diff --git a/patterns/ne.hexpat b/patterns/ne.hexpat
index 3cae5c2..6c825b1 100644
--- a/patterns/ne.hexpat
+++ b/patterns/ne.hexpat
@@ -1,3 +1,4 @@
+#pragma author gmestanley
 #pragma description Microsoft DOS NE executable
 #pragma MIME application/x-ms-ne-executable
 
diff --git a/patterns/nes.hexpat b/patterns/nes.hexpat
index 1fdce89..6292ada 100644
--- a/patterns/nes.hexpat
+++ b/patterns/nes.hexpat
@@ -2,87 +2,265 @@
 #pragma description Nintendo Entertainment System ROM (.nes)
 #pragma MIME application/x-nes-rom
 
-import std.mem;
 import std.string;
 
-bitfield iNES07Flags {
-	mirroringIsVertical : 1;
-	batterybackedPRGRAM : 1;
-	trainerOf512Bytes : 1;
-	ignoreMirroring : 1;
-	mapperLowerNybble : 4;
-	vsUnisystem : 1;
-	playchoice10 : 1;
-	nes2Format : 2 [[name("nes2.0Format")]];
-	mapperHigherNybble : 4;
-} [[name("iNES0.7Flags")]];
-
-bitfield Flags9 {
-	isPAL : 1;
-	padding : 7;
+bitfield Flags {
+    mirroringIsHorizontal : 1;
+    ignoreMirroring : 1;
+    batterybackedPRGRAM : 1;
+    trainerOf512Bytes : 1;
+    lowerMapperNybble : 4;
 };
 
-bitfield Flags10 {
-	tvSystem : 2;
-	padding : 2;
-	prgRAM : 1;
-	busConflicts : 1;
-	padding : 2;
+enum ConsoleType : u8 {
+    Regular,
+    VsSystem,
+    PlayChoice10,
+    ExtendedConsoleType
 };
 
-struct iNESFlags {
-	iNES07Flags ines07Flags [[name("ines0.7Flags")]];
-	if (!ines07Flags.nes2Format) {
-		u8 prgRAM8KBMultiplier;
-		Flags9 flags9;
-		Flags10 flags10;
-		restLength = 5;
-	}
-	else {
-		restLength = 9;
-	}
+fn consoleType(u8 bits) {
+    ConsoleType type = bits;
+    return type;
 };
 
-u8 restLength;
+fn nes2Format(u8 bits) {
+    return std::string::to_string(bits == 2) + " (" + std::string::to_string(bits) + ")";
+};
+
+bitfield iNESFlags7 {
+    consoleType : 2 [[format("consoleType")]];
+    nes2Format : 2 [[format("nes2Format"), name("nes2.0Format")]];
+    higherMapperNybble : 4;
+};
+
+bitfield iNESFlags9 {
+    tvSystem : 1 [[comment("0 = NTSC, 1 = PAL")]];
+    padding : 7;
+};
+
+fn formatDualTVSystem(u8 bits) {
+    match (bits) {
+    (0): return "NTSC";
+    (2): return "PAL";
+    (1 || 3): return "Dual Compatible";
+    }
+};
+
+bitfield iNESFlags10 {
+    dualTVSystem : 2 [[format("formatDualTVSystem")]];
+    padding : 2;
+    prgRAM : 1;
+    busConflicts : 1;
+};
+
+bitfield MapperExtra {
+    highestMapperNybble : 4;
+    submapper : 4;
+};
+
+bitfield ROMSize {
+    extraPRGROMSize : 4;
+    extraCHRROMSize : 4;
+};
+
+bitfield PRGRAMSize {
+    prgRAMShiftCount : 4;
+    eepromShiftCount : 4 [[comment("EEPROM = Non-volatile PRG RAM")]];
+};
+
+bitfield CHRRAMSize {
+    chrRAMSizeShiftCount : 4;
+    chrNVRAMSizeShiftCount : 4;
+};
+
+enum TimingList : u8 {
+    NTSC,
+    PAL,
+    MultiRegion,
+    Dendy
+};
+
+fn Timing(u8 value) {
+    TimingList type = value;
+    return type;
+};
+
+bitfield Timing {   
+    processorTiming : 2 [[format("Timing")]];
+    padding : 6;
+};
+
+bitfield VsSystemType {
+    vsPPUType : 4;
+    vsHardwareType: 4;
+};
+
+enum ExtendedConsoleType : ConsoleType {
+    DecimalModeFamiclone = 3,
+    PlugThrough,
+    VT01,
+    VT02,
+    VT03,
+    VT09,
+    VT32,
+    VT3xx,
+    UM6578,
+    FamicomNetworkSystem
+};
+
+fn formatExtendedConsoleType(u8 nybble) {
+    ExtendedConsoleType type = nybble;
+    return type;
+};
+
+bitfield ExtendedConsoleTypeByte {
+    type : 4 [[format("formatExtendedConsoleType")]];
+    padding : 4;
+};
+
+bitfield MiscellaneousROMs {
+    numberOfMiscellaneousROMs : 2;
+    padding : 6;
+};
+    
+bitfield DefaultExpansionDevice {
+    defaultExpansionDevice : 6;
+};
+
+struct NES2Attributes {
+    MapperExtra mapperExtra;
+    ROMSize romSize;
+    PRGRAMSize prgRAMSize;
+    CHRRAMSize chrRAMSize;
+    Timing timing;
+    if (parent.inesFlags7.consoleType == ConsoleType::VsSystem) {
+        VsSystemType vsSystemType;
+    }
+    else if (parent.inesFlags7.consoleType == ConsoleType::ExtendedConsoleType) {
+        ExtendedConsoleTypeByte ExtendedConsoleTypeByte;
+    }
+    else {
+        padding[1];
+    }
+    MiscellaneousROMs miscellaneousROMs;
+    DefaultExpansionDevice defaultExpansionDevice;
+};
+
+fn renderEOF(str string) {
+    return "\"NES<EOF>\"";
+};
 
