ares64 core: Add basic support for the SC64 SD card interface (#4438)

* ares64 core: Add basic support for the SC64 SD card interface

Co-authored-by: YoshiRulz <[email protected]>

Author: Thar0

Assets/dll/ares64_interpreter.wbx.zst

@@ -1,5 +1,5 @@
+using System.Collections.Generic;
 using System.IO;
-using System.Linq;
 
 using BizHawk.Common;
 using BizHawk.Emulation.Common;
@@ -13,6 +13,8 @@ public partial class Ares64 : WaterboxCore, IRegionable
 	{
 		private readonly LibAres64 _core;
 		private readonly Ares64Disassembler _disassembler;
+		private const int MameFormatSize = 0x435B0C0;
+		private const int NddFormatSize = 0x3DEC800;
 
 		[CoreConstructor(VSystemID.Raw.N64)]
 		public Ares64(CoreLoadParameters<Ares64Settings, Ares64SyncSettings> lp)
@@ -64,18 +66,40 @@ static bool IsGBRom(byte[] rom)
 				return ninLogoSha1 == SHA1Checksum.ComputeDigestHex(new ReadOnlySpan<byte>(rom).Slice(0x104, 48));
 			}
 
+			List<byte[]> gbRoms = [ ];
+			byte[] rom = null;
+			byte[] disk = null;
+			byte[] error = null;
+			byte[] sdCard = null;
+
 			// TODO: this is normally handled frontend side
 			// except XML files don't go through RomGame
 			// (probably should, but needs refactoring)
-			foreach (var r in lp.Roms) _ = N64RomByteswapper.ToZ64Native(r.RomData); // no-op if N64 magic bytes not present
+			foreach (var r in lp.Roms)
+			{
+				_ = N64RomByteswapper.ToZ64Native(r.RomData); // no-op if N64 magic bytes not present
 
-			var gbRoms = lp.Roms.FindAll(r => IsGBRom(r.FileData)).Select(r => r.FileData).ToArray();
-			var rom = lp.Roms.Find(r => !gbRoms.Contains(r.FileData) && (char)r.RomData[0x3B] is 'N' or 'C')?.RomData;
-			var (disk, error) = TransformDisk(lp.Roms.Find(r => !gbRoms.Contains(r.FileData) && r.RomData != rom)?.FileData);
+				if (r.FileData.Length is MameFormatSize or NddFormatSize)
+				{
+					(disk, error) = TransformDisk(r.FileData);
+				}
+				else if (IsGBRom(r.FileData))
+				{
+					gbRoms.Add(r.FileData);
+				}
+				else if ((char) r.RomData[0x3B] is 'N' or 'C')
+				{
+					rom = r.RomData;
+				}
+				else if (r.FileData.AsSpan(start: 0x1FE) is [ 0x55, 0xAA, .. ])
+				{
+					sdCard = r.FileData;
+				}
+			}
 
 			if (rom is null && disk is null)
 			{
-				if (gbRoms.Length == 0 && lp.Roms.Count == 1) // let's just assume it's an N64 ROM then
+				if (gbRoms.Count == 0 && lp.Roms.Count == 1) // let's just assume it's an N64 ROM then
 				{
 					rom = lp.Roms[0].RomData;
 				}
@@ -116,7 +140,7 @@ static bool IsGBRom(byte[] rom)
 			}
 
 			byte[] GetGBRomOrNull(int n)
-				=> n < gbRoms.Length ? gbRoms[n] : null;
+				=> n < gbRoms.Count ? gbRoms[n] : null;
 
