mareloraby / tomasulo-simulation

Tomasulo Algorithm Simulation for a floating-point MIPS-like instruction pipeline, using vanilla JS and HTML

Motivation

The aim of the project is to simulate the tomasulo algorithm for a floating-point MIPS-like instruction pipeline, demonstrating out-of-order execution in the same way it was presented in the lecture through a tabulated visualization.

Implementation

We use HTML and JS to create our simulator. We started with creating the tables with HTML to have our simulator’s frontend ready. Then we represented them in the backend using arrays like:-

• Memory Table (Memory, 64 locations): holds the available memory locations and their contents. The contents of the memory are generated randomly with the start of the simulation.
• Execution Time Table (executionTimes): holds the amount of time taken for each instruction operation to execute. and JSON arrays like:-
• Instruction Queue (InstructionQ): contains the instructions in their desired order of issuing, the cycle where they were issued, the start and end of execution cycles, and the write back cycle.
• Add and Sub Reservation Table (AddReserv): contains 3 elements representing 3 reservation stations present in the simulator. Each reservation station holds an instruction opcode, a busy bit, vj, vk, qj, qk, and the reservation station’s tag. The opcode can be “ADD” or “SUB”.
• Mul and Div Reservation Table (MulReserv): contains 2 elements representing 2 reservation stations present in the simulator. Each reservation station holds an instruction opcode, a busy bit, vj, vk, qj, qk, and the reservation station’s tag. The opcode can be “MUL” or “DIV”.
• LD Reservation Table (LDReserv): contains 3 elements representing 3 reservation stations present in the simulator. Each reservation station holds an address, a busy bit, and the reservation station’s tag.
• SD Reservation Table (SDReserv): contains 3 elements representing 3 reservation stations present in the simulator. Each reservation station holds an address, a busy bit, v, q, and the reservation station’s tag.
• Register File Table (Registers): contains 32 elements representing 32 registers (0-31) present in the simulator. Each register holds q, v, and the register name.

We then added input fields in the Execution Time HTML table (id=’ETs’) and the Instruction Queue HTML table (id=’IQ’) in order to allow users to enter each operator’s execution time, as well as entering the instructions they would like to run. Moreover, we added 2 buttons, “start” and “next” to control the clock cycle. Each button’s functionality is explained later.

How to run:

Open Tomasulo.html in the browser, enter the instructions and the execution times, then click “start” to start the simulation. Click “next” to increment cycles.

Memory and its content can be viewed in the browser's console.

Team members:

• Hadeer ElHussen
• Mariam Tamer
• Maryam ElOraby
• Rawan Reda
• Rowan Amgad