Implement IDebuggable for the new bsnes core

src/BizHawk.Emulation.Cores/Consoles/Nintendo/BSNES/BsnesApi.cs

@@ -59,6 +59,13 @@ namespace BizHawk.Emulation.Cores.Nintendo.BSNES
 		public abstract void snes_load_cartridge_normal(string baseRomPath, byte[] romData, int romSize);
 		[BizImport(CallingConvention.Cdecl)]
 		public abstract void snes_load_cartridge_super_gameboy(string baseRomPath, byte[] romData, byte[] sgbRomData, ulong mergedRomSizes);
+
+		[BizImport(CallingConvention.Cdecl)]
+		public abstract void snes_get_cpu_registers(ref BsnesApi.CpuRegisters registers);
+		[BizImport(CallingConvention.Cdecl)]
+		public abstract void snes_set_cpu_register(string register, uint value);
+		[BizImport(CallingConvention.Cdecl)]
+		public abstract bool snes_cpu_step();
 	}
 
 	public unsafe partial class BsnesApi : IDisposable, IMonitor, IStatable
@@ -144,6 +151,29 @@ namespace BizHawk.Emulation.Cores.Nintendo.BSNES
 		public delegate string snes_path_request_t(int slot, string hint, bool required);
 		public delegate void snes_trace_t(string disassembly, string register_info);
 
+		[StructLayout(LayoutKind.Sequential)]
+		public struct CpuRegisters
+		{
+			public uint pc;
+			public ushort a, x, y, z, s, d;
+			public byte b, p, mdr;
+			public bool e;
+			public ushort v, h;
+		}
+
+		[Flags]
+		public enum RegisterFlags : byte
+		{
+			C = 1,
+			Z = 2,
+			I = 4,
+			D = 8,
+			X = 16,
+			M = 32,
+			V = 64,
+			N = 128,
+		}
+
 		[StructLayout(LayoutKind.Sequential)]
 		public struct LayerEnables
 		{
@@ -165,17 +195,14 @@ namespace BizHawk.Emulation.Cores.Nintendo.BSNES
 			public snes_path_request_t pathRequestCb;
 			public snes_trace_t snesTraceCb;
 
-			private static List<FieldInfo> FieldsInOrder = null;
+			private static List<FieldInfo> FieldsInOrder;
 
 			public IEnumerable<Delegate> AllDelegatesInMemoryOrder()
 			{
-				if (FieldsInOrder == null)
+				FieldsInOrder ??= GetType()
-				{
+					.GetFields()
-					FieldsInOrder = GetType()
+					.OrderBy(BizInvokerUtilities.ComputeFieldOffset)
-						.GetFields()
+					.ToList();
-						.OrderBy(fi => BizInvokerUtilities.ComputeFieldOffset(fi))
-						.ToList();
-				}
 				return FieldsInOrder
 					.Select(f => (Delegate)f.GetValue(this));
 			}

