Simple Instruction Simulator

Project Objective:

Simulation of assembly instructions on an x86 32bit architecture with easy to use user interface.

Functionalities:

• General-purpose register easy access in the main panel of the simulator
• Running x86 32bit assembly code
  • step by step
  • entire asm code at once
• Memory view: hexll and side by side view (It allows the user to easily read the memory contents)
• syntax highlighting for the ISA (PS: for more instruction highlighting just edit the ISA.txt file with the instructions you want to be highlighted)

Core Modules:

• Unicorn
• Keystone
• Tkinter

Installation:

Be sure you have Python installed, then run the following commands to install the core modules used in this project:

   pip install unicorn   - for UNICORN engine 
   pip install keystone  - for KEYSTONE engine
   pip install tk        - for GUI engine

You may need to install additional modules needed by the core modules mentioned above.
If you want to have the same setup I used to test the application on another device you can run the following command in the terminal:

pip install -r requirements.txt  

For problems when installing any of the modules required by Keystone, use the following resource for the compiled version of the module.

The SIMULATOR

The main pannel

Step Simulation Example

Hexll Memory Format

Implementation details

Millstones

• Setting up the unicorn-keystone-Tkinter environment
  • Problems:
    • Combining keystone and unicorn for easy assembling and testing of asm code
• Adding memory viewing interface
  • Problems:
    • formating the memory in such a way that the user could read the data was a challenge at first
    • aligning memory cells
    • adding hexll format to the memory while keeping the structure mostly the same
• Step by step running mode
  • Problems:
    • Memory:
      • This was by far the most challenging part of the project, after I added this functionality I had problems with the regular running mode while displaying the memory because it tried to update at each memory access and it.
      • To solve this problem I choose to update the memory only while doing step by step simulation and just add a button for memory updates that the user can click and instantly update the memory.
    • Step by step Highlight:
      • It was hard at first to think of a way to map each line of code to a memory address as keystone doesn't provide a memory address instruction mapping
      • To create this mapping I had to assemble each line of code on its own and create the memory mapping in this way. After I had the memory - instruction map it was easy to map the program lines to the memory and after that highlight the lines

Similar projects:

1. Carlosrafaelgn’s simulator - allows the simulation of x86 assembly instructions, easy registers, and flags values access. The code runs without letting the user do a step by step simulation.
2. Davis simulator - allows the simulation of an entire assembly program along with a nice registers values viewing interface, flags, RAM, and the possibility to view memory by blocks of 1, 2, or even 4 bytes.
3. Schweigi’s simulator - an 8-bit simulator, with a reduced number of general-purpose registers, but it offers the user the possibility to run instructions step-by-step along with step highlighting.
4. Marss simulator

For bug reports please feel free to email me at: necula.leonard.gabriel@gmail.com