broken-neees/apu/FrequencySweep.js

A really broken NEEES emulator that introduces glitches and random bugs on purpose!

"use strict";

Object.defineProperty(exports, "__esModule", {
  value: true
});
exports.default = void 0;
function _typeof(obj) { "@babel/helpers - typeof"; return _typeof = "function" == typeof Symbol && "symbol" == typeof Symbol.iterator ? function (obj) { return typeof obj; } : function (obj) { return obj && "function" == typeof Symbol && obj.constructor === Symbol && obj !== Symbol.prototype ? "symbol" : typeof obj; }, _typeof(obj); }
function _classCallCheck(instance, Constructor) { if (!(instance instanceof Constructor)) { throw new TypeError("Cannot call a class as a function"); } }
function _defineProperties(target, props) { for (var i = 0; i < props.length; i++) { var descriptor = props[i]; descriptor.enumerable = descriptor.enumerable || false; descriptor.configurable = true; if ("value" in descriptor) descriptor.writable = true; Object.defineProperty(target, _toPropertyKey(descriptor.key), descriptor); } }
function _createClass(Constructor, protoProps, staticProps) { if (protoProps) _defineProperties(Constructor.prototype, protoProps); if (staticProps) _defineProperties(Constructor, staticProps); Object.defineProperty(Constructor, "prototype", { writable: false }); return Constructor; }
function _toPropertyKey(arg) { var key = _toPrimitive(arg, "string"); return _typeof(key) === "symbol" ? key : String(key); }
function _toPrimitive(input, hint) { if (_typeof(input) !== "object" || input === null) return input; var prim = input[Symbol.toPrimitive]; if (prim !== undefined) { var res = prim.call(input, hint || "default"); if (_typeof(res) !== "object") return res; throw new TypeError("@@toPrimitive must return a primitive value."); } return (hint === "string" ? String : Number)(input); }
var APU_MIN_TIMER = 8;
var APU_MAX_TIMER = 0x7ff;
var FrequencySweep = /*#__PURE__*/function () {
  function FrequencySweep(channel) {
    _classCallCheck(this, FrequencySweep);
    this.channel = channel;

    // input
    this.startFlag = false;

    // output
    this.dividerCount = 0;
    this.mute = false;
  }
  _createClass(FrequencySweep, [{
    key: "clock",
    value: function clock() {
      var register = this.channel.registers.sweep;
      if (register.enabledFlag && register.shiftCount > 0 && this.dividerCount === 0 && !this.mute) {
        var sweepDelta = this.channel.timer >> register.shiftCount;
        this.channel.timer += sweepDelta * (register.negateFlag ? -1 : 1);
      }
      if (this.dividerCount === 0 || this.startFlag) {
        this.dividerCount = register.dividerPeriodMinusOne + 1;
        this.startFlag = false;
      } else this.dividerCount--;
    }
  }, {
    key: "muteIfNeeded",
    value: function muteIfNeeded() {
      this.mute = this.channel.timer < APU_MIN_TIMER || this.channel.timer > APU_MAX_TIMER;
    }
  }]);
  return FrequencySweep;
}();
exports.default = FrequencySweep;