broken-neees/lib/Mapper.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); }
/**
 * An abstract class that represents a generic mapper.
 * It's connected to two different memory areas:
 * - CPU $4020-$FFFF (for PRG ROM, PRG RAM, and mapper registers)
 * - PPU $0000-$1FFF (for CHR ROM / Pattern tables)
 */
var Mapper = /*#__PURE__*/function () {
  function Mapper(cpu, ppu, cartridge) {
    _classCallCheck(this, Mapper);
    this.cpu = cpu;
    this.ppu = ppu;
    this.cartridge = cartridge;
    var prg = this.cartridge.prg();
    var chr = this.cartridge.chr();
    var totalPrgPages = Math.floor(prg.length / this.prgRomPageSize());
    var totalChrPages = Math.floor(chr.length / this.chrRomPageSize());
    this.prgPages = [];
    for (var i = 0; i < totalPrgPages; i++) this.prgPages.push(this._getPage(prg, this.prgRomPageSize(), i));
    this.chrPages = [];
    for (var _i = 0; _i < totalChrPages; _i++) this.chrPages.push(this._getPage(chr, this.chrRomPageSize(), _i));
    this.onLoad();
  }

  /** Returns the PRG ROM page size (in bytes). */
  _createClass(Mapper, [{
    key: "prgRomPageSize",
    value: function prgRomPageSize() {
      return 16 * 1024;
    }

    /** Returns the CHR ROM page size (in bytes). */
  }, {
    key: "chrRomPageSize",
    value: function chrRomPageSize() {
      return 8 * 1024;
    }

    /** Called when instantiating the mapper. */
  }, {
    key: "onLoad",
    value: function onLoad() {}

    /** Maps a CPU read operation (`address` is in CPU range $4020-$FFFF). */
  }, {
    key: "cpuRead",
    value: function cpuRead( /*address*/
    ) {
      throw new Error("not_implemented");
    }

    /** Maps a CPU write operation (`address` is in CPU range $4020-$FFFF). */
  }, {
    key: "cpuWrite",
    value: function cpuWrite( /*address, value*/
    ) {
      throw new Error("not_implemented");
    }

    /** Maps a PPU read operation (`address` is in PPU range $0000-$1FFF). */
  }, {
    key: "ppuRead",
    value: function ppuRead( /*address*/
    ) {
      throw new Error("not_implemented");
    }

    /** Maps a PPU write operation (`address` is in PPU range $0000-$1FFF). */
  }, {
    key: "ppuWrite",
    value: function ppuWrite( /*address, value*/
    ) {
      throw new Error("not_implemented");
    }

    /**
     * Runs at cycle 260 of every scanline (including preline).
     */
  }, {
    key: "tick",
    value: function tick() {}

    /** Returns a snapshot of the current state. */
  }, {
    key: "getSaveState",
    value: function getSaveState() {
      return {
        chrPages: this.cartridge.header.usesChrRam ? this.chrPages.map(function (it) {
          return Array.from(it);
        }) : null
      };
    }

    /** Restores state from a snapshot. */
  }, {
    key: "setSaveState",
    value: function setSaveState(saveState) {
      if (saveState.chrPages != null) this.chrPages = saveState.chrPages.map(function (it) {
        return new Uint8Array(it);
      });
    }

    /** Returns a PRG `page`, wrapping if needed. */
  }, {
    key: "$getPrgPage",
    value: function $getPrgPage(page) {
      return this.prgPages[Math.max(0, page % this.prgPages.length)];
    }

    /** Returns a CHR `page`, wrapping if needed. */
  }, {
    key: "$getChrPage",
    value: function $getChrPage(page) {
      return this.chrPages[Math.max(0, page % this.chrPages.length)];
    }
  }, {
    key: "_getPage",
    value: function _getPage(memory, pageSize, page) {
      var offset = page * pageSize;
      return memory.slice(offset, offset + pageSize);
    }
  }]);
  return Mapper;
}();
exports.default = Mapper;