diff --git a/Makefile b/Makefile
index 1f3a537d4..82d36fea2 100644
--- a/Makefile
+++ b/Makefile
@@ -15,10 +15,9 @@
 #
 # Target naming scheme
 #
-#   Main targets: {dev,debug,release,debug_release}.{linux,stm32f{4}}[.{check,flash}]
+#   Main targets: {debug,release,debug_release}.{linux,stm32f{4}}[.{check,flash}]
 #
 #    Target mode part (before dot):
-#       dev:           - JERRY_NDEBUG; - optimizations; + debug symbols; - -Werror  | local development build
 #       debug:         - JERRY_NDEBUG; - optimizations; + debug symbols; + -Werror  | debug build
 #       debug_release: - JERRY_NDEBUG; + optimizations; + debug symbols; + -Werror  | checked release build
 #       release:       + JERRY_NDEBUG; + optimizations; - debug symbols; + -Werror  | release build
@@ -35,7 +34,7 @@
 #   Unit test target: unittests
 #
 
-export TARGET_MODES = dev debug debug_release release
+export TARGET_MODES = debug debug_release release
 export TARGET_PC_SYSTEMS = linux
 export TARGET_MCU_SYSTEMS = $(addprefix stm32f,4) # now only stm32f4 is supported, to add, for example, to stm32f3, change to $(addprefix stm32f,3 4)
 export TARGET_SYSTEMS = $(TARGET_PC_SYSTEMS) $(TARGET_MCU_SYSTEMS)
diff --git a/Makefile.mak b/Makefile.mak
index ec77a95d2..fdc510b62 100644
--- a/Makefile.mak
+++ b/Makefile.mak
@@ -59,13 +59,6 @@ else
  OPTION_OPTIMIZE = disable
 endif
 
-# -Werror
-ifeq ($(TARGET_MODE),dev)
- OPTION_WERROR = disable
-else
- OPTION_WERROR = enable
-endif
-
 # Is MCU target?
 ifeq ($(filter-out $(TARGET_MCU_SYSTEMS),$(TARGET_SYSTEM)),)
 	OPTION_MCU = enable
@@ -149,7 +142,7 @@ endif
 # Jerry part sources, headers, includes, cflags, ldflags
 #
 
-CFLAGS_JERRY = $(CFLAGS_WARNINGS)
+CFLAGS_JERRY = $(CFLAGS_WARNINGS) $(CFLAGS_WERROR)
 DEFINES_JERRY = -DMEM_HEAP_CHUNK_SIZE=256 -DMEM_HEAP_AREA_SIZE=32768 -DMEM_STATS
 
 # FIXME:
@@ -181,10 +174,6 @@ ifeq ($(OPTION_NDEBUG),enable)
  DEFINES_JERRY += -DJERRY_NDEBUG
 endif
 
-ifeq ($(OPTION_WERROR),enable)
- CFLAGS_JERRY += $(CFLAGS_WERROR)
-endif
-
 ifeq ($(OPTION_MCU),disable)
  DEFINES_JERRY += -D__HOST -DJERRY_SOURCE_BUFFER_SIZE=1048576
 else
diff --git a/src/libcoreint/opcodes.c b/src/libcoreint/opcodes.c
index 783ab449f..edc27460a 100644
--- a/src/libcoreint/opcodes.c
+++ b/src/libcoreint/opcodes.c
@@ -14,11 +14,13 @@
  */
 
 #include "ecma-alloc.h"
+#include "ecma-comparison.h"
 #include "ecma-conversion.h"
 #include "ecma-exceptions.h"
 #include "ecma-helpers.h"
 #include "ecma-number-arithmetic.h"
 #include "ecma-operations.h"
+#include "ecma-try-catch-macro.h"
 #include "globals.h"
 #include "interpreter.h"
 #include "jerry-libc.h"
@@ -39,52 +41,19 @@
  *
  *      1. At the beginning of the handler there should be declared opcode handler's 'return value' variable.
  *
- *      2. All exceptionable operations except the last should be enclosed in TRY_CATCH macro.
+ *      2. All exceptionable operations except the last should be enclosed in ECMA_TRY_CATCH macro.
  *         All subsequent operations in the opcode handler should be placed into block between
- *         the TRY_CATCH and corresponding FINALIZE.
+ *         the ECMA_TRY_CATCH and corresponding ECMA_FINALIZE.
  *
  *      3. The last exceptionable's operation result should be assigned directly to opcode handler's
- *         'return value' variable without using TRY_CATCH macro.
+ *         'return value' variable without using ECMA_TRY_CATCH macro.
  *
- *      4. After last FINALIZE statement there should be only one operator.
+ *      4. After last ECMA_FINALIZE statement there should be only one operator.
  *         The operator should return from the opcode handler with it's 'return value'.
  *
  *      5. No other operations with opcode handler's 'return value' variable should be performed.
  */
 
