Exercise 48: A Tiny Virtual Machine – Part 1: Spec & Loader

Goals:

• Understand how to design a simple CPU spec.
• Implement a bytecode file format.
• Load programs into memory.

Topics Covered:

• Defining a simple instruction set: LOAD, ADD, SUB, JMP, HLT.
• Building the memory array.
• Writing a file format: 16-bit opcodes + operand bytes.
• Implementing a loader in C that reads this bytecode into memory.

Code Concepts:

cCopyEdittypedef struct {
    unsigned char *code;
    int ip;  // instruction pointer
    int running;
} VM;