gba: support register reading. shows current mode's r0..r15, cpsr, spsr. at the moment, none of the other out of context banked regs are shown, which may or may not be a good idea.

BizHawk.Emulation/Consoles/Nintendo/GBA/LibMeteor.cs

@@ -261,5 +261,33 @@ namespace BizHawk.Emulation.Consoles.Nintendo.GBA
 		/// <param name="scanline">0-227, 160 occurring first in a frame</param>
 		[DllImport("libmeteor.dll", CallingConvention = CallingConvention.Cdecl)]
 		public static extern void libmeteor_setscanlinecallback(ScanlineCallback callback, int scanline);
+
+		/// <summary>
+		/// get current cpu regs
+		/// </summary>
+		/// <param name="dest">length 18 please</param>
+		public static extern void libmeteor_getregs(int[] dest);
+
+		public static readonly string[] regnames = new string[]
+		{
+			"r0",
+			"r1",
+			"r2",
+			"r3",
+			"r4",
+			"r5",
+			"r6",
+			"r7",
+			"r8",
+			"r9",
+			"r10",
+			"r11",
+			"r12",
+			"r13",
+			"r14",
+			"r15",
+			"cpsr",
+			"spsr"
+		};
 	}
 }

BizHawk.Emulation/Consoles/Nintendo/GBA/Meteor.cs

@@ -12,7 +12,12 @@ namespace BizHawk.Emulation.Consoles.Nintendo.GBA
 	{
 		public List<KeyValuePair<string, int>> GetCpuFlagsAndRegisters()
 		{
-			throw new NotImplementedException();
+			var ret = new List<KeyValuePair<string, int>>();
+			int[] data = new int[LibMeteor.regnames.Length];
+			LibMeteor.libmeteor_getregs(data);
+			for (int i = 0; i < data.Length; i++)
+				ret.Add(new KeyValuePair<string, int>(LibMeteor.regnames[i], data[i]));
+			return ret;
 		}
 
 		public static readonly ControllerDefinition GBAController =

libmeteor/cinterface.cpp

@@ -235,3 +235,12 @@ void scanlinecallback_bizhawk()
 	if (slcallback)
 		slcallback();
 }
+
+EXPORT void libmeteor_getregs(int *dest)
+{
+	AMeteor::_cpu.UpdateCpsr();	
+	for (int i = 0; i < 16; i++)
+		dest[i] = AMeteor::_cpu.Reg(i);
+	dest[16] = AMeteor::_cpu.Cpsr().dw;
+	dest[17] = AMeteor::_cpu.Spsr().dw;
+}