From c033bad0b959b26f0be310d097d210ab729912bf Mon Sep 17 00:00:00 2001
From: Thomas Harte <thomas.harte@gmail.com>
Date: Sat, 18 Mar 2017 20:51:49 -0400
Subject: [PATCH] Here's MNetwork!

---
 Machines/Atari2600/Atari2600.cpp              |  2 +
 Machines/Atari2600/CartridgeMNetwork.hpp      | 68 +++++++++++++++++++
 .../Clock Signal.xcodeproj/project.pbxproj    |  2 +
 3 files changed, 72 insertions(+)
 create mode 100644 Machines/Atari2600/CartridgeMNetwork.hpp

diff --git a/Machines/Atari2600/Atari2600.cpp b/Machines/Atari2600/Atari2600.cpp
index 40457ca7f..3d6bea78c 100644
--- a/Machines/Atari2600/Atari2600.cpp
+++ b/Machines/Atari2600/Atari2600.cpp
@@ -17,6 +17,7 @@
 #include "CartridgeCBSRAMPlus.hpp"
 #include "CartridgeCommaVid.hpp"
 #include "CartridgeMegaBoy.hpp"
+#include "CartridgeMNetwork.hpp"
 #include "CartridgeParkerBros.hpp"
 #include "CartridgeTigervision.hpp"
 #include "CartridgeUnpaged.hpp"
@@ -88,6 +89,7 @@ void Machine::configure_as_target(const StaticAnalyser::Target &target) {
 		case StaticAnalyser::Atari2600PagingModel::Tigervision:		bus_.reset(new CartridgeTigervision(rom));		break;
 		case StaticAnalyser::Atari2600PagingModel::CBSRamPlus:		bus_.reset(new CartridgeCBSRAMPlus(rom));		break;
 		case StaticAnalyser::Atari2600PagingModel::MegaBoy:			bus_.reset(new CartridgeMegaBoy(rom));			break;
+		case StaticAnalyser::Atari2600PagingModel::MNetwork:		bus_.reset(new CartridgeMNetwork(rom));			break;
 		case StaticAnalyser::Atari2600PagingModel::Atari8k:
 			if(target.atari.uses_superchip) {
 				bus_.reset(new CartridgeAtari8kSuperChip(rom));
diff --git a/Machines/Atari2600/CartridgeMNetwork.hpp b/Machines/Atari2600/CartridgeMNetwork.hpp
new file mode 100644
index 000000000..fcd392d36
--- /dev/null
+++ b/Machines/Atari2600/CartridgeMNetwork.hpp
@@ -0,0 +1,68 @@
+//
+//  CartridgeMNetwork.h
+//  Clock Signal
+//
+//  Created by Thomas Harte on 18/03/2017.
+//  Copyright © 2017 Thomas Harte. All rights reserved.
+//
+
+#ifndef Atari2600_CartridgeMNetwork_hpp
+#define Atari2600_CartridgeMNetwork_hpp
+
+#include "Cartridge.hpp"
+
+namespace Atari2600 {
+
+class CartridgeMNetwork: public Cartridge<CartridgeMNetwork> {
+	public:
+		CartridgeMNetwork(const std::vector<uint8_t> &rom) :
+			Cartridge(rom) {
+			rom_ptr_[0] = rom_.data() + rom_.size() - 4096;
+			rom_ptr_[1] = rom_ptr_[0] + 2048;
+			high_ram_ptr_ = high_ram_;
+		}
+
+		void perform_bus_operation(CPU6502::BusOperation operation, uint16_t address, uint8_t *value) {
+			address &= 0x1fff;
+			if(!(address & 0x1000)) return;
+
+			if(address >= 0x1fe0 && address <= 0x1fe6) {
+				rom_ptr_[0] = rom_.data() + (address - 0x1fe0) * 2048;
+			} else if(address == 0x1fe7) {
+				rom_ptr_[0] = nullptr;
+			} else if(address >= 0x1ff8 && address <= 0x1ffb) {
+				int offset = (address - 0x1ff8) * 256;
+				high_ram_ptr_ = &high_ram_[offset];
+			}
+
+			if(address & 0x800) {
+				if(address < 0x1900) {
+					high_ram_ptr_[address & 255] = *value;
+				} else if(address < 0x1a00) {
+					if(isReadOperation(operation)) *value = high_ram_ptr_[address & 255];
+				} else {
+					if(isReadOperation(operation)) *value = rom_ptr_[1][address & 2047];
+				}
+			} else {
+				if(rom_ptr_[0]) {
+					if(isReadOperation(operation)) *value = rom_ptr_[0][address & 2047];
+				} else {
+					if(address < 0x1400) {
+						low_ram_[address & 1023] = *value;
+					} else {
+						if(isReadOperation(operation)) *value = low_ram_[address & 1023];
+					}
+				}
+			}
+
+		}
+
+	private:
+		uint8_t *rom_ptr_[2];
+		uint8_t *high_ram_ptr_;
+		uint8_t low_ram_[1024], high_ram_[1024];
+};
+
+}
+
+#endif /* Atari2600_CartridgeMNetwork_hpp */
diff --git a/OSBindings/Mac/Clock Signal.xcodeproj/project.pbxproj b/OSBindings/Mac/Clock Signal.xcodeproj/project.pbxproj
index d4e620bc5..450d31b92 100644
--- a/OSBindings/Mac/Clock Signal.xcodeproj/project.pbxproj	
+++ b/OSBindings/Mac/Clock Signal.xcodeproj/project.pbxproj	
@@ -951,6 +951,7 @@
 		4BEAC07C1E7DEA6B00EE56B2 /* CartridgeTigervision.hpp */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.cpp.h; path = CartridgeTigervision.hpp; sourceTree = "<group>"; };
 		4BEAC07D1E7DF13E00EE56B2 /* CartridgeCBSRAMPlus.hpp */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.cpp.h; path = CartridgeCBSRAMPlus.hpp; sourceTree = "<group>"; };
 		4BEAC07E1E7DF2D000EE56B2 /* CartridgeMegaBoy.hpp */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.cpp.h; path = CartridgeMegaBoy.hpp; sourceTree = "<group>"; };
+		4BEAC07F1E7DF45900EE56B2 /* CartridgeMNetwork.hpp */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.cpp.h; path = CartridgeMNetwork.hpp; sourceTree = "<group>"; };
 		4BEE0A6A1D72496600532C7B /* Cartridge.cpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.cpp; path = Cartridge.cpp; sourceTree = "<group>"; };
 		4BEE0A6B1D72496600532C7B /* Cartridge.hpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.h; path = Cartridge.hpp; sourceTree = "<group>"; };
 		4BEE0A6D1D72496600532C7B /* PRG.cpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.cpp; path = PRG.cpp; sourceTree = "<group>"; };
@@ -1132,6 +1133,7 @@
 				4BEA52671DF34909007E74F2 /* PIA.hpp */,
 				4BEA52651DF3472B007E74F2 /* Speaker.hpp */,
 				4BE7C9171E3D397100A5496D /* TIA.hpp */,
+				4BEAC07F1E7DF45900EE56B2 /* CartridgeMNetwork.hpp */,
 			);
 			path = Atari2600;
 			sourceTree = "<group>";