This is a new implementation of RetroForth and a little virtual computer (named napia) to run it.


* dual stack architecture

* 64k cells of word addressed (32-bit) memory

* 41 instructions

* four instructions per word

* block storage device (1k cells per block)

* direct threaded retroforth image

* includes a block editor and sample blocks

* eight virtual processor cores

* per-core stacks and registers

* interrupts

* additional i/o devices

The source and documentation are distributed under the ISC license.


Get the snapshot, uncompress, and build the napia vm for your system.

napia specifications

napia Latest Snapshot

Source Repositories

Currently the full source tree can only be obtained via git:

git clone

The Other Systems

RetroForth implementations run on three virtual computers: ilo, napia, and nga. The napia system is bigger than ilo, but smaller than nga.