André Fachat’s fast and portable two-pass 6502/65816 crossassembler #Software #VintageComputing

Cameron Kaiser, maintainer of André Fachat’s fast and portable two-pass 6502/65816 crossassembler, has released the latest version: xa (xa65) 2.4.0.

It runs on Un*xy things and Windows (with Cygwin or msys2 or similar), and probably other operating systems as well. xa 2.3 has had a good run, but it’s served 17 years as the minor release (no joke: 2.3.0 came out in 2006) and time marches on. There are new features to add and old cruft to sweep away. But it’s still compatible with all the systems 2.3 was compatible with and adds several new features, including:

  • Listing mode, allowing side-by-side byte output with the lines in your source. You can even emit it in HTML.
  • ca65 compatibility mode that allows many of the same pseudo-ops and “cheap local labels” support. Although this obviously doesn’t accept every feature in ca65, it can ease translating your assembly source considerably — because once you switch to xa, you won’t want to go back. 🙂 This feature is also used for other compatibility options such as MASM and allowing some C-like expressions.
  • Assertions at the preprocessor level (#error) and assembly level (.assert), allowing controlled errors when static assertions are violated.
  • Linker enhancements for .o65, including deferred linking of undefined symbols.
  • You can now get the assembler major and minor version in the preprocessor with XA_MAJOR and XA_MINOR. Other predefined macros may appear in future versions.

You can read more here. You can download it and read documentation in man(1) format (converted to HTML) from the main xa65 home page.


Adafruit publishes a wide range of writing and video content, including interviews and reporting on the maker market and the wider technology world. Our standards page is intended as a guide to best practices that Adafruit uses, as well as an outline of the ethical standards Adafruit aspires to. While Adafruit is not an independent journalistic institution, Adafruit strives to be a fair, informative, and positive voice within the community – check it out here: adafruit.com/editorialstandards

Happy New Year 2025
Happy New Year from Adafruit!

Stop breadboarding and soldering – start making immediately! Adafruit’s Circuit Playground is jam-packed with LEDs, sensors, buttons, alligator clip pads and more. Build projects with Circuit Playground in a few minutes with the drag-and-drop MakeCode programming site, learn computer science using the CS Discoveries class on code.org, jump into CircuitPython to learn Python and hardware together, TinyGO, or even use the Arduino IDE. Circuit Playground Express is the newest and best Circuit Playground board, with support for CircuitPython, MakeCode, and Arduino. It has a powerful processor, 10 NeoPixels, mini speaker, InfraRed receive and transmit, two buttons, a switch, 14 alligator clip pads, and lots of sensors: capacitive touch, IR proximity, temperature, light, motion and sound. A whole wide world of electronics and coding is waiting for you, and it fits in the palm of your hand.

Have an amazing project to share? The Electronics Show and Tell is every Wednesday at 7:30pm ET! To join, head over to YouTube and check out the show’s live chat and our Discord!

Join us every Wednesday night at 8pm ET for Ask an Engineer!

Join over 38,000+ makers on Adafruit’s Discord channels and be part of the community! http://adafru.it/discord

CircuitPython – The easiest way to program microcontrollers – CircuitPython.org


New Products – Adafruit Industries – Makers, hackers, artists, designers and engineers! — New Products 11/15/2024 Featuring Adafruit bq25185 USB / DC / Solar Charger with 3.3V Buck Board! (Video)

Python for Microcontrollers – Adafruit Daily — Python on Microcontrollers Newsletter: CircuitPython 2025 Wraps, Focus on Using Python, Open Source and More! #CircuitPython #Python #micropython @ThePSF @Raspberry_Pi

EYE on NPI – Adafruit Daily — EYE on NPI Maxim’s Himalaya uSLIC Step-Down Power Module #EyeOnNPI @maximintegrated @digikey

Adafruit IoT Monthly — The 2024 Recap Issue!

Maker Business – Adafruit Daily — Apple to build another chip at TSMC Arizona

Electronics – Adafruit Daily — Lower power!

Get the only spam-free daily newsletter about wearables, running a "maker business", electronic tips and more! Subscribe at AdafruitDaily.com !


No Comments

No comments yet.

Sorry, the comment form is closed at this time.