-/**
- * The macro defines try-block that initializes variable 'var' with 'op'
- * and checks for exceptions that might be thrown during initialization.
- *
- * If no exception was thrown, then code after the try-block is executed.
- * Otherwise, throw-completion value is just copied to return_value.
- *
- * Note:
- *      Each TRY_CATCH should have it's own corresponding FINALIZE
- *      statement with same argument as corresponding TRY_CATCH's first argument.
- */
-#define TRY_CATCH(var, op, return_value) \
-  ecma_completion_value_t var = op; \
-  if ( unlikely( ecma_is_completion_value_throw( var) ) ) \
-  { \
-    return_value = ecma_copy_completion_value( var); \
-  } \
-  else \
-  { \
-    JERRY_ASSERT( ecma_is_completion_value_normal( var) )
-
-/**
- * The macro marks end of code block that is executed if no exception
- * was catched by corresponding TRY_CATCH and frees variable,
- * initialized by the TRY_CATCH.
- *
- * Note:
- *      Each TRY_CATCH should be followed by FINALIZE with same
- *      argument as corresponding TRY_CATCH's first argument.
- */
-#define FINALIZE(var) } \
-  ecma_free_completion_value( var)
-
 /**
  * String literal copy descriptor.
  */
@@ -312,8 +281,8 @@ do_number_arithmetic(struct __int_data *int_data, /**< interpreter context */
 {
   ecma_completion_value_t ret_value;
 
-  TRY_CATCH(num_left_value, ecma_op_to_number( left_value), ret_value);
-  TRY_CATCH(num_right_value, ecma_op_to_number( right_value), ret_value);
+  ECMA_TRY_CATCH(num_left_value, ecma_op_to_number( left_value), ret_value);
+  ECMA_TRY_CATCH(num_right_value, ecma_op_to_number( right_value), ret_value);
 
   ecma_number_t *left_p, *right_p, *res_p;
   left_p = (ecma_number_t*)ecma_get_pointer( num_left_value.value.value);
@@ -346,8 +315,8 @@ do_number_arithmetic(struct __int_data *int_data, /**< interpreter context */
 
   ecma_dealloc_number( res_p);
 
-  FINALIZE( num_right_value);
-  FINALIZE( num_left_value);
+  ECMA_FINALIZE( num_right_value);
+  ECMA_FINALIZE( num_left_value);
 
   return ret_value;
 } /* do_number_arithmetic */
@@ -372,12 +341,8 @@ do_number_arithmetic(struct __int_data *int_data, /**< interpreter context */
     op(b_xor)                           \
     op(logical_and)                     \
     op(logical_or)                      \
-    op(equal_value)                     \
-    op(not_equal_value)                 \
     op(equal_value_type)                \
     op(not_equal_value_type)            \
-    op(less_than)                       \
-    op(greater_than)                    \
     op(less_or_equal_than)              \
     op(greater_or_equal_than)           \
     op(nop)                             \
@@ -446,13 +411,13 @@ opfunc_call_1 (OPCODE opdata __unused, struct __int_data *int_data)
   
   if (!__strcmp ((const char*)str_value.str_p, "LEDToggle"))
   {
-    TRY_CATCH (cond_value, get_variable_value (int_data, opdata.data.call_1.arg1_lit_idx, false), ret_value);
+    ECMA_TRY_CATCH (cond_value, get_variable_value (int_data, opdata.data.call_1.arg1_lit_idx, false), ret_value);
     JERRY_ASSERT(cond_value.value.value_type == ECMA_TYPE_NUMBER );
     ecma_number_t * num_p = (ecma_number_t*)ecma_get_pointer(cond_value.value.value);
     uint32_t int_num = (uint32_t)*num_p;
     led_blink_once (int_num);
     ret_value = ecma_make_empty_completion_value ();
-    FINALIZE (cond_value);
+    ECMA_FINALIZE (cond_value);
   }
 
   free_string_literal_copy (&str_value);
@@ -476,7 +441,7 @@ opfunc_is_true_jmp (OPCODE opdata, /**< operation data */
 
   ecma_completion_value_t ret_value;
 
