@@ -117,6 +117,7 @@ void (*reset)(struct ARMBoard* board);
 	void (*processEvents)(struct ARMBoard* board);
 	void (*swi16)(struct ARMBoard* board, int immediate);
 	void (*swi32)(struct ARMBoard* board, int immediate);
+	void (*hitIllegal)(struct ARMBoard* board, uint32_t opcode);
 	void (*readCPSR)(struct ARMBoard* board);
 
 	void (*hitStub)(struct ARMBoard* board, uint32_t opcode);

@@ -744,10 +744,18 @@ })
 
 // End branch definitions
 
+// Begin coprocessor definitions
+
+DEFINE_INSTRUCTION_ARM(CDP, ARM_STUB)
+DEFINE_INSTRUCTION_ARM(LDC, ARM_STUB)
+DEFINE_INSTRUCTION_ARM(STC, ARM_STUB)
+DEFINE_INSTRUCTION_ARM(MCR, ARM_STUB)
+DEFINE_INSTRUCTION_ARM(MRC, ARM_STUB)
+
 // Begin miscellaneous definitions
 
 DEFINE_INSTRUCTION_ARM(BKPT, ARM_STUB) // Not strictly in ARMv4T, but here for convenience
-DEFINE_INSTRUCTION_ARM(ILL, ARM_STUB) // Illegal opcode
+DEFINE_INSTRUCTION_ARM(ILL, ARM_ILL) // Illegal opcode
 
 DEFINE_INSTRUCTION_ARM(MSR,
 	int c = opcode & 0x00010000;
@@ -858,13 +866,12 @@ #define DECLARE_ARM_BRANCH_BLOCK(EMITTER, NAME) \
 	DO_256(DECLARE_INSTRUCTION_ARM(EMITTER, NAME))
 
 // TODO: Support coprocessors
-#define DECLARE_ARM_LOAD_STORE_COPROCESSOR_BLOCK(EMITTER, NAME, P, U, W, N) \
-	DO_8(0), \
-	DO_8(0)
+#define DECLARE_ARM_LOAD_STORE_COPROCESSOR_BLOCK(EMITTER, NAME, P, U, N, W) \
+	DO_8(DECLARE_INSTRUCTION_ARM(EMITTER, NAME)), \
+	DO_8(DECLARE_INSTRUCTION_ARM(EMITTER, NAME))
 
 #define DECLARE_ARM_COPROCESSOR_BLOCK(EMITTER, NAME1, NAME2) \
-	DO_8(DO_8(DO_INTERLACE(0, 0))), \
-	DO_8(DO_8(DO_INTERLACE(0, 0)))
+	DO_8(DO_8(DO_INTERLACE(DECLARE_INSTRUCTION_ARM(EMITTER, NAME1), DECLARE_INSTRUCTION_ARM(EMITTER, NAME2))))
 
 #define DECLARE_ARM_SWI_BLOCK(EMITTER) \
 	DO_256(DECLARE_INSTRUCTION_ARM(EMITTER, SWI))
@@ -1125,6 +1132,7 @@ DECLARE_ARM_LOAD_STORE_COPROCESSOR_BLOCK(EMITTER, LDC, P, U, N, ), \
 	DECLARE_ARM_LOAD_STORE_COPROCESSOR_BLOCK(EMITTER, STC, P, U, N, W), \
 	DECLARE_ARM_LOAD_STORE_COPROCESSOR_BLOCK(EMITTER, LDC, P, U, N, W), \
 	DECLARE_ARM_COPROCESSOR_BLOCK(EMITTER, CDP, MCR), \
+	DECLARE_ARM_COPROCESSOR_BLOCK(EMITTER, CDP, MRC), \
 	DECLARE_ARM_SWI_BLOCK(EMITTER)
 
 static const ARMInstruction _armTable[0x1000] = {

@@ -64,6 +64,7 @@ cpu->cycles += 4; \
 	}
 
 #define ARM_STUB cpu->board->hitStub(cpu->board, opcode)
+#define ARM_ILL cpu->board->hitIllegal(cpu->board, opcode)
 
 #define ARM_WRITE_PC \
 	cpu->gprs[ARM_PC] = (cpu->gprs[ARM_PC] & -WORD_SIZE_ARM) + WORD_SIZE_ARM; \

@@ -448,7 +448,7 @@ address -= 4;,
 	THUMB_STORE_POST_BODY,
 	cpu->gprs[ARM_SP] = address + 4)
 
-DEFINE_INSTRUCTION_THUMB(ILL, ARM_STUB)
+DEFINE_INSTRUCTION_THUMB(ILL, ARM_ILL)
 DEFINE_INSTRUCTION_THUMB(BKPT, ARM_STUB)
 DEFINE_INSTRUCTION_THUMB(B,
 	int16_t immediate = (opcode & 0x07FF) << 5;
@@ -589,7 +589,7 @@ DO_4(DECLARE_INSTRUCTION_THUMB(EMITTER, SWI)), \
 	DO_8(DO_4(DECLARE_INSTRUCTION_THUMB(EMITTER, B))), \
 	DO_8(DO_4(DECLARE_INSTRUCTION_THUMB(EMITTER, ILL))), \
 	DO_8(DO_4(DECLARE_INSTRUCTION_THUMB(EMITTER, BL1))), \
-	DO_8(DO_4(DECLARE_INSTRUCTION_THUMB(EMITTER, BL2))) \
+	DO_8(DO_4(DECLARE_INSTRUCTION_THUMB(EMITTER, BL2)))
 
 static const ThumbInstruction _thumbTable[0x400] = {
 	DECLARE_THUMB_EMITTER_BLOCK(_ThumbInstruction)

@@ -97,6 +97,7 @@
 static void GBAProcessEvents(struct ARMBoard* board);
 static int32_t GBATimersProcessEvents(struct GBA* gba, int32_t cycles);
 static void GBAHitStub(struct ARMBoard* board, uint32_t opcode);
+static void GBAIllegal(struct ARMBoard* board, uint32_t opcode);
 
 static void _checkOverrides(struct GBA* gba, uint32_t code);
 
@@ -146,6 +147,7 @@ board->d.reset = GBABoardReset;
 	board->d.processEvents = GBAProcessEvents;
 	board->d.swi16 = GBASwi16;
 	board->d.swi32 = GBASwi32;
+	board->d.hitIllegal = GBAIllegal;
 	board->d.readCPSR = GBATestIRQ;
 	board->d.hitStub = GBAHitStub;
 }
@@ -528,7 +530,16 @@ }
 #else
 	abort();
 #endif
+}
 
+void GBAIllegal(struct ARMBoard* board, uint32_t opcode) {
+	struct GBABoard* gbaBoard = (struct GBABoard*) board;
+	GBALog(gbaBoard->p, GBA_LOG_WARN, "Illegal opcode: %08x", opcode);
+#ifdef USE_DEBUGGER
+	if (gbaBoard->p->debugger) {
+		ARMDebuggerEnter(gbaBoard->p->debugger);
+	}
+#endif
 }
 
 void _checkOverrides(struct GBA* gba, uint32_t id) {