Fix save-state serialization of CPU dataBus and controller state

src/controller.d.ts

@@ -2,9 +2,31 @@ export type ButtonKey = 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9;
 
 export class Controller {
   state: number[];
+  baseA: number;
+  baseB: number;
+  turboA: boolean;
+  turboB: boolean;
+  turboToggle: boolean;
+
   buttonDown: (key: ButtonKey) => void;
   buttonUp: (key: ButtonKey) => void;
   clock: () => void;
+  toJSON(): {
+    state: number[];
+    baseA: number;
+    baseB: number;
+    turboA: boolean;
+    turboB: boolean;
+    turboToggle: boolean;
+  };
+  fromJSON(state: {
+    state: number[];
+    baseA: number;
+    baseB: number;
+    turboA: boolean;
+    turboB: boolean;
+    turboToggle: boolean;
+  }): void;
 
   static readonly BUTTON_A = 0;
   static readonly BUTTON_B = 1;
@@ -16,4 +38,12 @@ export class Controller {
   static readonly BUTTON_RIGHT = 7;
   static readonly BUTTON_TURBO_A = 8;
   static readonly BUTTON_TURBO_B = 9;
+  static readonly JSON_PROPERTIES: readonly [
+    "state",
+    "baseA",
+    "baseB",
+    "turboA",
+    "turboB",
+    "turboToggle",
+  ];
 }

src/controller.js

@@ -1,3 +1,5 @@
+import { fromJSON, toJSON } from "./utils.js";
+
 class Controller {
   static BUTTON_A = 0;
   static BUTTON_B = 1;
@@ -65,6 +67,23 @@ class Controller {
       this.state[Controller.BUTTON_B] = this.turboToggle ? 0x41 : 0x40;
     }
   }
+
+  static JSON_PROPERTIES = [
+    "state",
+    "baseA",
+    "baseB",
+    "turboA",
+    "turboB",
+    "turboToggle",
+  ];
+
+  toJSON() {
+    return toJSON(this);
+  }
+
+  fromJSON(s) {
+    fromJSON(this, s);
+  }
 }
 
 export default Controller;

src/cpu.js

@@ -2022,6 +2022,7 @@ class CPU {
     "F_BRK",
     "F_BRK_NEW",
     "_cpuCycleBase",
+    "dataBus",
   ];
 
   toJSON() {

src/nes.js

@@ -182,6 +182,10 @@ class NES {
       mmap: this.mmap.toJSON(),
       ppu: this.ppu.toJSON(),
       papu: this.papu.toJSON(),
+      controllers: {
+        1: this.controllers[1].toJSON(),
+        2: this.controllers[2].toJSON(),
+      },
     };
   }
 
@@ -192,6 +196,11 @@ class NES {
     this.mmap.fromJSON(s.mmap);
     this.ppu.fromJSON(s.ppu);
     this.papu.fromJSON(s.papu);
+
+    if (s.controllers) {
+      this.controllers[1].fromJSON(s.controllers[1]);
+      this.controllers[2].fromJSON(s.controllers[2]);
+    }
   }
 }
 

test/nes.spec.js

@@ -151,6 +151,34 @@ describe("NES", function () {
     });
   });
 
+  describe("save state serialization", function () {
+    it("preserves cpu dataBus and controller state", function () {
+      let nes = new NES();
+      let data = fs.readFileSync("roms/croom/croom.nes");
+      nes.loadROM(data.toString("binary"));
+
+      nes.cpu.dataBus = 0xab;
+      nes.buttonDown(1, 0); // A
+      nes.buttonDown(1, 8); // turbo A
+      nes.controllers[1].clock();
+
+      const state = nes.toJSON();
+
+      let restored = new NES();
+      restored.loadROM(data.toString("binary"));
+      restored.fromJSON(state);
+
+      assert.strictEqual(restored.cpu.dataBus, 0xab);
+      assert.deepStrictEqual(restored.controllers[1].state, nes.controllers[1].state);
+      assert.strictEqual(restored.controllers[1].baseA, nes.controllers[1].baseA);
+      assert.strictEqual(restored.controllers[1].turboA, nes.controllers[1].turboA);
+      assert.strictEqual(
+        restored.controllers[1].turboToggle,
+        nes.controllers[1].turboToggle,
+      );
+    });
+  });
+
   describe("#getFPS()", function () {
     let nes = new NES();
     before(function () {