If you bought a Casio, Sharp or Tandy handheld in the mid to late 80s and it advertised assembly language capabilities, you might have been pleased to find you can write programs which run faster than the in-built Basic. And yet, it turns out the assembly language is running not on the microprocessor in your handheld, but on a VM, designed for educational purposes back in the 60s and used as the fictitious target machine in examinations in the 70s.
That’s what CAP-X means on the bezel here:
Here’s the full story - a long read but very worthwhile! (Peppered with value judgements from the headline onwards - let’s not follow that lead here.)
We’re told the Basics offer PEEK POKE and CALL… but that doesn’t relate to the assembly language target!
Although the Sharp-derived Radio Shack TRS-80 PC-2 (PC-1500) had documented PEEK, POKE and CALL commands in BASIC to run machine language programs on its 8-bit Sharp LH5801 CPU, the only pocket computers Radio Shack advertised as having an assembly language feature were the PC-5 and PC-6
Probably the first actual computer that could run CAP-X code — in a simulator, mind you — was one of the OKITAC-4300 line, which stood for Oki Transistor Automatic Computer.
Later in the article
With the specification now public in major Japanese computer magazines like I/O, there were certainly other software implementations for the home and personal computers of the time such as this one for UCSD Pascal, but the architecture became a potential selling point for other small systems — really small ones. Indeed, probably CAP-X’s most famous commercial implementations were in pocket computers.
