diff --git a/src/libcoreint/opcodes.c b/src/libcoreint/opcodes.c
index 071623144..a71a68a7a 100644
--- a/src/libcoreint/opcodes.c
+++ b/src/libcoreint/opcodes.c
@@ -13,6 +13,7 @@
  * limitations under the License.
  */
 
+#include "ecma-helpers.h"
 #include "ecma-operations.h"
 #include "interpreter.h"
 #include "jerry-libc.h"
@@ -66,13 +67,13 @@
     op(var_decl)
 
 #define DEFINE_UNIMPLEMENTED_OP(op) \
-  void opfunc_ ## op(OPCODE opdata, struct __int_data *int_data) { \
+  ecma_CompletionValue_t opfunc_ ## op(OPCODE opdata, struct __int_data *int_data) { \
     JERRY_UNIMPLEMENTED_REF_UNUSED_VARS( opdata, int_data); \
   }
 OP_UNIMPLEMENTED_LIST(DEFINE_UNIMPLEMENTED_OP)
 #undef DEFINE_UNIMPLEMENTED_OP
 
-void
+ecma_CompletionValue_t
 opfunc_loop_inf (OPCODE opdata, struct __int_data *int_data)
 {
 #ifdef __HOST
@@ -82,9 +83,13 @@ opfunc_loop_inf (OPCODE opdata, struct __int_data *int_data)
 #endif
 
   int_data->pos = opdata.data.loop_inf.loop_root;
+
+  return ecma_MakeCompletionValue( ECMA_COMPLETION_TYPE_NORMAL,
+                                   ecma_MakeSimpleValue( ECMA_SIMPLE_VALUE_EMPTY),
+                                   ECMA_TARGET_ID_RESERVED);
 }
 
-void
+ecma_CompletionValue_t
 opfunc_call_1 (OPCODE opdata __unused, struct __int_data *int_data)
 {
 #ifdef __HOST
@@ -95,9 +100,14 @@ opfunc_call_1 (OPCODE opdata __unused, struct __int_data *int_data)
 #endif
 
   int_data->pos++;
+
+  // FIXME
+  return ecma_MakeCompletionValue( ECMA_COMPLETION_TYPE_NORMAL,
+                                   ecma_MakeSimpleValue( ECMA_SIMPLE_VALUE_EMPTY),
+                                   ECMA_TARGET_ID_RESERVED);
 }
 
-void
+ecma_CompletionValue_t
 opfunc_jmp (OPCODE opdata, struct __int_data *int_data)
 {
 #ifdef __HOST
@@ -107,6 +117,10 @@ opfunc_jmp (OPCODE opdata, struct __int_data *int_data)
 #endif
 
   int_data->pos = opdata.data.jmp.opcode_idx;
+
+  return ecma_MakeCompletionValue( ECMA_COMPLETION_TYPE_NORMAL,
+                                   ecma_MakeSimpleValue( ECMA_SIMPLE_VALUE_EMPTY),
+                                   ECMA_TARGET_ID_RESERVED);
 }
 
 /** Opcode generators.  */
diff --git a/src/libcoreint/opcodes.h b/src/libcoreint/opcodes.h
index 777f76c64..7dd1d8752 100644
--- a/src/libcoreint/opcodes.h
+++ b/src/libcoreint/opcodes.h
@@ -16,6 +16,7 @@
 #ifndef OPCODES_H
 #define	OPCODES_H
 
+#include "ecma-globals.h"
 #include "globals.h"
 
 #define OPCODE struct __opcode
@@ -23,7 +24,7 @@ struct __int_data;
 
 #define OP_STRUCT_FIELD(name) struct __op_##name name;
 #define OP_ENUM_FIELD(name) __op__idx_##name ,
-#define OP_FUNC_DECL(name) void opfunc_##name  (OPCODE, struct __int_data *);
+#define OP_FUNC_DECL(name) ecma_CompletionValue_t opfunc_##name  (OPCODE, struct __int_data *);
 
 /** A single bytecode instruction is 32bit wide and has an 8bit opcode field
  and several operand of 8 of 16 bit.*/
@@ -32,7 +33,7 @@ struct __int_data;
 #define T_IDX uint8_t /** index values */
 
 OPCODE;
-typedef void (*opfunc)(OPCODE, struct __int_data *);
+typedef ecma_CompletionValue_t (*opfunc)(OPCODE, struct __int_data *);
 
 #define OP_LOOPS(op)                    \
     op(loop_inf)                        \