 			unsafe
 			{
@@ -129,7 +153,8 @@ byte[] GetGBRomOrNull(int n)
 					gb1RomPtr = GetGBRomOrNull(0),
 					gb2RomPtr = GetGBRomOrNull(1),
 					gb3RomPtr = GetGBRomOrNull(2),
-					gb4RomPtr = GetGBRomOrNull(3))
+					gb4RomPtr = GetGBRomOrNull(3),
+					sdPtr = sdCard)
 				{
 					var loadData = new LibAres64.LoadData
 					{
@@ -151,6 +176,8 @@ byte[] GetGBRomOrNull(int n)
 						Gb3RomLen = GetGBRomOrNull(2)?.Length ?? 0,
 						Gb4RomData = (IntPtr)gb4RomPtr,
 						Gb4RomLen = GetGBRomOrNull(3)?.Length ?? 0,
+						SdData = (IntPtr)sdPtr,
+						SdLen = sdCard?.Length ?? 0,
 					};
 					if (!_core.Init(ref loadData, ControllerSettings, pal, GetRtcTime(!DeterministicEmulation)))
 					{
@@ -352,7 +379,7 @@ static bool RepeatCheck(ReadOnlySpan<byte> slice, int size, int repeat)
 			{
 				for (int i = 0; i < 4; i++)
 				{
-					var systemBlock = disk.Length == 0x3DEC800 ? (systemBlocks[i] + 2) ^ 1 : (systemBlocks[i] + 2);
+					var systemBlock = disk.Length == NddFormatSize ? (systemBlocks[i] + 2) ^ 1 : (systemBlocks[i] + 2);
 					var systemOffset = systemBlock * 0x4D08;
 					ret[systemBlocks[i] + 2] = 1;
 					if (disk[systemOffset + 0x00] != 0x00) continue;
@@ -414,10 +441,10 @@ private static (byte[] Disk, byte[] Error) TransformDisk(byte[] disk)
 			if (disk is null) return default;
 
 			// already in mame format
-			if (disk.Length == 0x435B0C0) return (disk, CreateErrorTable(disk));
+			if (disk.Length == MameFormatSize) return (disk, CreateErrorTable(disk));
 
 			// ndd is always 0x3DEC800 bytes apparently?
-			if (disk.Length != 0x3DEC800) return default;
+			if (disk.Length != NddFormatSize) return default;
 
 			// need the error table for this
 			var errorTable = CreateErrorTable(disk);
@@ -453,7 +480,7 @@ private static (byte[] Disk, byte[] Error) TransformDisk(byte[] disk)
 			var dataFormat = new ReadOnlySpan<byte>(disk, systemOffset, 0xE8);
 
 			var diskIndex = 0;
-			var ret = new byte[0x435B0C0];
+			var ret = new byte[MameFormatSize];
 
 			var type = dataFormat[5] & 0xF;
 			var vzone = 0;

Assets/dll/ares64_recompiler.wbx.zst

@@ -106,6 +106,8 @@ public struct LoadData
 			public long Gb3RomLen;
 			public IntPtr Gb4RomData;
 			public long Gb4RomLen;
+			public IntPtr SdData;
+			public long SdLen;
 		}
 
 		[BizImport(CC)]

src/BizHawk.Emulation.Cores/Consoles/Nintendo/Ares64/Ares64.cs

@@ -147,6 +147,7 @@ static array_view<u8>* diskErrorData = nullptr;
 static array_view<u8>* saveData = nullptr;
 static array_view<u8>* rtcData = nullptr;
 static array_view<u8>* gbRomData[4] = { nullptr, nullptr, nullptr, nullptr, };
+static array_view<u8>* sdData = nullptr;
 
 typedef enum
 {
@@ -417,6 +418,8 @@ typedef struct
 	u8* DiskErrorData;
 	u64 DiskErrorLen;
 	GbRom GbRoms[4];
+	u8* SdData;
+	u64 SdLen;
 } LoadData;
 
 static bool LoadRom(LoadData* loadData, bool isPal)
@@ -560,6 +563,16 @@ ECL_EXPORT bool Init(LoadData* loadData, ControllerType* controllers, bool isPal
 		platform->bizpak->append(name, *iplData);
 	}
 
