I'm interested in supporting Microchip's PIC16, PIC18 – and, possibly, PIC24 and dsPIC33 – chips in muforth.
One of the issues with rolling your own language – especially if, like muforth, it is a cross-compiler that targets microcontrollers – is that you need to find or create, for every chip you care about, "equates" files that describe the i/o registers, their memory addresses, and their bit definitions.
It's a lot of work – and error-prone – to type these in by hand. For the Freescale S08 and the Atmel AVR I was able to get pretty good results by "scraping" the PDF files by hand (yes, by hand, with a mouse), pasting the results into a file, and then running code that processed the text into a useful form.
For the STM32 ARM microcontrollers I wrote code that shoddily "parses" .h files (which I found in ST's "Std Periph Lib" and STM32Cube zip files – I tried both) and prints out muforth code.
I did something similar for Freescale's Kinetis microcontrollers, only instead of trying to parse .h files, I discovered Keil's CMSIS-SVD files, and Keil's CMSIS-Pack database, and wrote code to download pack files, and parse the constituent SVD files.
Microchip has done something similar: they have a pack repository site, where they host .atpack files, which are ZIP archives of chip support files needed for their toolchains. In particular, in each family pack, there is a directory of .ini files that describe the memory layout, i/o register addresses, and the bit fields making up each i/o register.
This is our goldmine.
To generate the examples shown in the CHIPS variable, just type make. This will download the necessary packs, unzip them, and convert the .ini files for the specified chips to .mu4 files in the mu/ directory.
If you want to create a custom list of CHIPS, you need to figure out which packs you need to download. To see a list of everything, do:
MATCH="." make show-packs
The MATCH variable is a Lua pattern, not a POSIX regular expression, but it shouldn't be hard to narrow down the list by changing the MATCH expression. . matches any character; + as a suffix does a greedy "zero or more" match of the preceding character; - does a non-greedy "zero or more" match. If you want to match a literal - you have to spell it %-.
Once you have a list that you like, change show-packs to get-packs. The packs will be downloaded and placed in the pack/ directory.
make unzip-packs
will unzip any .ini files found in the packs into a subdirectory of the ini/ directory, with the same name as the pack. Find the chips that you are interested in in one these subdirectories, and put their names – minus the .ini extension – in the Makefile as the value of the CHIPS variable.
If you later download more pack files, make unzip-packs will only unzip the new files. It will leave any existing files alone.
Also, if you want to make sure you have the latest list, make update will force a download of the pack index.
Once you have populated ini/ and set the CHIPS variable, do
make chips
and a .mu4 file will be generated in the mu/ directory for each chip that you specified.
See the LICENSE file for details. Do whatever you want! Have fun!