Start a program
Choose an example to load it and its registers automatically, or import a program and register file from the toolbar. Press Load program after editing source by hand.
Run and inspect
Use Step, Run 10, Run, Pause, Undo, and Reset to control execution. The current source line and program counter are highlighted as the machine runs.
Breakpoints and watches
Click an executable line number or the circle beside a memory row to toggle a breakpoint. Click a register name or memory address to add it to Watches.
Edit machine state
Right-click a register or memory row, or use its visible Edit button, to change it. Clicking a capability register follows its range in memory.
Save work
Your editor and preferences are saved locally.
Keyboard shortcuts
Space Step · R Run · Backspace Undo · X Reset · arrow keys move memory · Tab follow the program counter.