-  TRY_CATCH(cond_value, get_variable_value( int_data, cond_var_idx, false), ret_value);
+  ECMA_TRY_CATCH(cond_value, get_variable_value( int_data, cond_var_idx, false), ret_value);
 
   ecma_completion_value_t to_bool_completion = ecma_op_to_boolean( cond_value.value);
   JERRY_ASSERT( ecma_is_completion_value_normal( to_bool_completion) );
@@ -492,7 +457,7 @@ opfunc_is_true_jmp (OPCODE opdata, /**< operation data */
 
   ret_value = ecma_make_empty_completion_value();
 
-  FINALIZE(cond_value);
+  ECMA_FINALIZE(cond_value);
 
   return ret_value;
 } /* opfunc_is_true_jmp */
@@ -513,7 +478,7 @@ opfunc_is_false_jmp (OPCODE opdata, /**< operation data */
 
   ecma_completion_value_t ret_value;
 
-  TRY_CATCH(cond_value, get_variable_value( int_data, cond_var_idx, false), ret_value);
+  ECMA_TRY_CATCH(cond_value, get_variable_value( int_data, cond_var_idx, false), ret_value);
 
   ecma_completion_value_t to_bool_completion = ecma_op_to_boolean( cond_value.value);
   JERRY_ASSERT( ecma_is_completion_value_normal( to_bool_completion) );
@@ -529,7 +494,7 @@ opfunc_is_false_jmp (OPCODE opdata, /**< operation data */
 
   ret_value = ecma_make_empty_completion_value();
 
-  FINALIZE(cond_value);
+  ECMA_FINALIZE(cond_value);
 
   return ret_value;
 } /* opfunc_is_false_jmp */
@@ -700,10 +665,10 @@ opfunc_addition(OPCODE opdata, /**< operation data */
 
   ecma_completion_value_t ret_value;
 
-  TRY_CATCH(left_value, get_variable_value( int_data, left_var_idx, false), ret_value);
-  TRY_CATCH(right_value, get_variable_value( int_data, right_var_idx, false), ret_value);
-  TRY_CATCH(prim_left_value, ecma_op_to_primitive( left_value.value), ret_value);
-  TRY_CATCH(prim_right_value, ecma_op_to_primitive( right_value.value), ret_value);
+  ECMA_TRY_CATCH(left_value, get_variable_value( int_data, left_var_idx, false), ret_value);
+  ECMA_TRY_CATCH(right_value, get_variable_value( int_data, right_var_idx, false), ret_value);
+  ECMA_TRY_CATCH(prim_left_value, ecma_op_to_primitive( left_value.value, ECMA_PREFERRED_TYPE_NO), ret_value);
+  ECMA_TRY_CATCH(prim_right_value, ecma_op_to_primitive( right_value.value, ECMA_PREFERRED_TYPE_NO), ret_value);
 
   if ( prim_left_value.value.value_type == ECMA_TYPE_STRING
        || prim_right_value.value.value_type == ECMA_TYPE_STRING )
@@ -719,10 +684,10 @@ opfunc_addition(OPCODE opdata, /**< operation data */
                                        prim_right_value.value);
     }
 
-  FINALIZE(prim_right_value);
-  FINALIZE(prim_left_value);
-  FINALIZE(right_value);
-  FINALIZE(left_value);
+  ECMA_FINALIZE(prim_right_value);
+  ECMA_FINALIZE(prim_left_value);
+  ECMA_FINALIZE(right_value);
+  ECMA_FINALIZE(left_value);
 
   return ret_value;
 } /* opfunc_addition */
@@ -747,8 +712,8 @@ opfunc_substraction(OPCODE opdata, /**< operation data */
 
   ecma_completion_value_t ret_value;
 
