patterns: More accurate variable declarations on nes.hexpat, add n64, gen, and gbx.hexpat (#477)

* Add n64, gen, and gbx.hexpat

* Add n64, gbx, and gen.hexpat to README.md

* Remove leftover string import from n64.hexpat

* More accurate variable declarations on nes.hexpat

* Add source to gbx.hexpat

* Add accidentally missing curly brace in nes.hexpat

patterns/gen.hexpat

@@ -0,0 +1,137 @@
+#pragma author gmestanley
+#pragma description Sega Genesis/MegaDrive header
+#pragma source plutiedev.com/rom-header wiki.neogeodev.org/index.php?title=68k_vector_table
+
+#pragma endian big
+
+import std.string;
+
+struct M68000Vectors {
+	u32 stackPointerReset;
+	u32 programCounterReset [[comment("Entry Point")]];
+	u32 busError;
+	u32 addressError;
+	u32 illegalInstruction;
+	u32 divisionByZero;
+	u32 chkInstruction;
+	u32 trapVInstruction;
+	u32 privilegeViolation;
+	u32 trace;
+	u32 lineAInstruction;
+	u32 lineFInstruction;
+	padding[12];
+	u32 uninitializedInterruptVector;
+	padding[32];
+	u32 spuriousInterrupt;
+	u32 interruptAutovectors[7];
+	u32 traps[16];
+};
+
+M68000Vectors vectors @ 0x00;
+
+struct Info {
+	char softwareType[2];
+	char space;
+	char serialNumber[8];
+	char dash;
+	char revision[2];
+};
+
+enum DeviceType : char {
+	NotFilled = ' ',
+	Button3Controller = 'J',
+	Button6Controller = '6',
+	MasterSystemController = '0',
+	AnalogJoystick = 'A',
+	Multitap = '4',
+	Lightgun = 'G',
+	Activator = 'L',
+	Mouse = 'M',
+	Trackball = 'B',
+	Mouse = 'T',
+	Trackball = 'V',
+	Keyboard = 'K',
+	RS232 = 'R',
+	Printer = 'P',
+	CDROM = 'C',
+	FloppyDrive = 'F',
+	Download = 'D'
+};
+
+bitfield RAMType {
+	addresses : 1;
+	padding : 3;
+	bits : 2;
+	saves : 1;
+	sig : 1;
+};
+
+enum MemoryType : char {
+	RAM = ' ',
+	EEPROM = '@'
+};
+
+struct ExtraMemory {
+	char signature[2];
+	RAMType ramType;
+	MemoryType memoryType;
+	u32 startAddress;
+	u32 endAddress;
+};
+
+fn renderMicrophoneType(str value) {
+	match(value) {
+		("00"): value = "NoMicJapanOnly";
+		("10"): value = "MicJapanOnly";
+		("20"): value = "NoMicOverseasOnly";
+		("30"): value = "MicOverseasOnly";
+		("40"): value = "NoMic";
+		("50"): value = "Mic";
+		("60"): value = "NoMicJapan";
+		("70"): value = "NoMicOverseas";
+	}
+};
+
+struct ModemSupport {
+	char signature[2];
+	char publisher[4];
+	char gameNumber[2];
+	char comma;
+	char version;
+	char microphone[2] [[format("renderMicrophoneType")]];
+};
+
+enum RegionType : char {
+	None = ' ',
+	Japan = 'J',
+	Americas = 'U',
+	Europe = 'E'
+};
+
+fn formatTerminatedString(str string) {
+	u8 index;
+	while (index < std::string::length(string)) {
+		if (std::mem::read_string($+index, 2) == "  ")
+			break;
+		index += 1;
+	}
+	return "\"" + std::string::substr(string, 0, index) + "\"";
+};
+
+struct Header {
+	char systemType[16] [[format("formatTerminatedString")]];
+	char copyright[16] [[format("formatTerminatedString")]];
+	char domesticTitle[48] [[format("formatTerminatedString")]];
+	char overseasTitle[48] [[format("formatTerminatedString")]];
+	Info info;
+	u16 checksum;
+	DeviceType deviceType[16];
+	u32 romAddressRange[2];
+	u32 ramAddressRange[2];
+	if ($[$] == 'R') ExtraMemory extraMemory; else padding[12];
+	if ($[$] == 'M') ModemSupport modemSupport; else padding[12];
+	padding[40];
+	RegionType regions[3];
+};
+
+Header header @ 0x100;