Open. Run. Understand.

See what your code makes the machine do.

A free MIPS learning environment in your browser. Write assembly, inspect registers and memory, step backwards and explore Mini-C — without installing Java.

Open webMARS Try the first lesson →

Free and open source · Local work without an account

webMARS interface showing the editor, registers and memory — The state of the machine, alongside your code.

One workspace, from source to execution

Assemble MIPS, run a program and inspect the state it changes. Use the same environment for your first instructions and multi-file projects.

Make the invisible visible

Explore the stack, memory, devices and a separate five-stage Pipeline Lab. Functional execution and pipeline timing are distinct models.

Ready to teach, easy to share

Share permanent example links and versioned publications. Students can edit, execute and download locally without creating an account.

Choose where to begin

Learn MIPS. One instruction at a time.Start the class with MIPS, not installation.Follow a function into the stack.Understand why a pipeline waits.From Mini-C to MIPS you can inspect.