Alternative tools for the GA144 multi-computer chip using Python3.

These tools are provided as a CLI script and a Python3 library. They support two forms of assembly, bootstream generation and loading.

1. Installation
2. First program
3. Usage
   1. Use with Greenarrays evalboard
4. Assembly syntax
   1. Aforth syntax
   2. ASM syntax
5. Boot streams
6. Documentation
7. Example code
8. GA144 Simulation

Installation

To install from pypi, run: pip3 install ga-tools

To install from source, first clone the repository and then run: python setup.py install

This will install the ga cli script and the ga_tools Python3 library.

First program

To check that everything works, first connect the GA144 eval board or chip. On GNU/Linux run dmesg to find the serial port it is connected on. Try running the fibonacci.ga example:

  ga examples/fibonacci.ga --port /dev/ttyUSB0

Replace /dev/ttyUSB0 with the correct serial port. This should print out the first 15 numbers of the fibonacci series before exiting.

Usage

ga -h prints a summary of the cli options.

Print assembly

ga FILE.ga --print prints a summary of the assembled program for each node alongside its disassembly.

Add the --node N option to print a single node.

Program loading

ga FILE.ga --port NAME streams the program into serial port NAME.

Use --bootstream TYPE to specify the boot stream type, default is '708'. See Boot streams for more on the different boot stream types.

--baud sets the serial baud rate. Default is 460800. The rate can range from 9600bps to 1Mbps.

By default ga will listen for data being sent back from the ga144, use option --no-listen to disable that.

Show program size

ga FILE --size prints the RAM usage of each node.

JSON output

ga FILE.ga --json prints the assembled program as JSON. The bootstream is included with the --bootstream TYPE option.

Use the --outfile NAME option to direct the JSON output to a file.

Use with Greenarrays evalboard

To load code into the target chip via port A, or into the host chip via port C, use the 'async' boot stream: ga FILE.ga --port /dev/ttyUSB0 --bootstream async

To load code into the target chip via port A, use the 'target' boot stream: ga FILE.ga --port /dev/ttyUSB0 --bootstream target

Disabling optimization

The --disable-0-opt option prevents compiling '0' as 'dup dup or'. The --disable-plus-opt options prevents automatic insertions of no-ops before the + or +* instructions.

Assembly syntax

These tools provide support for two forms of assembly. The default form is called aforth and is similar to arrayforth supported by the tools and documentation provided by Greenarrays.

The second form is called ASM and is closer to a traditional assembly language, with one line of source for every machine word. This form is used when full transparency is needed and can be useful for writing some kinds of optimizations.

Both forms support the same basic instruction set. Read about it here or in the F18a Product Brief.

Both forms are case insensitive.

Aforth syntax

Aforth provides convient layer above raw assembly, bringing its syntax closer to that of the Forth. It allows reuse of existing code for the ga144 and helps with the use and comprehension of the valuable documentation from Greenarrays. Additionally aforth syntax is easier for compilers to generate.

Aforth is intended to remain compatible with the output of the chlorophyll compiler.

TODO

ASM syntax

To use asm syntax instead of aforth, use the ASM directive after specifying the node coordinate, for example:

node 508 ASM
(...)

Each node that uses the asm syntax must be marked with asm.

node, chip, and other directives must start on a new line.

TODO

Boot streams

A Boot stream is an instruction stream used to load programs into the ga144. You can read about the boot protocols here

You need to pick the correct boot stream type depending what node you are loading the code into, and the chip topology when using multiple chips.

The boot streams names for the --bootstream option are named after the node they are loaded into. The following types are supported:

• 708 (alias async) Asynchronous serial boot.
• 708-300 (alias target) For loading code into node 300 via another ga144 which is loaded from node 708. Use this for the target chip on the Greenarrays evalboard.
• 300 2-wire synchronous boot. Used by the 708-300 stream

The boot stream type defaults to 708 with one chip and 708-300 with two chips.

If stream 708-300 is used to load code into both chips, they must be named "host" and "target". The "target" chip gets its bootstream loaded through the "host" chip.

Documentation

Greenarrays documentation is the valuable resource.

For a quick intro read the GA144 Product Brief and the F18a Product Brief

For more serious programming the F18A Technology reference and GA144 Chip Reference are very useful.

colorforth.com contained many pages useful for programming the ga144. The site is down so links here are for a mirrored copy, a list of useful links has been collected here.

• Instructions

• Arithmetic routines

GA144 Simulation

These tools do not currently provide a simulator, but they do provide support for this emacs-based simulator: github.com/mschuldt/ga144-sim

After installation of that simulator, it can be run with: ga FILENAME --sim

If the --bootstream option is provided it will simulate the loading of the entire boot stream.This is disabled by default as it's not usually interesting and is very slow. The boot stream is only supported through node 708 in simulation.

Example code

The examples/ directory provides numerous example programs for the GA144.

See examples/README.md for a summary of each one.

Comparison to arrayforth

This version of aforth differs from arrayforth supported by Greenarrays in several ways. Knowing the differences is helpful if you already know arrayforth or if you want to use the Greenarrays documentation.

• No semantic color
  • standard forth syntax for words and comments
  • hex,bin literals: 0xN, 0bN
  • boot descriptors and other yellow words are reserved keywords.
• north, east, south, and west get resolved to correct ports: up, down, left, or right
• Each node has a seporate namespace
  • word@coord compiles a call to =word= in node =coord=.
  • The word reclaim has no use.
• Automatic nop insertion.
  • Can be disabled.
  • Currently inserts nops even when not actually needed
• Arguments follow the yellow words. For example, use 'node 715' instead of 715 node'.
• Generalized host computations during compilation are not supported. The compiler is not a forth interpreter.
• There are no grey words
• Automatically shift words when destination address does not fit in word. arrayforth does not compile in such situations, manual word alignment is necessary
• words may be called before their definition
• aforth does not support multiple labels at the same location

Other GA144 tools

• ga144tools https://github.com/jamesbowman/ga144tools

  • Assembler similar to the ASM supported here.
  • Interesting examples including code for virtual machines and VGA.
  • Includes a flash based virtual machine and compiler for it.

• Chlorophyll https://github.com/mangpo/chlorophyll

  • A high level c-like language with automatic partitioning for the ga144

• Arrayforth from Greenarrays

Todo

• Test Windows/mac support
• Proper guide to using aforth
• Fix line/col numbers in error messages
• GA144 Simulator