+	if (loadData->SdData)
+	{
+		name = "sd.raw";
+		len = loadData->SdLen;
+		data = new u8[len];
+		memcpy(data, loadData->SdData, len);
+		sdData = new array_view<u8>(data, len);
+		platform->bizpak->append(name, *sdData);
+	}
+
 	string region = isPal ? "PAL" : "NTSC";
 	platform->bizpak->setAttribute("region", region);
 

src/BizHawk.Emulation.Cores/Consoles/Nintendo/Ares64/LibAres64.cs

@@ -7,6 +7,7 @@ Cartridge& cartridge = cartridgeSlot.cartridge;
 #include "flash.cpp"
 #include "rtc.cpp"
 #include "joybus.cpp"
+#include "sc64.cpp"
 #include "isviewer.cpp"
 #include "debugger.cpp"
 #include "serialization.cpp"
@@ -54,6 +55,14 @@ auto Cartridge::connect() -> void {
     isviewer.tracer->setTerminal(true);
   }
 
+  if(auto fp = pak->read("sd.raw")) {
+    sc64.sd.allocate(fp->size());
+    sc64.sd.load(fp);
+    sc64.buffer.allocate(0x2000);
+    sc64.buffer.fill();
+    sc64.enabled = true;
+  }
+
   debugger.load(node);
 
   power(false);
@@ -69,6 +78,10 @@ auto Cartridge::disconnect() -> void {
   flash.reset();
   isviewer.ram.reset();
   pak.reset();
+  if(sc64.enabled) {
+    sc64.sd.reset();
+    sc64.buffer.reset();
+  }
   node.reset();
 }
 
@@ -88,6 +101,12 @@ auto Cartridge::save() -> void {
   }
 
   rtc.save();
+
+  if(sc64.enabled) {
+    if(auto fp = system.pak->write("sd.raw")) {
+      sc64.sd.save(fp);
+    }
+  }
 }
 
 auto Cartridge::power(bool reset) -> void {

waterbox/ares64/BizInterface.cpp

@@ -4,6 +4,41 @@ struct Cartridge {
   Memory::Readable16 rom;
   Memory::Writable16 ram;
   Memory::Writable16 eeprom;
+  struct SC64 {
+    static constexpr u32 SDSectorWords = 512/4;
+
+    n1 enabled = false;
+    Memory::Writable sd;
+    Memory::Writable buffer;
+
+    n2 lockState = 0;
+    n1 busy = 0;
+    n1 error = 0;
+    u32 data0 = 0;
+    u32 data1 = 0;
+
+    n1 sdIsInit = 0;
+    u32 sdAddr = 0;
+
+    auto regReadWord(u32 address) -> u64;
+    auto regWriteWord(u32 address, u64 data_) -> void;
+
+    auto serialize(serializer& s) -> void;
+
+    template<u32 Size>
+    auto regRead(u32 address) -> u64 {
+      if constexpr(Size == Word) return regReadWord(address);
+      debug(unimplemented, "[SC64] Register read of size other than Word");
+      return 0; //Other sizes unimplemented
+    }
+
+    template<u32 Size>
+    auto regWrite(u32 address, u64 data) -> void {
+      if constexpr(Size == Word) return regWriteWord(address, data);
+      debug(unimplemented, "[SC64] Register write of size other than Word");
+      return; //Other sizes unimplemented
+    }
+  } sc64;
   struct Flash : Memory::Writable {
     template<u32 Size>
     auto read(u32 address) -> u64 {

