When you have existing assembly sources that compiled with old assembler, you can migrate them without re-writting everything by using the --mri option of GNU as.
This option enables a kind of compatibility mode with Motorola Assembly Language Specification. There are however a few restrictions:
- The ORG command is not supported. You must replace them with a definition of a section (section name).
- Single quote strings are not supported (CVS Binutils only).