-  TRY_CATCH(left_value, get_variable_value( int_data, left_var_idx, false), ret_value);
-  TRY_CATCH(right_value, get_variable_value( int_data, right_var_idx, false), ret_value);
+  ECMA_TRY_CATCH(left_value, get_variable_value( int_data, left_var_idx, false), ret_value);
+  ECMA_TRY_CATCH(right_value, get_variable_value( int_data, right_var_idx, false), ret_value);
 
   ret_value = do_number_arithmetic(int_data,
                                    dst_var_idx,
@@ -756,8 +721,8 @@ opfunc_substraction(OPCODE opdata, /**< operation data */
                                    left_value.value,
                                    right_value.value);
 
-  FINALIZE(right_value);
-  FINALIZE(left_value);
+  ECMA_FINALIZE(right_value);
+  ECMA_FINALIZE(left_value);
 
   return ret_value;
 } /* opfunc_substraction */
@@ -782,8 +747,8 @@ opfunc_multiplication(OPCODE opdata, /**< operation data */
 
   ecma_completion_value_t ret_value;
 
-  TRY_CATCH(left_value, get_variable_value( int_data, left_var_idx, false), ret_value);
-  TRY_CATCH(right_value, get_variable_value( int_data, right_var_idx, false), ret_value);
+  ECMA_TRY_CATCH(left_value, get_variable_value( int_data, left_var_idx, false), ret_value);
+  ECMA_TRY_CATCH(right_value, get_variable_value( int_data, right_var_idx, false), ret_value);
 
   ret_value = do_number_arithmetic(int_data,
                                    dst_var_idx,
@@ -791,8 +756,8 @@ opfunc_multiplication(OPCODE opdata, /**< operation data */
                                    left_value.value,
                                    right_value.value);
 
-  FINALIZE(right_value);
-  FINALIZE(left_value);
+  ECMA_FINALIZE(right_value);
+  ECMA_FINALIZE(left_value);
 
   return ret_value;
 } /* opfunc_multiplication */
@@ -817,8 +782,8 @@ opfunc_division(OPCODE opdata, /**< operation data */
 
   ecma_completion_value_t ret_value;
 
-  TRY_CATCH(left_value, get_variable_value( int_data, left_var_idx, false), ret_value);
-  TRY_CATCH(right_value, get_variable_value( int_data, right_var_idx, false), ret_value);
+  ECMA_TRY_CATCH(left_value, get_variable_value( int_data, left_var_idx, false), ret_value);
+  ECMA_TRY_CATCH(right_value, get_variable_value( int_data, right_var_idx, false), ret_value);
 
   ret_value = do_number_arithmetic(int_data,
                                    dst_var_idx,
@@ -826,8 +791,8 @@ opfunc_division(OPCODE opdata, /**< operation data */
                                    left_value.value,
                                    right_value.value);
 
-  FINALIZE(right_value);
-  FINALIZE(left_value);
+  ECMA_FINALIZE(right_value);
+  ECMA_FINALIZE(left_value);
 
   return ret_value;
 } /* opfunc_division */
@@ -852,8 +817,8 @@ opfunc_remainder(OPCODE opdata, /**< operation data */
 
   ecma_completion_value_t ret_value;
 
-  TRY_CATCH(left_value, get_variable_value( int_data, left_var_idx, false), ret_value);
-  TRY_CATCH(right_value, get_variable_value( int_data, right_var_idx, false), ret_value);
+  ECMA_TRY_CATCH(left_value, get_variable_value( int_data, left_var_idx, false), ret_value);
+  ECMA_TRY_CATCH(right_value, get_variable_value( int_data, right_var_idx, false), ret_value);
 
   ret_value = do_number_arithmetic(int_data,
                                    dst_var_idx,
@@ -861,12 +826,181 @@ opfunc_remainder(OPCODE opdata, /**< operation data */
                                    left_value.value,
                                    right_value.value);
 
