I've been following Ben Eater's series of videos about designing a small computer from discrete logic gates, I'm curious if there is a similar tutorial/book/reference for building a stack computer. I was thinking in the vein of Charles Moore's Sh-Boom processor or one of the individual computers in his green array chips. If not are there any references about building a stack computer that would be useful for a hobbyist at home?

EDIT: If there is specific knowledge about circuit diagrams, implementations or information relating to the NOVIX NC4016C, the soviet copies the Dauphin-1610/20, or the previously mentioned Sh-Boom processor I would be very interested. To my knowledge this covers the major stack processors developed during the 80's.

  • It feels like this question would be more appropriate on some electronics (like EE.SE) or maker site (like Hackaday). – Raffzahn Aug 6 '19 at 16:08
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    @Raffzahn: I think the question of which site is more appropriate would depend upon whether the person would be more interested in articles from the 1970s or from 2019. For 2019, web searching is probably better. For 1970s, asking humans may be better, given the number of articles which are available as scans but are not searchable. – supercat Aug 6 '19 at 16:18
  • Happy to post it to EE.SE, I'd checked both before posting here, and this one seemed to have a long and informative discussion about Forth. The only real reference in print I've been able to find is Phil Koopman's Stack Computers which was published in the late 80's. I'd hoped that the retro-computing aspect would perhaps open a few more doors as a result. – Fuzzy_Bunnys Aug 6 '19 at 16:20
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    thanks for the comments Raffzahn, I've edited the question to pertain specifically to some processors that were developed in the 1980';s. – Fuzzy_Bunnys Aug 6 '19 at 16:37
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    @Fuzzy_Bunnys It'd be on-topic if you made it more history oriented, but your original question doesn't belong on this site, really. We're not (predominately) experts in this topic. – wizzwizz4 Aug 6 '19 at 17:09

I've collected a number of resources in this answer that I've managed to find with additional searching on the internet. Additionally my copy of Stack Computers arrived in the mail and has been very useful. I've split links into professional/academic vs hobbyist.


Phil Koopman's Stack Computers dedicates its fourth chapter to hardware implementations of different stack computers. In particular it includes the NOVIX NC4016

Ultratechnology has a very good listing of forth chips, unfortunately listings to the Sh-Boom manual and associated information are broken and I have been unable to find them via google. Using the wayback machine gets you to the following page but unfortunately none of the actual documentation appears to have been archived.

I am unaware of any online resources regarding the soviet Dauphin chips.


Andrew Holmes has built two forth computers using TTL logic chips.

Thanks to user RETRAC for pointing out Mippy, another homebrew forth CPU. Unfortunately at this point there are no schematics online.

Rob Chapman built an 8 bit stack processor as a graduate student at the University of Alberta. He later on did work for Green Arrays and is listed on their website. A number of his papers were archived by the wayback machine. They include a project report and a design document for a stack based computer.


Additional information to complement the answer by Fuzzy_Bunnys:

1) An Forth chip I like very much is the J1. It even comes with the Verilog source.

It runs e.g. on an Xilinx Spartan 3E FPGA at 80 MHz, and is used for a real-word application (a Ethernet camera). It has a high code density, but a very simple "unencoded" instruction format (even simpler than the Novix NC4000 format).

Though it targets an FPGA, you could probably implement it with discrete chips with a bit of fiddling. But even for a Hobbyists, today's FPGA chips are not that hard to use.

It makes very clever use of the dual-port RAM on the chip; and the (custom) data and return stack is also dual-port.

2) You were asking about the Sh-Boom.

The company Patriot, which acquired the patent for the Sh-Boom, rebranded and reworked the Sh-Boom as the PSC1000 and targeted it to the Java market.

While I don't know any resource for the Sh-Boom itself, there is documentation for the PSC 1000 to at least get a good idea about the structure (even though the documenation only mentions Java, and not Forth, and it's not clear how much has changed from the Sh-Boom).

But you can clearly see the original 16 general purpose registers of the Sh-Boom, an additional Local-Register stack that might have been the return stack on the Sh-Boom, the Operand stack which would have been the data stack, and the overall instruction format which probably hasn't changed much (though details of the instructions might have).

Though it doesn't look simple enough I'd use it to base any hobbyist project on, the J1 architecture looks much better suited to that.

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