broken-neees/ppu/PPUMemory.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;
var _mirroringTypes = _interopRequireDefault(require("../lib/ppu/mirroringTypes"));
function _interopRequireDefault(obj) { return obj && obj.__esModule ? obj : { default: obj }; }
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 VRAM_SIZE = 4096;
var PALETTE_RAM_SIZE = 32;
var OAM_RAM_SIZE = 256;
var PPUMemory = /*#__PURE__*/function () {
  function PPUMemory() {
    _classCallCheck(this, PPUMemory);
    this.vram = new Uint8Array(VRAM_SIZE);
    this.paletteRam = new Uint8Array(PALETTE_RAM_SIZE);
    this.oamRam = new Uint8Array(OAM_RAM_SIZE);
    this.mirroringId = null;
  }
  _createClass(PPUMemory, [{
    key: "onLoad",
    value: function onLoad(cartridge, mapper) {
      this.cartridge = cartridge;
      this.mapper = mapper;
      this.changeNameTableMirroringTo(cartridge.header.mirroringId);
    }
  }, {
    key: "changeNameTableMirroringTo",
    value: function changeNameTableMirroringTo(mirroringId) {
      if (this.cartridge.header.mirroringId === "FOUR_SCREEN") mirroringId = "FOUR_SCREEN";
      this.mirroringId = mirroringId;
      this._mirroring = _mirroringTypes.default[mirroringId];
    }
  }, {
    key: "read",
    value: function read(address) {
      // Pattern tables 0 and 1 (mapper)
      if (address <= 0x1fff) return this.mapper.ppuRead(address);

      // Name tables 0 to 3 (VRAM + mirror)
      if (address >= 0x2000 && address <= 0x2fff) {
        if (address >= 0x2000 && address < 0x2400) return this.vram[this._mirroring.$2000 + address - 0x2000];
        if (address >= 0x2400 && address < 0x2800) return this.vram[this._mirroring.$2400 + address - 0x2400];
        if (address >= 0x2800 && address < 0x2c00) return this.vram[this._mirroring.$2800 + address - 0x2800];
        if (address >= 0x2c00 && address < 0x3000) return this.vram[this._mirroring.$2C00 + address - 0x2c00];
      }

      // Mirrors of $2000-$2EFF
      if (address >= 0x3000 && address <= 0xeff) return this.read(0x2000 + (address - 0x3000) % 0x1000);

      // Palette RAM indexes
      if (address >= 0x3f00 && address <= 0x3f1f) {
        if (address === 0x3f10) return this.read(0x3f00);
        if (address === 0x3f14) return this.read(0x3f04);
        if (address === 0x3f18) return this.read(0x3f08);
        if (address === 0x3f1c) return this.read(0x3f0c);
        return this.paletteRam[address - 0x3f00];
      }

      // Mirrors of $3F00-$3F1F
      if (address >= 0x3f20 && address <= 0x3fff) return this.read(0x3f00 + (address - 0x3f20) % 0x0020);
      return 0;
    }
  }, {
    key: "write",
    value: function write(address, value) {
      // Pattern tables 0 and 1 (mapper)
      if (address <= 0x1fff) return this.mapper.ppuWrite(address, value);

      // Name tables 0 to 3 (VRAM + mirror)
      if (address >= 0x2000 && address <= 0x2fff) {
        if (address >= 0x2000 && address < 0x2400) return this.vram[this._mirroring.$2000 + address - 0x2000] = value;
        if (address >= 0x2400 && address < 0x2800) return this.vram[this._mirroring.$2400 + address - 0x2400] = value;
        if (address >= 0x2800 && address < 0x2c00) return this.vram[this._mirroring.$2800 + address - 0x2800] = value;
        if (address >= 0x2c00 && address < 0x3000) return this.vram[this._mirroring.$2C00 + address - 0x2c00] = value;
      }

      // Mirrors of $2000-$2EFF
      if (address >= 0x3000 && address <= 0xeff) return this.write(0x2000 + (address - 0x3000) % 0x1000, value);

      // Palette RAM indexes
      if (address >= 0x3f00 && address <= 0x3f1f) {
        if (address === 0x3f10) return this.write(0x3f00, value);
        if (address === 0x3f14) return this.write(0x3f04, value);
        if (address === 0x3f18) return this.write(0x3f08, value);
        if (address === 0x3f1c) return this.write(0x3f0c, value);
        return this.paletteRam[address - 0x3f00] = value;
      }

      // Mirrors of $3F00-$3F1F
      if (address >= 0x3f20 && address <= 0x3fff) return this.write(0x3f00 + (address - 0x3f20) % 0x0020, value);
    }
  }]);
  return PPUMemory;
}();
exports.default = PPUMemory;