-  FINALIZE(right_value);
-  FINALIZE(left_value);
+  ECMA_FINALIZE(right_value);
+  ECMA_FINALIZE(left_value);
 
   return ret_value;
 } /* opfunc_remainder */
 
+/**
+ * 'Equals' opcode handler.
+ *
+ * See also: ECMA-262 v5, 11.9.1
+ *
+ * @return completion value
+ *         Returned value must be freed with ecma_free_completion_value
+ */
+ecma_completion_value_t
+opfunc_equal_value(OPCODE opdata, /**< operation data */
+                   struct __int_data *int_data) /**< interpreter context */
+{
+  const T_IDX dst_var_idx = opdata.data.equal_value.dst;
+  const T_IDX left_var_idx = opdata.data.equal_value.var_left;
+  const T_IDX right_var_idx = opdata.data.equal_value.var_right;
+
+  int_data->pos++;
+
+  ecma_completion_value_t ret_value;
+
+  ECMA_TRY_CATCH(left_value, get_variable_value( int_data, left_var_idx, false), ret_value);
+  ECMA_TRY_CATCH(right_value, get_variable_value( int_data, right_var_idx, false), ret_value);
+
+  bool is_equal = ecma_op_abstract_equality_compare( left_value.value, right_value.value);
+
+  ret_value = set_variable_value( int_data, dst_var_idx, ecma_make_simple_value (is_equal ? ECMA_SIMPLE_VALUE_TRUE
+                                                                                          : ECMA_SIMPLE_VALUE_FALSE));
+
+  ECMA_FINALIZE(right_value);
+  ECMA_FINALIZE(left_value);
+
+  return ret_value;
+} /* opfunc_equal_value */
+
+/**
+ * 'Does-not-equals' opcode handler.
+ *
+ * See also: ECMA-262 v5, 11.9.2
+ *
+ * @return completion value
+ *         Returned value must be freed with ecma_free_completion_value
+ */
+ecma_completion_value_t
+opfunc_not_equal_value(OPCODE opdata, /**< operation data */
+                       struct __int_data *int_data) /**< interpreter context */
+{
+  const T_IDX dst_var_idx = opdata.data.not_equal_value.dst;
+  const T_IDX left_var_idx = opdata.data.not_equal_value.var_left;
+  const T_IDX right_var_idx = opdata.data.not_equal_value.var_right;
+
+  int_data->pos++;
+
+  ecma_completion_value_t ret_value;
+
+  ECMA_TRY_CATCH(left_value, get_variable_value( int_data, left_var_idx, false), ret_value);
+  ECMA_TRY_CATCH(right_value, get_variable_value( int_data, right_var_idx, false), ret_value);
+
+  bool is_equal = ecma_op_abstract_equality_compare( left_value.value, right_value.value);
+
+  ret_value = set_variable_value( int_data, dst_var_idx, ecma_make_simple_value (is_equal ? ECMA_SIMPLE_VALUE_FALSE
+                                                                                          : ECMA_SIMPLE_VALUE_TRUE));
+
+
+  ECMA_FINALIZE(right_value);
+  ECMA_FINALIZE(left_value);
+
+  return ret_value;
+} /* opfunc_not_equal_value */
+
+/**
+ * 'Less-than' opcode handler.
+ *
+ * See also: ECMA-262 v5, 11.8.1
+ *
+ * @return completion value
+ *         Returned value must be freed with ecma_free_completion_value
+ */
+ecma_completion_value_t
+opfunc_less_than(OPCODE opdata, /**< operation data */
+                 struct __int_data *int_data) /**< interpreter context */
+{
+  const T_IDX dst_var_idx = opdata.data.less_than.dst;
