Visual RISC Simulator (8085-Based)

A visual RISC (Reduced Instruction Set Computing) simulator with a graphical user interface (GUI) built using Python and Tkinter.

This simulator models a simple RISC CPU but uses the register set (A, B, C, D, E, H, L, SP, PC) and instruction mnemonics of the Intel 8085 as its architectural base. It allows you to write, assemble, and execute assembly code while visualizing the CPU's internal state, memory, and clock cycle execution.

Features

• Interactive GUI using Tkinter in a three-column layout.
• 8085-Based Register Set: Real-time visualization of A, B, C, D, E, H, L, SP, PC, FLAGS, and IR.
• 1KB (1024-byte) Memory:
  • Color-Coded Memory Map to visually distinguish Code (yellow), Data (green), and Stack (blue) sections.
  • Memory Navigation controls (Go to, Next, Prev) to instantly inspect any part of memory.
• Assembly Code Editor with instruction highlighting during execution.
• CPU Control:
  • Assemble: Load the program into memory.
  • Run All: Execute the program at full speed (with a slight delay for visualization).
  • Step: Execute one instruction at a time.
  • Reset: Clears all registers, memory, and state.
• Clock Cycle Counter to track the simulated execution time of your code.
• Stack Boundary Detection with "Stack Overflow" and "Stack Underflow" error reporting.
• Visual CPU State display (FETCH, DECODE, EXECUTE, HALTED).

Visual Layout

The simulator is organized into three columns for a clean workspace:

• Column 1: Displays all 8085 registers and the running Clock Cycle count.
• Column 2: Contains the Assembly Code Input, control buttons (Assemble, Run All, Step, Reset), the Output console, and the current CPU Stage.
• Column 3: Shows the full 1KB memory, the color-coded legend, and navigation controls.

Usage

1. Run the simulator:

   python your_simulator_filename.py

2. Enter your 8085-like assembly code in the "Assembly Code Input" box.
3. Click Assemble to load your program into memory.
4. Use Run All to execute the full program or Step for single-step execution.
5. Click Reset to return the simulator to its initial state.

Supported Instructions (8085-like)

This simulator supports a reduced instruction set that uses 8085 mnemonics.

Data Transfer

• MVI R, val (e.g., MVI A, 50): Move an immediate 8-bit value into a register.
• STA addr (e.g., STA 300): Store the Accumulator's (A) value at a memory address.
• LDA addr (e.g., LDA 300): Load the Accumulator (A) with the value from a memory address.

Arithmetic

• ADD R (e.g., ADD B): Add register R to the Accumulator (A = A + R).
• SUB R (e.g., SUB C): Subtract register R from the Accumulator (A = A - R).

Stack & I/O

• PUSH R (e.g., PUSH B): Push a register's value onto the stack.
• POP R (e.g., POP D): Pop a value from the stack into a register.
• INP R (e.g., INP A): (Simulated) Show a popup to get an input value for a register.
• OUT R (e.g., OUT B): (Simulated) Print a register's value to the Output box.

Control

• HLT: Halt program execution.