GBA: Ignore invalid opcodes used by the Wii U VC emulator (fixes #471)

CHANGES

@@ -70,6 +70,7 @@ Misc:
  - Qt: Rename "Resample video" option to "Bilinear filtering"
  - GBA Video: Optimize when BLD* registers are written frequently
  - Core: Cores can now have multiple sets of callbacks
+ - GBA: Ignore invalid opcodes used by the Wii U VC emulator
 
 0.5.2: (2016-12-31)
 Bugfixes:

src/gba/gba.c

@@ -577,6 +577,10 @@ void GBAIllegal(struct ARMCore* cpu, uint32_t opcode) {
 		// TODO: More sensible category?
 		mLOG(GBA, WARN, "Illegal opcode: %08x", opcode);
 	}
+	if (cpu->executionMode == MODE_THUMB && (opcode & 0xFFC0) == 0xE800) {
+		mLOG(GBA, DEBUG, "Hit Wii U VC opcode: %08x", opcode);
+		return;
+	}
 #ifdef USE_DEBUGGERS
 	if (gba->debugger) {
 		struct mDebuggerEntryInfo info = {