vasm is a portable and retargetable assembler to create linkable objects in various formats or absolute code. Multiple CPU-, syntax and output-modules can be selected.
Project homepage: http://sun.hasenbraten.de/vasm/
Assuming the current folder contain assembly sources:
docker run --rm -v $PWD:/data -w /data nguillaumin/vasm vasmm68k_mot -Ftos -devpac source.s
Make is also installed on the image:
docker run --rm -v $PWD:/data -w /data nguillaumin/vasm make