asm6809 is a portable cross assembler targeting the Motorola 6809 and Hitachi 6309.

Features arbitrarily complex expressions (with most C-style operators available), forward references, macro expansion and conditional assembly. Output formats are: Raw binary, DragonDOS binary, CoCo RS-DOS (or "DECB") binary, Motorola SREC, Intel HEX.


Source code version 2.13, released 2023-06-30: asm6809-2.13.tar.gz. Older versions.

Debian snapshot builds are available in the Apt repository.

Ubuntu snapshot builds are available in this PPA on Launchpad.

Windows binaries: 64-bit Windows, 32-bit Windows (cross-built using MinGW)

Git repository: git clone

The manual is available in these formats: PDF, HTML and plain text.

XRoar is a Dragon/Tandy CoCo emulator that can run the output from asm6809.

Notes for version 2.13

For full version information, see the ChangeLog.


License: GNU GPL version 3 or later <>.
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.

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Updated 30 Jun 2023