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Al Williams

Dr. Dobb's Bloggers

Update: One Instruction Wonder

March 31, 2010

You might remember the "One Instruction Wonder" -- my FPGA-based CPU that has only one instruction. Follow on articles revealed my adaptable cross assembler for it and my Forth compiler. There's also some updates on the One-Der website.

As I mentioned in the article, I was disappointed that I wasn't the first to invent this architecture. And as you'd expect, I got a lot of e-mail from other people who have interest in these computers.

One correspondent mentioned that Able was a one instruction CPU used in an early music synthesizer and he's implemented it on an FPGA.

I also heard from the Tampere University of Technology in Finland. They've developed an impressive suite of tools relative to this architecture, although the tools currently don't support Verilog.

Another interesting series of e-mail were with Wizdom Research. I don't think they've "pressed" any silicon but they've obviously given this architecture a lot of thought and there's a huge web site outlining their plans for the WIZ processor.

Of course, the original article was Slashdotted and there were a TON of comments in that forum. Of course, many of those were characteristically snarky (which is what makes Slashdot fun) but there were some thoughtful serious comments as well. Of course, even among the serious comments many people seemed to want to compare it to, for example, a Pentium or an Athlon which really wasn't the likely target for such a CPU. In fact, on the Wizdom Research site I noticed a particularly salient Charles Babbage quote:

"Propose to an Englishman any principle, or any instrument, however admirable, and you will observe that the whole effort of the English mind is directed to find a difficulty, a defect, or an impossibility in it. If you speak to him of a machine for peeling a potato, he will pronounce it impossible; if you peel a potato with it before his eyes, he will declare it useless, because it will not slice a pineapple." -- Charles Babbage, 1852.

I've been working on One-der for years. I tend to really move on it for awhile (often over the end of year holiday) and then shelve it for awhile and then pick it back up later. At the moment it is kind of on the shelf. But I'm not done. I still have plans to further increase its usefulness. Meanwhile, there's a surprising amount of work going on elsewhere on similar CPUs.

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