Implement your design in the Java programming language. Your main program file must be called MIPSim.java.

Your simulator should implement the MIPS instruction set with the restrictions mentioned in the introduction. The test cases provided to you will exercise instructions of different formats, but not all instructions of each class. It would be wise to start by implementing just those instructions needed for the simple test cases, building up to a more complete set of instructions later. New examples may be provided nearer the submission deadline.

You may find it beneficial to split the work so that one partner concentrates on disassembly and monitoring output while the other partner concentrates on implementation of instructions. It would be wise to define interfaces for appropriate classes so that development can take place independently.

Your simulator should respond to commands on the standard input as follows. Only the first two characters are significant so commands could be shortened or even misspelt after the first two characters:

load "filename"

Reads in a MIPS program in file filename. Note: the filename must be enclosed in quotation marks. Each line of the file contains a 32-bit computer word expressed as eight hexadecimal characters. White space and text after the character ";" to end of line should be ignored. Blank lines should be ignored.

Any previously loaded program should be cleared. All registers are set to 0. The program counter is set to instruction 0. The memory of the simulated processor should be loaded with successive words starting at location 0.

dump

Prints a disassembled version of the program after a load command.

run [n]

Executes MIPS instructions using the current program counter until an exit syscall instruction is encountered, or, if a count is provided, n instructions have been executed. If no count is provided, the simulator should execute no more than 10,000 instructions before suspending the simulation in order to avoid loops.

step [n]

Executes a single MIPS instruction using the current program counter, or up to n instructions if a count is given. Prints a disassembled version of each instruction executed and displays the contents of non-zero registers once all instructions have been executed.