Install xa with Homebrew, apk, apt, dnf, MacPorts, Nix, pacman, zypper

Project links

• Homepage
• Repository
• Upstream docs
• Package manager page

Commands and aliases

• file65
• ldo65
• printcbm
• reloc65
• uncpk
• xa

Project history

The original xa package is credited to Andre Fachat for 1989-1997. Later changes are credited to Fachat, Jolse Maginnis, David Weinehall, and Cameron Kaiser, with Kaiser listed as the official maintainer in current manual pages.

Fachat's public mirror describes xa65 as originally authored by him and currently maintained by Cameron Kaiser at Floodgap. The repository also notes that xa65 runs on Unix and Unix-alikes, produces 6502 and 65816 code, and comes with a set of tools.

Adoption history

xa survived because the 6502 ecosystem stayed alive: Commodore 64, Apple II, Atari 8-bit, NES-adjacent, 65C02, and 65816 programmers kept needing a dependable cross-assembler on contemporary Unix-like systems. The manual's own 'Over 30 Years of Xa' note captures its unusual longevity.

The tool is distributed by multiple Unix-like package systems and is referenced in retro-computing circles because it is simple enough for small projects but has features expected by serious 8-bit work: segments, labels, listings, conditional assembly, a C-like preprocessor, o65 relocatable output, and companion tools such as ldo65 and reloc65.

How it is used

Users write 6502-family assembly on a modern host, select options for CMOS 65C02 or 65816 opcodes, define include paths and macros, and emit either sequential binaries or o65 relocatable objects. The tool can also produce listings and label files for later inspection or disassembly.

xa is commonly used where exact addresses and binary layout matter: ROMs, monitor programs, demos, small operating systems, bootstraps, and retro-computing utilities. Its linking section documents both o65 object workflows through ldo65 and direct binary composition with explicit padding.

Why package nerds care

xa is one of those packages that signals a living retro toolchain rather than nostalgia alone. It is not a generic assembler; it is a long-maintained 6502 cross-assembler with enough compatibility switches and object tooling to fit real historical codebases.

Timeline

• 1989-1997: Original xa package by Andre Fachat.
• 2000s: Continued maintenance adds portability and package-system visibility.
• 2024: Current manual pages credit additional changes through 2024 and identify Cameron Kaiser as official maintainer.
• 2020s: xa remains packaged and used for 6502, R65C02, and 65816 cross-development.

Related projects

• cc65 is another prominent 6502 development suite, with ca65 as its assembler.
• o65, ldo65, file65, and reloc65 form xa's relocatable-object side ecosystem.
• dxa is a related disassembler referenced by the xa manual.

Sources

• https://6502.org/users/andre/misc/
• https://github.com/fachat/xa65
• https://github.com/fachat/xa65/blob/master/xa/README.1st
• https://www.mankier.com/1/xa