Smith
Eric is attempting to port PACE FIG-Forth to the National Semiconductor IMP-16. IMP-16 was National's earlier multi-chip 16-bit microprocessor, introduced in 1973. The PACE architecture was similar to the IMP-16, and the IMP-16 in turn was somewhat inspired by the Data General Nova.

"I've been an occasional user of Forth since 1978 or so. Before now I've never studied the internals of a Forth implementation, but now I'm groveling around in the bowels of FIG-Forth."

"Over the last four days, I've written an assembler and simulator for the old National Semiconductor PACE microprocessor (the first single-chip 16-bit microprocessor, introduced in 1975), and trying to get the published PACE FIG-Forth working. I've found that the published PACE FIG-Forth contains at least two nasty bugs that prevent it from working correctly at all. The U/ word as written does not work, which prevents numeric input and output from working. I fixed that, and now have found that defining new words with colon doesn't work. CREATE creates the word, and colon fills in the PFA, but the CFA of the new word isn't getting set properly. Possibly PSCODE is broken. This makes me wonder whether anyone other than the author ever used PACE FIG-Forth at all. Anyhow, I'm hoping to have this figured out and fixed before the meeting on Saturday."

"The point of the whole exercise is to eventually hack the PACE FIG-Forth into an IMP-16 FIG-Forth. IMP-16 was National's earlier multi-chip 16-bit microprocessor, introduced in 1973. The PACE architecture was similar to the IMP-16, and the IMP-16 in turn was somewhat inspired by the Data General Nova. Last year I was given a homebrew IMP-16 computer system, but not too much software for it, so it seems like getting Forth running on it should be an easy way to make it somewhat useful."

13:50

Killer Catalogs - Kevin Appert
"I will talk about the big books of industrial stuff that Grainger, McMaster Carr, and Rutland publish."

Harbor Freight

14:23

Break

14:30

PropellerForth - Cliff L. Biffle
"I have a newly rewritten PropellerForth, based on the lessons I learned from the first three years. I'd be happy to share what I've got and what I've learned about this curious architecture."

PropellerForth

PropForth

SpinForth

14:47

Polaroid's Ultrasonic Sensors - Dave Jaffe
Dave will describe the operation of the Polaroid's ultrasonic sensors and how to interface to them in an embedded environment.

15:17

Upcoming Events of Interest - All Assembled
Maker Faire, Towel Day, trade shows.

15:25

15:24 --- Randomly Rambling Ramble Randomly - All Assembled
Who knows what we'll talk about?

Items from the SVFIG List:

MS-Debug removed from Windows

Mitch Bradley C-Forth for the ARM

The FIG/SVFIG website:

Cobwebs

Forth Day videos - has anyone seen the beta?

Who's Who? Who's missing in action?

15:15

16:00

Adjourn

Other items:

Computer

Turn off USB thumb drive autoplay

Other

Dynamic images (Albert Einstein's blackboard)

Mplayer - open source media player