CommaVideo scheme support.

src/machine/stella/cartridge/CartridgeCV.ts

@@ -0,0 +1,106 @@
+/*
+ *   This file is part of 6502.ts, an emulator for 6502 based systems built
+ *   in Typescript.
+ *
+ *   Copyright (C) 2014 - 2018 Christian Speckner & contributors
+ *
+ *   This program is free software; you can redistribute it and/or modify
+ *   it under the terms of the GNU General Public License as published by
+ *   the Free Software Foundation; either version 2 of the License, or
+ *   (at your option) any later version.
+ *
+ *   This program is distributed in the hope that it will be useful,
+ *   but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *   GNU General Public License for more details.
+ *
+ *   You should have received a copy of the GNU General Public License along
+ *   with this program; if not, write to the Free Software Foundation, Inc.,
+ *   51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+import AbstractCartridge from './AbstractCartridge';
+import CartridgeInfo from './CartridgeInfo';
+import RngGeneratorInterface from '../../../tools/rng/GeneratorInterface';
+import Bus from '../Bus';
+import { BufferInterface, searchForSignatures } from './util';
+
+class CartridgeCV extends AbstractCartridge {
+    constructor(buffer: { [i: number]: number; length: number }) {
+        super();
+
+        if (buffer.length !== 0x0800) {
+            throw new Error(`buffer is not a 2k cartridge image: wrong length ${buffer.length}`);
+        }
+
+        for (let i = 0; i < 0x0800; i++) {
+            this._rom[i] = buffer[i];
+        }
+    }
+
+    static matchesBuffer(buffer: BufferInterface): boolean {
+        // Signatures shamelessly stolen from Stella
+        const signatureCounts = searchForSignatures(buffer, [[0x9d, 0xff, 0xf3], [0x99, 0x00, 0xf4]]);
+
+        return signatureCounts[0] > 0 || signatureCounts[1] > 0;
+    }
+
+    setBus(bus: Bus): this {
+        this._bus = bus;
+
+        return this;
+    }
+
+    randomize(rng: RngGeneratorInterface): void {
+        for (let i = 0; i < 0x0400; i++) {
+            this._ram[i] = rng.int(0xff);
+        }
+    }
+
+    read(address: number): number {
+        address &= 0x0fff;
+
+        if (address < 0x0400) {
+            return this._ram[address];
+        }
+
+        if (address < 0x0800) {
+            return (this._ram[address & 0x03ff] = this._bus.getLastDataBusValue());
+        }
+
+        return this._rom[address & 0x07ff];
+    }
+
+    write(address: number, value: number): void {
+        address &= 0x0fff;
+
+        if (address >= 0x0400 && address < 0x0800) {
+            this._ram[address & 0x03ff] = value;
+        }
+    }
+
+    peek(address: number): number {
+        address &= 0x0fff;
+
+        if (address < 0x0400) {
+            return this._ram[address];
+        }
+
+        if (address < 0x0800) {
+            return 0;
+        }
+
+        return this._rom[address & 0x07ff];
+    }
+
+    getType(): CartridgeInfo.CartridgeType {
+        return CartridgeInfo.CartridgeType.bankswitch_2k_cv;
+    }
+
+    private _rom = new Uint8Array(0x0800);
+    private _ram = new Uint8Array(0x0400);
+
+    private _bus: Bus;
+}
+
+export default CartridgeCV;

src/machine/stella/cartridge/CartridgeDetector.ts

@@ -33,14 +33,15 @@ import CartridgeDPCPlus from './CartridgeDPCPlus';
 import CartridgeCDF from './CartridgeCDF';
 import Cartridge8040 from './Cartridge0840';
 import * as cartridgeUtil from './util';
+import CartridgeCV from './CartridgeCV';
 
 class CartridgeDetector {
     detectCartridgeType(buffer: cartridgeUtil.BufferInterface): CartridgeInfo.CartridgeType {
         if (buffer.length % 8448 === 0) {
             return CartridgeInfo.CartridgeType.bankswitch_supercharger;
         }
 
-        if (buffer.length <= 0x0800) {
+        if (buffer.length < 0x0800) {
             return CartridgeInfo.CartridgeType.vanilla_2k;
         }
 
@@ -49,6 +50,9 @@ class CartridgeDetector {
         }
 
         switch (buffer.length) {
+            case 0x0800:
+                return this._detect2k(buffer);
+
             case 0x1000:
                 return CartridgeInfo.CartridgeType.vanilla_4k;
 
@@ -78,6 +82,14 @@ class CartridgeDetector {
         }
     }
 
+    private _detect2k(buffer: cartridgeUtil.BufferInterface): CartridgeInfo.CartridgeType {
+        if (CartridgeCV.matchesBuffer(buffer)) {
+            return CartridgeInfo.CartridgeType.bankswitch_2k_cv;
+        }
+
+        return CartridgeInfo.CartridgeType.vanilla_2k;
+    }
+
     private _detect8k(buffer: cartridgeUtil.BufferInterface): CartridgeInfo.CartridgeType {
         const f8Matches = CartridgeF8.matchesBuffer(buffer);
 

src/machine/stella/cartridge/CartridgeFactory.ts

@@ -21,6 +21,7 @@
 
 import Cartridge2k from './Cartridge2k';
 import Cartridge4k from './Cartridge4k';
+import CartridgeCV from './CartridgeCV';
 import CartridgeF8 from './CartridgeF8';
 import CartridgeF6 from './CartridgeF6';
 import CartridgeE0 from './CartridgeE0';
@@ -73,6 +74,9 @@ export default class CartridgeFactory {
             case CartridgeInfo.CartridgeType.vanilla_4k:
                 return new Cartridge4k(buffer);
 
+            case CartridgeInfo.CartridgeType.bankswitch_2k_cv:
+                return new CartridgeCV(buffer);
+
             case CartridgeInfo.CartridgeType.bankswitch_8k_F8:
                 return new CartridgeF8(buffer);
 

src/machine/stella/cartridge/CartridgeInfo.ts

@@ -24,6 +24,8 @@ namespace CartridgeInfo {
         vanilla_2k = 'vanilla_2k',
         vanilla_4k = 'vanilla_4k',
 
+        bankswitch_2k_cv = 'bankswitch_2k_cv',
+
         bankswitch_8k_F8 = 'bankswitch_8k_F8',
         bankswitch_8k_E0 = 'bankswitch_8k_E0',
         bankswitch_8k_3F = 'bankswitch_8k_3F',
@@ -56,6 +58,7 @@ namespace CartridgeInfo {
         return [
             CartridgeType.vanilla_2k,
             CartridgeType.vanilla_4k,
+            CartridgeType.bankswitch_2k_cv,
             CartridgeType.bankswitch_8k_F8,
             CartridgeType.bankswitch_8k_E0,
             CartridgeType.bankswitch_8k_3F,
@@ -86,6 +89,9 @@ namespace CartridgeInfo {
             case CartridgeType.vanilla_4k:
                 return 'plain 4k';
 
+            case CartridgeType.bankswitch_2k_cv:
+                return '2k CommaVideo scheme';
+
             case CartridgeType.bankswitch_8k_F8:
                 return 'bankswitched 8k, F8 (Atari) scheme';