This repo contains fixed copies of the annotated BBC MOS 1.20 disassembly from http://mdfs.net/Docs/Comp/BBC/OS1-20/ as well as scripts and additional files that permit automated conversion into ca65 syntax.
Building requires two invocations of ./bin/convert.sh and
then one of ./bin/compile.sh.
The two passes of convert.sh are necessary to be able to convert
both forward and backwards code references into labels - the first
pass finds the addresses that are targets of references, and the
second writes those labels into the source.
Fixes to the original disassembly files include:
- convert all files to NL terminated
- split FC00 file at FF00 so I can use the real ROM contents in place of JIM/FRED/SHEILA
- ensured all hex constants are prefixed accordingly
- replaced a few addresses with computed offsets from labelled addresses
- removed some duplicate chunks of code left over from the file split
- inserted a couple of missing instructions
- fixed character case errors in some string constants
- resolved various other minor typos