MIPS-Emulator

A Java emulator written for a class a long time ago.

Execution Instructions

Built it and run run the command:

java GUIMain

A GUI will launch that displays current instruction memory, all 32 registers, and control buttons.

To load an assembly file, simply click load file. A file open dialog will appear. Select your assembly file and hit okay. The instructions will be parsed and their hex will appear in the pane.

Note: the PC counter always starts at 1000

Once loaded, to execute the assembly, click run. This will iteratively run each instruction through the machine, updating registers and reading / writing from system memory as necessary.

If, instead, you'd like to see a step-by-step execution of the assembly program, click step repeatedly. Each time you click step, the machine will run the assembly line at the PC counter. In this way, you can control the speed and watch register evolution over the course of the program.

If the program ever arrives at a line which is 0x00000000 in instruction memory, it will halt execution.

At any point in the machine's execution, you may elect to load a different file. Loading a new file will clear instruction memory and reset the PC counter. In this way, you can run multiple programs on the same data, as registers and system memory are preserved.

Sample Input Files

In classical fashion, sample input has been provided. In the root directory, there are five files:

• mipsin
• mipsin2
• mipsin3
• mipsin4
• mipsin5 Each of these four files contain small assembly programs that, overall, utilize each of the commands recommended for implementation. You may load these files.

Source Code Files

All source code is in the folder labeled src. You may explore it at your leisure - everything is named fairly intuitively, and the subfolders contain code according to their name (for example, the ALU code is in the circuit folder).

Working Instructions

Currently working instructions are:

and   or    slt
add   sub   addi
lw    sw
beq   j

Support for labels is also present.

Input File Instructions

Each instruction line that does not contain a label must be tabbed in. Each instruction line that does contain a label must not be tabbed in. Without this whitespace, the parser will fail because it uses the whitespace for label detection.

Example:

<tab><instruction>

or

<label>:<instruction>

Again, see the input files for more examples.