src/BizHawk.Emulation.Cores/Consoles/Nintendo/BSNES/BsnesCore.IDebuggable.cs

@@ -0,0 +1,159 @@
+using System;
+using System.Collections.Generic;
+
+using BizHawk.Emulation.Common;
+using static BizHawk.Emulation.Cores.Nintendo.BSNES.BsnesApi;
+
+namespace BizHawk.Emulation.Cores.Nintendo.BSNES
+{
+	public partial class BsnesCore : IDebuggable
+	{
+		public IDictionary<string, RegisterValue> GetCpuFlagsAndRegisters()
+		{
+			CpuRegisters registers = default;
+			Api.core.snes_get_cpu_registers(ref registers);
+
+			var flags = (RegisterFlags) registers.p;
+
+			bool fc = (flags & RegisterFlags.C) != 0;
+			bool fz = (flags & RegisterFlags.Z) != 0;
+			bool fi = (flags & RegisterFlags.I) != 0;
+			bool fd = (flags & RegisterFlags.D) != 0;
+			bool fx = (flags & RegisterFlags.X) != 0;
+			bool fm = (flags & RegisterFlags.M) != 0;
+			bool fv = (flags & RegisterFlags.V) != 0;
+			bool fn = (flags & RegisterFlags.N) != 0;
+
+			return new Dictionary<string, RegisterValue>
+			{
+				["PC"] = registers.pc,
+				["A"] = registers.a,
+				["X"] = registers.x,
+				["Y"] = registers.y,
+				["Z"] = registers.z,
+				["S"] = registers.s,
+				["D"] = registers.d,
+				["B"] = registers.b,
+				["P"] = registers.p,
+				["E"] = registers.e,
+				["Flag C"] = fc,
+				["Flag Z"] = fz,
+				["Flag I"] = fi,
+				["Flag D"] = fd,
+				["Flag X"] = fx,
+				["Flag M"] = fm,
+				["Flag V"] = fv,
+				["Flag N"] = fn,
+				["MDR"] = registers.mdr,
+				["V"] = registers.v,
+				["H"] = registers.h
+			};
+		}
+
+		public void SetCpuRegister(string register, int value)
+		{
+			Api.core.snes_set_cpu_register(register, (uint) value);
+		}
+
+		public IMemoryCallbackSystem MemoryCallbacks { get; } = new MemoryCallbackSystem(null);
+
+		public bool CanStep(StepType type)
+		{
+			switch (type)
+			{
+				case StepType.Into:
+				case StepType.Over:
+				case StepType.Out:
+					return true;
+				default:
+					return false;
+			}
+		}
+
+		public void Step(StepType type)
+		{
+			_framePassed = false;
+			switch (type)
+			{
+				case StepType.Into:
+					StepInto();
+					break;
+				case StepType.Over:
+					StepOver();
+					break;
+				case StepType.Out:
+					StepOut();
+					break;
+				default:
+					throw new NotImplementedException();
+			}
+		}
+
+		public long TotalExecutedCycles { get; private set; }
+
+		private void StepInto()
+		{
+			_framePassed = Api.core.snes_cpu_step();
+			TotalExecutedCycles++;
+			if (_framePassed)
+			{
+				Frame++;
+				if (IsLagFrame) LagCount++;
+			}
+		}
+
+		private void StepOver()
+		{
+			CpuRegisters registers = default;
+			Api.core.snes_get_cpu_registers(ref registers);
+			byte opcode = Api.core.snes_bus_read(registers.pc);
+
+			if (IsSubroutineCall(opcode))
+			{
+				uint destination = registers.pc + JumpInstructionLength(opcode);
+				do
+				{
+					StepInto();
+					Api.core.snes_get_cpu_registers(ref registers);
+				} while (registers.pc != destination && !_framePassed);
+			}
+			else
+			{
+				StepInto();
+			}
+		}
+
+		private void StepOut()
+		{
+			CpuRegisters registers = default;
+			Api.core.snes_get_cpu_registers(ref registers);
+			byte opcode = Api.core.snes_bus_read(registers.pc);
+
+			while (!IsReturn(opcode) && !_framePassed)
+			{
+				StepOver();
+				Api.core.snes_get_cpu_registers(ref registers);
+				opcode = Api.core.snes_bus_read(registers.pc);
+			}
+
+			if (!_framePassed)
+			{
+				StepInto();
+			}
+		}
+
+		private bool _framePassed;
+		private static bool IsSubroutineCall(byte opcode) => opcode is 0x20 or 0x22 or 0xfc;
+		private static bool IsReturn(byte opcode) => opcode is 0x60 or 0x6b;
+
+		private static uint JumpInstructionLength(byte opcode)
+		{
+			return opcode switch
+			{
+				0x20 or 0xfc => 3,
+				0x22 => 4,
+				_ => throw new ArgumentOutOfRangeException()
+			};
+		}
+	}
+}

src/BizHawk.Emulation.Cores/Consoles/Nintendo/BSNES/BsnesCore.IEmulator.cs

@@ -53,8 +53,8 @@ namespace BizHawk.Emulation.Cores.Nintendo.BSNES
 			Api.core.snes_set_audio_enabled(renderSound);
 
 			// run the core for one frame
-			Frame++;
 			Api.core.snes_run();
+			Frame++;
 
 			if (IsLagFrame)
 			{

src/BizHawk.Emulation.Cores/Consoles/Nintendo/BSNES/BsnesCore.IMemoryDomains.cs

@@ -1,6 +1,5 @@
 using System;
 using System.Collections.Generic;
-using BizHawk.Common;
 using BizHawk.Emulation.Common;
 
 namespace BizHawk.Emulation.Cores.Nintendo.BSNES

src/BizHawk.Emulation.Cores/Consoles/Nintendo/BSNES/BsnesCore.cs

@@ -13,7 +13,7 @@ namespace BizHawk.Emulation.Cores.Nintendo.BSNES
 {
 	[PortedCore(CoreNames.Bsnes115, "bsnes team", "v115+", "https://bsnes.dev", isReleased: false)]
 	[ServiceNotApplicable(new[] { typeof(IDriveLight) })]
-	public unsafe partial class BsnesCore : IEmulator, IVideoProvider, ISaveRam, IStatable, IInputPollable, IRegionable, ISettable<BsnesCore.SnesSettings, BsnesCore.SnesSyncSettings>
+	public unsafe partial class BsnesCore : IEmulator, IDebuggable, IVideoProvider, ISaveRam, IStatable, IInputPollable, IRegionable, ISettable<BsnesCore.SnesSettings, BsnesCore.SnesSyncSettings>
 	{
 		private BsnesApi.SNES_REGION _region;
 

