Overview

Tomasulo.py

This is a python module that implements Tomasulo's algorithm on a stream of instructions and prints when each instruction entered the issue (IS), execute (EX), write-back (WB), and commit (CM) stages. It also notates where instructions had to wait for data dependences or structural dependences/hazards.

Input is a list of tomasulo.Instruction which are to be run. Opcode is the opcode of the instruction and is used to decide which functional unit to send it to. Write register is the name of the register that this instruction will write to. Read registers is an iterable of the register names that this instruction reads. You can see an example invocation in test.py.

Current Limitations

  • Hardware is not configurable. Eventually it might be nice to be able to configure the functional units to have multiple units of a type or to change the mapping from opcode to functional unit. Or to be able to commit/issue/write-back multiple instructions in a cycle.
  • Limited input format. It would be nice to be able to use as input a file with the instructions in text.
  • Flexibility in running module. Right now you have to build a python file and import this module. It would be nice to be able to run tomasulo.py either directly from the command line or as a python module.
  • Configurable write-back stage. Currently all instructions use the WB stage. Store and branch instructions technically don't need to -- it might be nice to be able to make this simulator respect that.

If you have ideas, feel free to open an issue or submit patches or email me or whatever. I'd love to hear them. :-)