+  const T_IDX left_var_idx = opdata.data.less_than.var_left;
+  const T_IDX right_var_idx = opdata.data.less_than.var_right;
+
+  int_data->pos++;
+
+  ecma_completion_value_t ret_value;
+
+  ECMA_TRY_CATCH(left_value, get_variable_value( int_data, left_var_idx, false), ret_value);
+  ECMA_TRY_CATCH(right_value, get_variable_value( int_data, right_var_idx, false), ret_value);
+  ECMA_TRY_CATCH(compare_result,
+                 ecma_op_abstract_relational_compare (left_value.value,
+                                                      right_value.value,
+                                                      true),
+                 ret_value);
+
+  ecma_simple_value_t res;
+
+  if ( ecma_is_value_undefined( compare_result.value) )
+    {
+      res = ECMA_SIMPLE_VALUE_FALSE;
+    }
+  else
+    {
+      JERRY_ASSERT( ecma_is_value_boolean( compare_result.value) );
+
+      res = compare_result.value.value;
+    }
+
+  ret_value = set_variable_value( int_data, dst_var_idx, ecma_make_simple_value( res));
+
+  ECMA_FINALIZE(compare_result);
+  ECMA_FINALIZE(right_value);
+  ECMA_FINALIZE(left_value);
+
+  return ret_value;
+} /* opfunc_less_than */
+
+/**
+ * 'Greater-than' opcode handler.
+ *
+ * See also: ECMA-262 v5, 11.8.2
+ *
+ * @return completion value
+ *         Returned value must be freed with ecma_free_completion_value
+ */
+ecma_completion_value_t
+opfunc_greater_than(OPCODE opdata, /**< operation data */
+                    struct __int_data *int_data) /**< interpreter context */
+{
+  const T_IDX dst_var_idx = opdata.data.greater_than.dst;
+  const T_IDX left_var_idx = opdata.data.greater_than.var_left;
+  const T_IDX right_var_idx = opdata.data.greater_than.var_right;
+
+  int_data->pos++;
+
+  ecma_completion_value_t ret_value;
+
+  ECMA_TRY_CATCH(left_value, get_variable_value( int_data, left_var_idx, false), ret_value);
+  ECMA_TRY_CATCH(right_value, get_variable_value( int_data, right_var_idx, false), ret_value);
+  ECMA_TRY_CATCH(compare_result,
+                 ecma_op_abstract_relational_compare (right_value.value,
+                                                      left_value.value,
+                                                      false),
+                 ret_value);
+
+  ecma_simple_value_t res;
+
+  if ( ecma_is_value_undefined( compare_result.value) )
+    {
+      res = ECMA_SIMPLE_VALUE_FALSE;
+    }
+  else
+    {
+      JERRY_ASSERT( ecma_is_value_boolean( compare_result.value) );
+
+      res = compare_result.value.value;
+    }
+
+  ret_value = set_variable_value( int_data, dst_var_idx, ecma_make_simple_value( res));
+
+  ECMA_FINALIZE(compare_result);
+  ECMA_FINALIZE(right_value);
+  ECMA_FINALIZE(left_value);
+
+  return ret_value;
+} /* opfunc_greater_than */
+
 /**
  * 'Register variable declaration' opcode handler.
  *
diff --git a/src/libecmaoperations/ecma-comparison.c b/src/libecmaoperations/ecma-comparison.c
index d07025431..e695d71c5 100644
--- a/src/libecmaoperations/ecma-comparison.c
+++ b/src/libecmaoperations/ecma-comparison.c
@@ -14,7 +14,9 @@
  */
 
