Computer

1. Computer Chip

The Computer chip is the top-level architecture of the Hack platform. It integrates the CPU, Memory, and Program Counter (PC). It fetches instructions from the ROM (instruction memory), executes them via the CPU, and stores or retrieves data via the Memory chip.

The Computer chip supports:

Instruction fetching

Memory reads/writes

Program flow control (jump, reset, halt, etc.)

2. Truth Table

ROM[instruction]	Memory[inM]	load	reset	Result
C-instruction	valid input	1	0	Performs ALU computation, stores result
A-instruction	x	0	0	Loads constant/address into A register
x	x	x	1	Resets the Program Counter to 0

3. Implementation (HDL)

The Computer chip connects:

CPU

Memory

ROM32K (for instructions)

It routes the instruction into the CPU, the memory data into the CPU, and output signals from the CPU into Memory and the PC.

CHIP Computer {
    IN reset;
    
    PARTS:
    // Instruction ROM (holds the program)
    ROM32K(address=pc, out=instruction);

    // Memory (RAM + Screen + Keyboard)
    Memory(in=outM, load=writeM, address=addressM, out=inM);

    // CPU (central processor)
    CPU(
        inM=inM,
        instruction=instruction,
        reset=reset,
        outM=outM,
        writeM=writeM,
        addressM=addressM,
        pc=pc
    );
}