Emulation

getState

Syntax

emu.getState()

Return value
Table Current emulation state with the following structure:

region: int,
clockRate: int,
cpu: {
  status: int,
  a: int,
  irqFlag: int,
  cycleCount: int,
  pc: int,
  y: int,
  x: int,
  sp: int,
  nmiFlag: bool
},
ppu: {
  cycle: int,
  scanline: int,
  frameCount: int,
  control: {
    backgroundEnabled: bool,
    intensifyBlue: bool,
    intensifyRed: bool,
    backgroundPatternAddr: int,
    grayscale: bool,
    verticalWrite: bool,
    intensifyGreen: bool,
    nmiOnVBlank: bool,
    spritesEnabled: bool,
    spritePatternAddr: int,
    spriteMask: bool,
    largeSprites: bool,
    backgroundMask: bool
  },
  status: {,
    spriteOverflow: bool,
    verticalBlank: bool,
    sprite0Hit: bool
  },
  state: {
    status: int,
    lowBitShift: int,
    xScroll: int,
    highBitShift: int,
    videoRamAddr: int,
    control: int,
    mask: int,
    tmpVideoRamAddr: int,
    writeToggle: bool,
    spriteRamAddr: int
  }  
},
apu: {
  square1: {
    outputVolume: int,
    frequency: float,
    duty: int,
    period: int,
    enabled: bool,
    dutyPosition: int,
    sweepShift: int,
    sweepPeriod: int,
    sweepEnabled: bool,
    sweepNegate: bool
    envelope: {
      counter: int,
      loop: bool,
      divider: int,
      volume: int,
      startFlag: bool,
      constantVolume: bool
    },  
    lengthCounter: {
      halt: bool,
      counter: int,
      reloadValue: int
    }   
  },
  square2: {
    outputVolume: int,
    frequency: float,
    duty: int,
    period: int,
    enabled: bool,
    dutyPosition: int,
    sweepShift: int,
    sweepPeriod: int,
    sweepEnabled: bool,
    sweepNegate: bool,
    envelope: {
      counter: int,
      loop: bool,
      divider: int
      volume: int,
      startFlag: bool,
      constantVolume: bool
    },
    lengthCounter: {
      halt: bool,
      counter: int,
      reloadValue: int
    }   
  },  
  triangle: {
    outputVolume: int,
    frequency: float,
    sequencePosition: int,
    period: int,
    enabled: bool,
    lengthCounter: {
      halt: bool,
      counter: int,
      reloadValue: int
    }   
  },
  noise: {
    modeFlag: bool,
    enabled: bool,
    outputVolume: int,
    frequency: float,
    period: int,
    shiftRegister: int,
    envelope: {
      counter: int,
      loop: bool,
      divider: int,
      volume: int,
      startFlag: bool,
      constantVolume: bool
    },  
    lengthCounter: {
      halt: bool,
      counter: int,
      reloadValue: int
    }
  },
  dmc: {
    sampleLength: int,
    irqEnabled: bool,
    loop: bool,
    outputVolume: int,
    bytesRemaining: int,
    sampleAddr: int,
    period: int,
    sampleRate: float
  },  
  frameCounter: {
    fiveStepMode: int,
    irqEnabled: int,
    sequencePosition: int
  }  
},
cart: {
  selectedPrgPages: array,
  chrRomSize: int,
  chrRamSize: int,
  prgPageCount: int,
  chrPageSize: int,
  selectedChrPages: array,
  chrPageCount: int,
  prgRomSize: int,
  prgPageSize: int,
}

Description
Return a table containing information about the state of the CPU, PPU, APU and cartridge.

setState

Syntax

emu.setState(state)

Parameters
state - Table A table containing the state of the emulation to apply.

Return value
None

Description
Updates the CPU and PPU’s state. The state parameter must be a table in the same format as the one returned by getState()
Note: the state of the APU or cartridge cannot be modified by using setState().

breakExecution

Syntax

emu.breakExecution()

Return value
None

Description
Breaks the execution of the game and displays the debugger window.

execute

Syntax

emu.execute(count, type)

Parameters
count - Integer The number of cycles or instructions to run before breaking
type - Enum See executeCountType

Return value
None

Description
Runs the emulator for the specified number of cycles/instructions and then breaks the execution.

reset

Syntax

emu.reset()

Return value
None

Description
Resets the current game.

resume

Syntax

emu.resume()

Return value
None

Description
Resumes execution after breaking.

rewind

Syntax

emu.rewind(seconds)

Parameters
seconds - Integer The number of seconds to rewind

Return value
None

Description
Instantly rewinds the emulation by the number of seconds specified.
Note: this can only be called from within a “StartFrame” event callback.