prelim mbc work

src/addressSpace.hpp

@@ -0,0 +1,77 @@
+#ifndef ADDRESSSPACE_HPP
+#define ADDRESSSPACE_HPP
+#include <fstream>
+#include <filesystem>
+#include <cstdint>
+#include <cstring>
+#include <string>
+#include "defines.hpp"
+
+class AddressSpace {
+	bool bootromLoaded = true;
+	Byte bootrom[BOOTROM_SIZE] = {0};
+	std::ifstream game;
+
+public:
+	AddressSpace() {
+		// Initialize the memory to zero
+		memoryLayout = {};
+		std::memset(memoryLayout.memory, 0, sizeof(memoryLayout.memory));
+	}
+
+	// Nested union for the memory layout
+	union MemoryLayout {
+		Byte memory[0x10000];
+
+		struct {
+			Byte romBank1[ROM_BANK_SIZE]; // Mapped to 0x0000
+			Byte romBankSwitch[ROM_BANK_SIZE]; // Mapped to 0x4000
+			Byte vram[0x2000]; // Mapped to 0x8000
+			Byte externalRam[0x2000]; // Mapped to 0xA000
+			Byte memoryBank1[0x1000]; // Mapped to 0xC000
+			Byte memoryBank2[0x1000]; // Mapped to 0xD000
+			Byte echoRam[0x1E00]; // Mapped to 0xE000 (Echo RAM, mirrors 0xC000 to 0xDFFF)
+			Byte spriteAttributeTable[0xA0]; // Mapped to 0xFE00
+			Byte notUsable[0x60]; // Mapped to 0xFEA0
+			Byte io[0x80]; // Mapped to 0xFF00, 0xFF0F is interrupt flag
+			Byte specialRam[0x7F]; // Mapped to 0xFF80
+			Byte interuptEnableReg; // Mapped to 0xFFFF
+		};
+	} memoryLayout{};
+
+	void unmapBootrom();
+	void mapBootrom();
+	bool getBootromState() const;
+	void loadBootrom(const std::string& filename);
+	void loadGame(const std::string& filename);
+
+	void determineMBCInfo();
+	MBCType MBC = {};
+	uint32_t RomSize = 0;
+	uint32_t RomPages = 0;
+	uint32_t ExternalRamSize = 0;
+	uint32_t ExternalRamPages = 0;
+
+
+	//overload [] for echo ram and bootrom support
+	Byte operator[](const uint32_t address) const {
+		if (address >= 0xE000 && address < 0xFE00)
+			return memoryLayout.echoRam[address - 0x2000];
+		if (address < 0x0100 && bootromLoaded)
+			return bootrom[address];
+
+		return memoryLayout.memory[address];
+	}
+
+	Byte& operator[](const uint32_t address) {
+		if (address >= 0xE000 && address < 0xFE00)
+			return memoryLayout.echoRam[address - 0x2000];
+		if (address < 0x0100 && bootromLoaded)
+			return bootrom[address];
+
+		return memoryLayout.memory[address];
+	}
+};
+
+
+#endif //ADDRESSSPACE_HPP