Java MMIX Interpreter

Disclaimer

This interpreter was written as an exercise to better understand the MMIX processor and its instruction set. Use at your own peril! ;-)

Currently the simulator is in a kind of "tracing bullet" state where it is able to load and execute very simple programs. I will continue working on it as time allows. The memory sub-system seems complete, the processor is a work in progress.

Although this is not exactly a Java port of Knuth's MMIX simulator, I liberally read his C code and based this work on it. Any good idea in this code is to be attributed to the original implementation, whereas all bugs and mistakes are solely mine.

References

• MMIX documentation: http://mmix.cs.hm.edu/doc/index.html
• MMIX opcodes: http://mmix.cs.hm.edu/doc/opcodes.html
• Knuth's MMIX simulator documentation: http://mmix.cs.hm.edu/doc/mmix-sim.pdf

Running

To run the simulator:

java -jar jmmix.jar <mmo file>

or you can simply execute the unit tests (mmixal needs to be in the PATH for the tests to run).

Running the simulator with logging:

java -Djava.util.logging.config.file=src/test/resources/logging.properties -jar jmmix.jar <mmo file>

Testing

To run the tests:

mvn test

The tests must be run under a system that has bash, mmixand mmixal in the PATH.

Useful commands

To inspect the content of MMO files:

hexdump -e '1/1 "%03_ad |"' -e '4/1 " %02X" " | "' -e '4/1 "%_p" "\n"' -v <mmo file>

Reading an MMO as a series of long to cut and past into LoaderTest:

hexdump -e '1/1 "0x"' -e '4/1 "%02X" "l,\n"' -v 

Know issues

• rL and the register stack are not implemented yet
• rA is not fully implemented yet