#ifndef OPCODES_H
#define OPCODES_H

// Define opcodes for the Virtual Machine.
// Each opcode is an integer constant used by the VM.
enum {
    OP_HALT = 0,       // Stop execution.
    OP_PUSH,           // Push an immediate value onto the stack. (Operand: value)
    OP_POP,            // Pop the top of the stack into a register. (Operand: register index)
    OP_LOAD,           // Load an immediate value into a register. (Operands: register, value)
    OP_ADD,            // Add two registers; store the result in the first register. (Operands: reg_dest, reg_src)
    OP_SUB,            // Subtract second register from first; store result in the first register. (Operands: reg_dest, reg_src)
    OP_MUL,            // Multiply two registers; store result in the first register. (Operands: reg_dest, reg_src)
    OP_DIV,            // Divide first register by second; store result in the first register. (Operands: reg_dest, reg_src)
    OP_PRINT,          // Print the value of a register. (Operand: register index)
    OP_JMP,            // Unconditional jump to a specified program address. (Operand: address)
    OP_JMPZ,           // Jump to a specified address if the given register is zero. (Operands: register, address)
    OP_CALL,           // Call a function: push return address and jump. (Operand: address)
    OP_RET,            // Return from a function call. (No operand)
    OP_CALL_OS         // Enter the nested OS shell. (No operand)
};

#endif // OPCODES_H