Running Your First Program in Ripes

Experiment: Observing instruction execution in Ripes

Objectives

• Learn basic Ripes usage.
• Observe how registers change during instruction execution.
• Build an intuitive link between instructions and hardware behavior.

Principles

This experiment is based on the RISC-V ISA and uses a visual processor model to observe instruction execution.

Environment

• Simulator: Ripes
• CPU model: Single-Cycle Processor

Task: Step through an example program and observe registers

The following simple RISC-V assembly program adds two numbers:

addi x1, x0, 5   # x1 = 5
addi x2, x0, 7   # x2 = 7
add  x3, x1, x2  # x3 = x1 + x2

Steps:

1. Open Ripes and select Single-Cycle Processor as the CPU model.
2. Create a new program (or clear the editor) and paste the code above into the code editor.
3. Use single-step execution and observe how registers x1, x2, and x3 change.

Results

• A screenshot of the running program (including the registers window).
• Briefly explain how each instruction affects the register state.
• Verify whether the final result matches the program logic.

Question

• If you switch the CPU model to a multi-cycle or pipelined model, how does the timing of register updates change?