Over the years there have been a few CPUs designed to directly run a high-level programming language, the most common approach being to build a physical manifestation of a portable code virtual machine. An example might be the experimental Java processors which implemented the JVM. Similarly, in 1976 Itty Bitty Computers released an implementation of Tiny BASIC which used a simple virtual machine, and to celebrate 50 years of Tiny BASIC, [Zoltan Pekic] designed a CPU that mirrors that VM.

The CPU was created within a Digilent Anvyl board, and the VHDL file is freely available. The microcode mapping ROM was generated by a microcode compiler, also written by [Zoltan]. The original design could execute all of the 40 instructions included in the reference implementation of Tiny BASIC; later iterations extended it a bit more. To benchmark its performance, [Zoltan] set the clock rate on the development board equal to those of various other retrocomputers, then compared the times each took to calculate the prime numbers under 1000 using the same Tiny BASIC program. The BASIC CPU outperformed all of them except for Digital Microsystems’ HEX29. Continue reading “Designing A CPU For Native BASIC” →