waterbox/bsnescore/bsnes/sfc/cpu/cpu.cpp

@@ -28,6 +28,7 @@ auto CPU::Enter() -> void {
   while(true) {
     scheduler.synchronize();
     cpu.main();
+    if (scheduler.StepOnce) scheduler.leave(Scheduler::Event::Desynchronized);
   }
 }
 

waterbox/bsnescore/bsnes/sfc/sfc.hpp

@@ -34,6 +34,7 @@ namespace SuperFamicom {
     cothread_t host = nullptr;
     cothread_t active = nullptr;
     bool desynchronized = false;
+    bool StepOnce = false;
 
     auto enter() -> void {
       host = co_active();

waterbox/bsnescore/bsnes/target-bsnescore/bsnescore.cpp

@@ -361,3 +361,55 @@ EXPORT void snes_bus_write(unsigned addr, uint8_t value)
 {
     bus.write(addr, value);
 }
+
+EXPORT void snes_get_cpu_registers(SnesRegisters* registers)
+{
+    registers->pc = SuperFamicom::cpu.r.pc.d;
+    registers->a = SuperFamicom::cpu.r.a.w;
+    registers->x = SuperFamicom::cpu.r.x.w;
+    registers->y = SuperFamicom::cpu.r.y.w;
+    registers->z = SuperFamicom::cpu.r.z.w;
+    registers->s = SuperFamicom::cpu.r.s.w;
+    registers->d = SuperFamicom::cpu.r.d.w;
+
+    registers->b = SuperFamicom::cpu.r.b;
+    registers->p = SuperFamicom::cpu.r.p;
+    registers->mdr = SuperFamicom::cpu.r.mdr;
+    registers->e = SuperFamicom::cpu.r.e;
+
+    registers->v = SuperFamicom::cpu.vcounter();
+    registers->h = SuperFamicom::cpu.hdot();
+}
+
+EXPORT void snes_set_cpu_register(char* _register, uint32_t value)
+{
+    string register = _register;
+    if (register == "PC") SuperFamicom::cpu.r.pc = value;
+    if (register == "A") SuperFamicom::cpu.r.a = value;
+    if (register == "X") SuperFamicom::cpu.r.x = value;
+    if (register == "Y") SuperFamicom::cpu.r.y = value;
+    if (register == "Z") SuperFamicom::cpu.r.z = value;
+    if (register == "S") SuperFamicom::cpu.r.s = value;
+    if (register == "D") SuperFamicom::cpu.r.d = value;
+    if (register == "B") SuperFamicom::cpu.r.b = value;
+    if (register == "P") SuperFamicom::cpu.r.p = value;
+    if (register == "E") SuperFamicom::cpu.r.e = value;
+    if (register == "MDR") SuperFamicom::cpu.r.mdr = value;
+
+    if (register == "FLAG C") SuperFamicom::cpu.r.p.c = value;
+    if (register == "FLAG Z") SuperFamicom::cpu.r.p.z = value;
+    if (register == "FLAG I") SuperFamicom::cpu.r.p.i = value;
+    if (register == "FLAG D") SuperFamicom::cpu.r.p.d = value;
+    if (register == "FLAG X") SuperFamicom::cpu.r.p.x = value;
+    if (register == "FLAG M") SuperFamicom::cpu.r.p.m = value;
+    if (register == "FLAG V") SuperFamicom::cpu.r.p.v = value;
+    if (register == "FLAG N") SuperFamicom::cpu.r.p.n = value;
+}
+
+EXPORT bool snes_cpu_step()
+{
+    scheduler.StepOnce = true;
+    emulator->run();
+    scheduler.StepOnce = false;
+    return scheduler.event == Scheduler::Event::Frame;
+}

waterbox/bsnescore/bsnes/target-bsnescore/bsnescore.hpp

@@ -33,6 +33,15 @@ struct LayerEnables
     bool Obj_Prio0, Obj_Prio1, Obj_Prio2, Obj_Prio3;
 };
 
+struct SnesRegisters
+{
+    uint32_t pc;
+    uint16_t a, x, y, z, s, d;
+    uint8_t b, p, mdr;
+    bool e;
+    uint16_t v, h;
+};
+
 
 // below code unused; would be useful for the graphics debugger
 //$2105