Main characteristics

• fixed size 8-bit instructions
• easy to implement two register machine
• top-of-stack relative stack access instructions
• variable precision literals via concatenation
• flexible word size, minor language changes required
• separate address spaces for stacks (word) and code/data (byte)

---

Note: for the initial prototype using frame pointer stack addressing and top-of-stack ops, check out archive/mk1 branch.

Goal

Have a simple to implement instruction set, in both hardware and software (e.g. JIT), and a below-C language for it with Forth-like metaprogramming.
On the language side this was mostly achieved, with the resulting language supporting basic control structures (conditionals, while loop, goto), named locals, expressions and quoting. On the machine side, a Verilog implementation is still pending, but a word-level JIT for x64 was prototyped (coming soon).

For a WASM-compiled web playground of the language, check out the latest demo.

Source structure

• fth contains the saladforth - currently C - implementation
• core contains a basic ISA emulator
• include contains common headers, including the opcode listing
• wasm contains the web demo

Inspiration

• ZPU
• UXN