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First Launch

When you start QtRvSim, or when you select File > New Simulation, the Pre-sets and ELF File dialog will appear. This dialog allows you to select a hardware configuration (pre-set) and, optionally, load a program to run.

QtRvSim launch window

Dialog Options

  • Config Pages (Left Pane) Displays the different categories of hardware settings (ISA, caches, etc.). For now, focus on the Pre-sets and ELF File page. The other pages will be covered in later chapters.

  • Pre-set (Radio Buttons) Choose a predefined hardware configuration:

    • No pipeline, no cache: Simplest single-cycle processor model without cache memory. Ideal for learning basic instruction behavior.
    • No pipeline, with cache: Single-cycle processor with cache enabled.
    • Pipelined, no hazard unit, no cache: Classic 5-stage pipeline without automatic hazard handling. Useful to demonstrate data/control hazards. No cache.
    • Pipelined, hazard unit, with cache: More realistic 5-stage pipeline with hazard detection/forwarding enabled, plus caches.
    • Custom: Advanced mode – configure settings manually through the other Config pages.

  • Reset at compile time (reload after make) If enabled, the simulator automatically reapplies the selected configuration each time you assemble a program. Recommended: Keep this option checked.

  • ELF Executable Use the Browse button to load a precompiled RISC-V ELF program (.elf). Tip: For most workflows, you’ll write and assemble assembly (.s) code directly in the editor instead.

  • Action Buttons

    • Example: Loads a default example assembly program into the editor with the selected pre-set. This is the easiest way to get started.
    • Start empty: Opens the simulator with the selected pre-set and an empty editor, ready for you to write or load code.
    • Load machine: Applies the selected pre-set and loads the chosen ELF executable.
    • Cancel: Closes the dialog without applying changes.

For your first run, we recommend selecting either:

  • No pipeline, no cache (simplest model), or
  • Pipelined with hazard unit and cache (closer to a realistic processor).

Then click Example (to load a sample program) or Start empty (to write your own).

For this manual, we’ll begin with Start empty and the No pipeline, no cache configuration.