Class Chip8

Chip8

Hierarchy

  • Chip8

Constructors

constructor

Properties

FREQUENCY IS MEMORY_SIZE NUMBER_OF_KEYS PROGRAM_START_ADDRESS REGISTERS SCREEN_HEIGHT SCREEN_WIDTH STACK_SIZE STEPS_PER_CYCLE V cycleCounter delayTimer i keys memory onPlaySound? onRedraw? onStopSound? pc quirks redraw requestAnimationFrameHandle requestInputUpdate screen soundTimer stack stackPointer stepCounter timeoutHandle

Methods

cycle execute fetch fetchN fetchNN fetchNNN fetchX fetchY initialize loadData loadFontSet loadROM playSound run step stop updateTimers

Constructors

constructor

Properties

FREQUENCY

FREQUENCY: number = 60

IS

IS: Chip8IS

Instruction set

MEMORY_SIZE

MEMORY_SIZE: number = 4096

NUMBER_OF_KEYS

NUMBER_OF_KEYS: number = 16

PROGRAM_START_ADDRESS

PROGRAM_START_ADDRESS: number = 0x200

REGISTERS

REGISTERS: number = 16

SCREEN_HEIGHT

SCREEN_HEIGHT: number = 32

SCREEN_WIDTH

SCREEN_WIDTH: number = 64

STACK_SIZE

STACK_SIZE: number = 16

STEPS_PER_CYCLE

STEPS_PER_CYCLE: number = 10

V

V: Uint8Array

Registers: V0 to VF

cycleCounter

cycleCounter: number

Cycle counter (used for debug)

delayTimer

delayTimer: number

Delay timer

i

i: number

Address register

keys

keys: Uint8Array

Keys array

memory

memory: Uint8Array

Memory Layout: 0x000-0x1FF - Chip 8 interpreter (contains font set in emu) 0x050-0x0A0 - Used for the built in 4x5 pixel font set (0-F) 0x200-0xFFF - Program ROM and work RAM

Optional onPlaySound

onPlaySound?: (() => void)

Type declaration

    • (): void

    • Play sound event emitter

      Returns void

Optional onRedraw

onRedraw?: (() => void)

Type declaration

    • (): void

    • Redraw event emitter

      Returns void

Optional onStopSound

onStopSound?: (() => void)

Type declaration

    • (): void

    • Stop sound event emitter

      Returns void

pc

pc: number

Program counter

quirks

quirks: {
    loadStore: boolean;
    shift: boolean;
}

Known "quirks"

Type declaration

  • loadStore: boolean
  • shift: boolean

redraw

redraw: boolean

Redraw screen flag

requestAnimationFrameHandle

requestAnimationFrameHandle: number

window.requestAnimationFrame handle

requestInputUpdate

requestInputUpdate: TypedEvent<void> = ...

Request app to update inputs

screen

screen: Uint8Array

Screen array

soundTimer

soundTimer: number

Sound timer

stack

stack: Uint16Array

Stack array

stackPointer

stackPointer: number

Stack pointer

stepCounter

stepCounter: number

Step counter (used for debug)

timeoutHandle

timeoutHandle: Timeout

CPU run timeout handle

Methods

Private cycle

Private execute

  • Execute opcode

    Parameters

    • opcode: number

    Returns void

Private fetch

  • Fetchs next opcode

    Returns number

    next opcode (2 bytes)

Private fetchN

  • Fetches N symbol

    Parameters

    • opcode: number

    Returns number

    N symbol (0x000N)

Private fetchNN

  • Fetches NN symbol

    Parameters

    • opcode: number

    Returns number

    NN symbol (0x00NN)

Private fetchNNN

  • Fetches NNN symbol

    Parameters

    • opcode: number

    Returns number

    N symbol (0x0NNN)

Private fetchX

  • Fetches X symbol

    Parameters

    • opcode: number

    Returns number

    X symbol (0x0X00)

Private fetchY

  • Fetches Y symbol

    Parameters

    • opcode: number

    Returns number

    Y symbol (0x00Y0)

initialize

Private loadData

  • Load data to memory

    Parameters

    • data: Uint8Array
    • start: number

    Returns void

Private loadFontSet

loadROM

  • Load rom data

    Parameters

    • buffer: Uint8Array

    Returns void

Private playSound

run

Private step

stop

Private updateTimers

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