 struct Header {
-	char identifier[4];
-	u8 prgROM16KBMultiplier;
-	u8 chrROM8KBMultiplier;
-	iNESFlags inesFlags;
-	char rest[restLength];
+    char identifier[4] [[format("renderEOF")]];
+    u8 prgROMSizeBy16KiBs;
+    u8 chrROMSizeBy8KiBs;
+    Flags flags;
+    if ($[0x07] & 12 != 4) {
+        iNESFlags7 inesFlags7;
+        if (inesFlags7.nes2Format)
+            NES2Attributes nes2Attributes;
+        else if ($[0x07] & 12 == 0 && !std::mem::read_unsigned($, 4)) {
+            u8 prgRAMSizeBy8KiBs;
+            iNESFlags9 inesFlags9;
+            iNESFlags10 inesFlags10;
+        }
+    }
 };
 
 Header header @ 0x00;
 
-enum EncodingType : u8 {
-	ASCII = 1
+u8 trainer[512*header.flags.trainerOf512Bytes] @ 0x10;
+
+enum CHRType : u8 {
+    CHRROM,
+    CHRRAM
 };
 
+fn chrType(u8 value) {
+    CHRType enumValue = value;
+    return enumValue;
+};
+
+fn chrSize(u8 value) {
+    u24 actualSize;
+    if (value == 4) actualSize = 262144;
+    else actualSize = 8192 * header.chrROMSizeBy8KiBs;
+    return std::string::to_string(value) + " (" + std::string::to_string(actualSize) + ")";
+};
+
+bitfield MemorySize {
+    prgROMSizeBy16KiBs : 4;
+    chrType : 1 [[format("chrType")]];
+    chrSize : 3 [[format("chrSize")]];
+};
+
+enum ArrangementList : u8 {
+    Horizontal,
+    Vertical
+};
+
+fn arrangement(u8 value) {
+    ArrangementList enumValue = value;
+    return enumValue;
+};
+
+enum MapperList : u8 {
+    NROM,
+    CNROM,
+    UNROM,
+    GNROM,
+    MMC
+};
+
+fn mapper(u8 value) {
+    MapperList enumValue = value;
+    return enumValue;
+};
+
+bitfield CartridgeType {
+    nametableArrangement : 1 [[format("arrangement")]];
+    mapper : 7 [[format("mapper")]];
+};
+
+enum EncodingType : u8 {
+    None,
+    ASCII,
+    JIS
+};
+
+fn titleLength(u8 value) { return value+1; };
+
 struct OfficialHeader {
-	char title[16] [[hex::spec_name("Title Registration Area")]];
-	u16 programChecksum;
-	u16 characterChecksum;
-	u8 memorySize [[hex::spec_name("Cartridge Memory Size")]];
-	u8 cartridgeType;
-	EncodingType encodingType [[hex::spec_name("Registration Character Type Distinction")]];
-	u8 titleLength [[hex::spec_name("Registration Characters Count")]];
-	u8 makerID [[hex::spec_name("Maker Code")]];
-	u8 complementaryChecksum;
+    char title[16] [[hex::spec_name("Title Registration Area")]];
+    u16 programChecksum;
+    u16 characterChecksum;
+    MemorySize memorySize [[hex::spec_name("Cartridge Memory Size")]];
+    CartridgeType cartridgeType;
+    EncodingType encodingType [[hex::spec_name("Registration Characters Type Distinction")]];
+    u8 titleLength [[hex::spec_name("Registration Characters Count"), transform("titleLength")]];
+    u8 licenseeID [[hex::spec_name("Maker Code")]];
+    u8 complementaryChecksum [[hex::spec_name("Checksum for characterChecksum~makerID")]];
 };
 
-union OfficialHeaderUnion {
-	u8 miscellaneousData[26];
-	OfficialHeader officialHeader;
+u24 calculatedPRGROMSize = 16384 * ((0x0100 * $[9] & 0x0F) * ($[7] & 12 == 8) + header.prgROMSizeBy16KiBs);
+
+fn hasOfficialHeader() {
+    u8 sum;
+    for (u8 i = 0, i < 8, i += 1) {
+        sum += $[(calculatedPRGROMSize - 14) + i];
+    }
+    return !sum;
 };
 
 struct PRGROM {
-	u8 data[16384*header.prgROM16KBMultiplier-32];
-	OfficialHeaderUnion officialHeaderUnion;
-	u16 nmi;
-	u16 entryPoint;
-	u16 externalIRQ;
+    u8 data[calculatedPRGROMSize - 26 * hasOfficialHeader() - 6];
+    if (hasOfficialHeader())
+        OfficialHeader officialHeader;
+    u16 nmi;
+    u16 resetVector [[comment("Entry Point")]];
+    u16 externalIRQ;
 };
 
-PRGROM prgROM @ sizeof(header);
-u8 chrROM[8192*header.chrROM8KBMultiplier] @ sizeof(header)+sizeof(prgROM);
\ No newline at end of file
+PRGROM prgROM @ 0x10 + sizeof(trainer);
+u8 chrROM[8192 * ((0x0100 * $[9] >> 4) * ($[7] & 12 == 8) + header.chrROMSizeBy8KiBs)] @ addressof(prgROM) + 16384 * header.prgROMSizeBy16KiBs;