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Swapforth is a cross-platform ANS Forth

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Statistics on swapforth

Number of watchers on Github 136
Number of open issues 15
Average time to close an issue 10 days
Main language Forth
Average time to merge a PR 8 days
Open pull requests 5+
Closed pull requests 4+
Last commit almost 3 years ago
Repo Created over 5 years ago
Repo Last Updated over 2 years ago
Size 7.42 MB
Organization / Authorjamesbowman
Page Updated
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Build Status Issue Stats

Swapforth is a cross-platform 16- and 32-bit ANS Forth.

Currently supported hosts are:

  • J1a - minimal 16-bit FPGA CPU with 8K of memory Demo
  • J1b - 32-bit FPGA CPU with 32K of memory
  • FT900 - 32-bit 100 MHz CPU with 256K flash, 64K RAM

Simulated hosts include:

  • Python in 16-, 32- and 64-bit big- and little-endian
  • J1a and J1b under Verilator

Recent changes:


  • Both Python 2.x and 3.x are supported
  • The shell now runs on Windows, with and without pyreadline
  • The iCEstick port is now running at 48 MHz
swapforth open issues Ask a question     (View All Issues)
  • almost 4 years How do I interface this fifo
  • almost 4 years serial data corruption at 460800
  • almost 4 years simulator (verilator) does not compile
  • almost 4 years j1a8k doesn't use all available ram
  • almost 4 years Issues with files in common and j1a
  • almost 4 years How to add new peripheral to the code
  • almost 4 years Ramping up the clock rate
  • almost 4 years shell.py issues on ArchLinux
  • about 4 years j1a IO is broken (SEVERE)
  • over 4 years Feature Request discussion: Should we split J1 variants and builds into separate git branches?
  • over 4 years j4a : do..loop not thread-safe
  • over 4 years AVX instructions for x64
  • over 4 years How do you do multi-line input with the shell?
  • over 4 years PIO0/PIO2 (HDR1/HDR2) access on icestick?
  • almost 5 years Can't connect using Python or Picocom when building from scratch
swapforth open pull requests (View All Pulls)
  • Better tutorial for the j4a's multitasking
  • The verilator testbench extended with possibility to dump the memory with all defined words to the hex file.
  • Fix#45-afonly+icepll+69Mhz -- for testing.
  • Fix#45 afonly+icepll
  • Fix#45 afonly
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