IKP 2002

📖 Overview

IKP 2002 is a small experimental CPU written in C++. It was not designed to be perfect or fully accurate, but rather to explore and better understand low-level concepts such as registers, instructions, flags, and basic processor logic.

This project is a handcrafted attempt to simulate how a CPU behaves at a very fundamental level. Instructions are interpreted in real time through a command-line interface, and the syntax was intentionally designed to resemble modern assembly as closely as possible while remaining simple and understandable.

Originally planned as a 2-bit processor, the project evolved into a more flexible experimental system. Instead of forcing strict limitations, the focus shifted toward learning, experimentation, and understanding how everything connects internally.

🎯 Purpose

IKP 2002 was built to:

• understand how registers work

• see how instructions are parsed and executed

• explore ALU-style operations

• understand why CPUs need flags

• experiment with assembly-like syntax in a controlled environment

This is not a cycle-accurate CPU or a hardware-level emulator. It is a real-time interpreted CPU model, where each instruction is manually entered and executed immediately.

🧩 Architecture

Registers

The processor includes 4 general-purpose registers:

• AX

• BX

• CX

• DX

All registers are implemented as standard integers (int), meaning the system is not strictly limited to 2-bit values in practice.

Flags

The CPU uses 3 main flags:

• ZERO → values are equal

• GREATER → left value is greater

• LESS → left value is smaller

These flags are set after the CMP instruction and are meant to simulate basic decision-making logic.

Initialization

The CPU starts in a waiting state and requires:

START

to begin execution.

To exit:

>EXIT

⚙️ Instruction Set

MOV

Moves a value into a register.

MOV AX 2

MOV BX 7

• MOV AX 2 → AX = 2

• MOV BX 7 → BX = 7

Note: This version does not support register-to-register moves.

PRINT

Outputs register values.

PRINT AX

PRINT ALL

• PRINT AX → prints AX

• PRINT ALL → prints all registers

This is mainly a debugging / inspection tool.

ADD

Adds a value or register to another register.

ADD AX, BX

ADD AX, 1

• ADD AX, BX → AX = AX + BX

• ADD AX, 1 → AX = AX + 1

SUB

Subtracts a value or register.

SUB AX, BX

SUB AX, 1

• SUB AX, BX → AX = AX - BX

• SUB AX, 1 → AX = AX - 1

INC

Increments a register by 1.

INC AX

• AX = AX + 1

DEC

Decrements a register by 1.

DEC BX

• BX = BX - 1

CMP

Compares two values and sets flags.

CMP AX, BX

CMP AX, 2

This instruction:

• does NOT modify registers

• only sets flags

Result logic: