Modifying the JAS Assembler

Program Operation
...     Using Mic1MMV
... ...         Modifying the JAS Assembler

You may also wish to extend or modify the functionality of the IJVM assembler. Adding or modifying instructions which are similar in format to the existing IJVM instructions is actually quite simple: you simply modify ijvm.conf. (Of course, you will need to implement any new instructions in the microprogram).

  1. A copy of the default ijvm.conf is contained in the lib directory of the distribution. Edit this file, adding or modifying the opcode (column 1) and mnemonic (column 8). The meaning of argument descriptors such as varnum, label, index, etc. is given in Tanenbaum, Structured Computer Organization, 5th Edition. You should also include a comment describing the new operation(s).
  2. Run the simulator from the same directory as the modified ijvm.conf. You may rename the file as long as you reference the new name in Preferences.

    Note: If your configuration file cannot be found, Mic-1 MMV will use the default configuration corresponding to the IJVM language.

Test the modified assembler by loading and assembling a JAS program containing the new operators using File | Assemble / Load JAS file. Remember that once you have an assembled program you can load it directly using File | Load IJVM program). Your IJVM program should make use of the new operators.