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 2.12, released 2019-02-10: asm6809-2.12.tar.gz. Older versions.

Debian snapshot builds of this and other software are available for amd64 and i386 architectures. Add the following lines to your /etc/apt/sources.list, run apt-get update, then apt-get install asm6809.

deb testing main
deb-src testing main

Ubuntu snapshot builds of this and other software are available in this PPA on Launchpad.

Windows binaries built using MinGW: 64-bit Windows, 32-bit Windows

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 2.12

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 10 Feb 2019