nes-emu/apu/registers/PulseSweep.js

A NES emulator

"use strict";

Object.defineProperty(exports, "__esModule", {
  value: true
});
exports.default = void 0;
var _registers = require("../../registers");
/** Controls the frequency sweeper of a Pulse channel. */
class PulseSweep extends _registers.WriteOnlyInMemoryRegister {
  constructor(id) {
    super();
    this.id = id;
    this.addReadOnlyField("shiftCount", 0, 3).addReadOnlyField("negateFlag", 3).addReadOnlyField("dividerPeriodMinusOne", 4, 3).addReadOnlyField("enabledFlag", 7);
  }

  /** Sets the start flag of the frequency sweeper. */
  writeAt(__, byte) {
    this.setValue(byte);
    const channel = this.context.apu.channels.pulses[this.id];
    channel.frequencySweeper.startFlag = true;
  }
}
exports.default = PulseSweep;