# foci

`foci` is a small Forth implementation that prioritizes performance and portability. This threaded Forth implementation uses CPU registers and native execution to maximize efficiency.

Register usage is the only platform-specific requirement; otherwise, `foci` is written in 100% portable C. There is active support for x86\_64, ARM Cortex-M, and MSP430 architectures.

`foci` compiles to a binary object that can easily be linked into another application. Code size is less than 5 kB, while RAM usage is in the hundreds of bytes (primarily influenced by the configured stack and dictionary sizes).

## Available words

Many words from [core ANS Forth](https://forth-standard.org/standard/core) are supported. See `compat.txt` for a list.

Some features are not expected to be implemented:
* Pictured numeric output, e.g. `<# # #>`
* Double-width arithmetic

## Build instructions

Run `make` with a supported architecture target:

* `make x86-64`: x86\_64 processors (i386 is *not* supported)
* `make arm-cm4`: ARM Cortex-M4 microcontrollers
* `make msp430`: TI MSP430 microcontrollers