waterbox/ares64/ares/ares/n64/cartridge/cartridge.cpp

@@ -0,0 +1,143 @@
+auto Cartridge::SC64::regReadWord(u32 address) -> u64 {
+  n32 data;
+  data.bit(0,31) = (address << 16) | (address & 0xFFFF);
+  address = (address & 0x1F) >> 2;
+
+  if (lockState != 2) {
+    return u64(data);
+  }
+
+  if(address == 0) {
+    //SCR, command execution and status
+    //Mostly unimplemented
+    data.bit(31) = busy;
+    data.bit(30) = error;
+  }
+
+  if(address == 1) {
+    //DATA0, command arg/result 0
+    data.bit(0,31) = data0;
+  }
+
+  if(address == 2) {
+    //DATA1, command arg/result 1
+    data.bit(0,31) = data1;
+  }
+
+  if(address == 3) {
+    //IDENTIFIER, flashcart identifier
+    //Read-only
+    data.bit(0,31) = 0x53'43'76'32; /* SCv2 */
+  }
+
+  if(address == 4) {
+    //KEY
+    //Write-only
+  }
+
+  if(address == 5) {
+    //IRQ
+    //Unimplemented
+  }
+
+  if(address == 6) {
+    //AUX
+    //Unimplemented
+  }
+
+  return u64(data);
+}
+
+auto Cartridge::SC64::regWriteWord(u32 address, u64 data_) -> void {
+  address = (address & 0x1F) >> 2;
+  n32 data = data_;
+
+  if(address == 0 && lockState == 2) {
+    //SCR, command execution and status
+    //Writes initiate a command
+    u8 cmd = data.bit(0,7);
+
+    switch (cmd) {
+      case 'i': //SD Operation
+        if(data1 == 1) //SD Init
+          sdIsInit = true;
+        break;
+
+      case 'I': //SD Sector Set
+        sdAddr = data0 * SC64::SDSectorWords * 4;
+        break;
+
+      case 's': //SD Read Sectors
+        if(sdIsInit) {
+          u32 piAddress = data0;
+          u32 numSectors = data1;
+          u32 numWords = numSectors * SC64::SDSectorWords;
+          //Note: Only data buffer is supported here but real SC64 is more flexible
+          for(auto offset : range(numWords))
+            buffer.write<Word>(piAddress + offset * 4, sd.read<Word>(sdAddr + offset * 4));
+        }
+        break;
+
+      case 'S': //SD Write Sectors
+        if(sdIsInit) {
+          u32 piAddress = data0;
+          u32 numSectors = data1;
+          u32 numWords = numSectors * SC64::SDSectorWords;
+          //Note: Only data buffer is supported here but real SC64 is more flexible
+          for(auto offset : range(numWords))
+            sd.write<Word>(sdAddr + offset * 4, buffer.read<Word>(piAddress + offset * 4));
+        }
+        break;
+
+      default: break; //Unrecongized/Unimplemented
+    }
+  }
+
+  if(address == 1 && lockState == 2) {
+    //DATA0, command arg/result 0
+    data0 = data.bit(0,31);
+  }
+
+  if(address == 2 && lockState == 2) {
+    //DATA1, command arg/result 1
+    data1 = data.bit(0,31);
+  }
+
+  if(address == 3 && lockState == 2) {
+    //IDENTIFIER, flashcart identifier
+    //Read-only
+  }
+
+  if(address == 4) {
+    //KEY
+    if(data.bit(0,31) == 0x00000000 || data.bit(0,31) == 0xFFFFFFFF)
+      lockState = 0;
+    else if(data.bit(0,31) == 0x5F554E4C && lockState == 0)
+      lockState = 1;
+    else if(data.bit(0,31) == 0x4F434B5F && lockState == 1)
+      lockState = 2;
+  }
+
+  if(address == 5 && lockState == 2) {
+    //IRQ
+    //Unimplemented
+  }
+
+  if(address == 6 && lockState == 2) {
+    //AUX
+    //Unimplemented
+  }
+}
+
+auto Cartridge::SC64::serialize(serializer& s) -> void {
+  s(enabled);
+  s(sd);
+  s(buffer);
+  s(lockState);
+  s(busy);
+  s(error);
+  s(data0);
+  s(data1);
+  s(sdIsInit);
+  s(sdAddr);
+}