P-Code VM

P-Code VM is an educational virtual machine and debugger plugin for IntelliJ IDEA. It helps students explore compiler-generated intermediate code, stack-based execution, method calls, and recursion.

Install P-Code VM from the JetBrains Marketplace

Features

• P-Code syntax highlighting for .pcode files
• Execute P-Code programs from the editor
• Step through execution one instruction at a time
• Inspect the operand stack, symbol table, call stack, and runtime frames
• Explore method calls, recursion, and return values

Preview

Getting Started

1. Install P-Code VM from the JetBrains Marketplace in IntelliJ IDEA.
2. Create or open a file with the .pcode extension.
3. Add a P-Code program, such as the example below.
4. Right-click in the editor and select Execute P-Code to run the program, or Step P-Code to advance instruction by instruction.
5. Use the P-Code Console tool window to inspect execution and runtime state.

The editor actions also have default shortcuts: F5 for execution and F10 for stepping. Shortcut availability may depend on your IDE keymap.

Example: Recursive Factorial

This P-Code program computes the factorial of 5:

factorial-int,method,global,1
n,int,factorial-int,0
#P,label,global,15
#E1,label,global,8
@
STO n,0
LOD n,0
LIT 1,0
OPR 15,0
JMC #E1,false
LIT 1,0
OPR 1,0
LOD n,0
LOD n,0
LIT 1,0
OPR 3,0
CAL factorial-int,0
OPR 4,0
OPR 1,0
LIT 5,0
CAL factorial-int,0
OPR 21,0
OPR 0,0

Expected output:

120

Documentation

• Instruction Set — P-Code instructions and their meaning
• Runtime Model — How program execution and runtime state work
• Sample Programs — Additional examples for learning and experimentation

Educational Use

P-Code VM is intended for compiler construction and programming language courses. It provides a way to observe how intermediate instructions are executed, how calls and returns work, and how recursion affects runtime state.