 #include "ecma-comparison.h"
+#include "ecma-conversion.h"
 #include "ecma-globals.h"
+#include "ecma-try-catch-macro.h"
 #include "globals.h"
 
 /** \addtogroup ecma ---TODO---
@@ -33,8 +35,8 @@
  *         false - otherwise.
  */
 bool
-ecma_abstract_equality_compare(ecma_value_t x, /**< first operand */
-                               ecma_value_t y) /**< second operand */
+ecma_op_abstract_equality_compare(ecma_value_t x, /**< first operand */
+                                  ecma_value_t y) /**< second operand */
 {
   const bool is_x_undefined = ecma_is_value_undefined( x);
   const bool is_x_null = ecma_is_value_null( x);
@@ -97,7 +99,75 @@ ecma_abstract_equality_compare(ecma_value_t x, /**< first operand */
   {
     JERRY_UNIMPLEMENTED();
   }
-} /* ecma_abstract_equality_compare */
+} /* ecma_op_abstract_equality_compare */
+
+/**
+ * ECMA abstract relational comparison routine.
+ *
+ * See also: ECMA-262 v5, 11.8.5
+ *
+ * @return completion value
+ *         Returned value must be freed with ecma_free_completion_value
+ */
+ecma_completion_value_t
+ecma_op_abstract_relational_compare(ecma_value_t x, /**< first operand */
+                                    ecma_value_t y, /**< second operand */
+                                    bool left_first) /**< 'LeftFirst' flag */
+{
+  ecma_completion_value_t ret_value, px, py;
+
+  ecma_value_t first_converted_value = left_first ? x : y;
+  ecma_value_t second_converted_value = left_first ? y : x;
+
+  // 1., 2.
+  ECMA_TRY_CATCH( prim_first_converted_value, ecma_op_to_primitive( first_converted_value, ECMA_PREFERRED_TYPE_NUMBER), ret_value);
+  ECMA_TRY_CATCH( prim_second_converted_value, ecma_op_to_primitive( second_converted_value, ECMA_PREFERRED_TYPE_NUMBER), ret_value);
+
+  px = left_first ? prim_first_converted_value : prim_second_converted_value;
+  py = left_first ? prim_second_converted_value : prim_first_converted_value;
+
+  const bool is_px_string = ( px.value.value_type == ECMA_TYPE_STRING );
+  const bool is_py_string = ( py.value.value_type == ECMA_TYPE_STRING );
+
+  if ( !( is_px_string && is_py_string ) )
+    { // 3.
+      // a.
+      ECMA_TRY_CATCH( nx, ecma_op_to_number( px.value), ret_value);
+
+      // b.
+      ECMA_TRY_CATCH( ny, ecma_op_to_number( py.value), ret_value);
+
+      ecma_number_t* num_x_p = (ecma_number_t*)ecma_get_pointer( nx.value.value);
+      ecma_number_t* num_y_p = (ecma_number_t*)ecma_get_pointer( ny.value.value);
+
+      TODO( /* Implement according to ECMA */ );
+
+      if ( *num_x_p >= *num_y_p )
+        {
+          ret_value = ecma_make_completion_value (ECMA_COMPLETION_TYPE_NORMAL,
+                                                  ecma_make_simple_value( ECMA_SIMPLE_VALUE_FALSE),
+                                                  ECMA_TARGET_ID_RESERVED);
+        }
+      else
+        {
+          ret_value = ecma_make_completion_value (ECMA_COMPLETION_TYPE_NORMAL,
+                                                  ecma_make_simple_value( ECMA_SIMPLE_VALUE_TRUE),
+                                                  ECMA_TARGET_ID_RESERVED);
+        }
+
+      ECMA_FINALIZE( ny);
+      ECMA_FINALIZE( nx);
+    }
+  else
+    { // 4.
+      JERRY_UNIMPLEMENTED();
+    }
+
+  ECMA_FINALIZE( prim_second_converted_value);
+  ECMA_FINALIZE( prim_first_converted_value);
+
+  return ret_value;
+} /* ecma_op_abstract_relational_compare */
 
 /**
  * @}
diff --git a/src/libecmaoperations/ecma-comparison.h b/src/libecmaoperations/ecma-comparison.h
index bdb305578..50c8fc525 100644
--- a/src/libecmaoperations/ecma-comparison.h
+++ b/src/libecmaoperations/ecma-comparison.h
@@ -26,7 +26,8 @@
  * @{
  */
 
-extern bool ecma_abstract_equality_compare( ecma_value_t x, ecma_value_t y);
+extern bool ecma_op_abstract_equality_compare( ecma_value_t x, ecma_value_t y);
+extern ecma_completion_value_t ecma_op_abstract_relational_compare(ecma_value_t x, ecma_value_t y, bool left_first);
 
 /**
  * @}
diff --git a/src/libecmaoperations/ecma-conversion.c b/src/libecmaoperations/ecma-conversion.c
index df77f9b5a..b42a90f0b 100644
--- a/src/libecmaoperations/ecma-conversion.c
+++ b/src/libecmaoperations/ecma-conversion.c
@@ -91,7 +91,8 @@ ecma_op_check_object_coercible( ecma_value_t value) /**< ecma-value */
  *         Returned value must be freed with ecma_free_completion_value
  */
 ecma_completion_value_t
-ecma_op_to_primitive( ecma_value_t value) /**< ecma-value */
+ecma_op_to_primitive( ecma_value_t value, /**< ecma-value */
+                      ecma_preferred_type_hint preferred_type) /**< preferred type hint */
 {
   switch ( (ecma_type_t)value.value_type )
   {
@@ -105,7 +106,7 @@ ecma_op_to_primitive( ecma_value_t value) /**< ecma-value */
       }
     case ECMA_TYPE_OBJECT:
       {
-        JERRY_UNIMPLEMENTED();
+        JERRY_UNIMPLEMENTED_REF_UNUSED_VARS(preferred_type);
       }
     case ECMA_TYPE__COUNT:
       {
@@ -215,7 +216,7 @@ ecma_op_to_number( ecma_value_t value) /**< ecma-value */
       }
     case ECMA_TYPE_OBJECT:
       {
-        ecma_completion_value_t completion_to_primitive = ecma_op_to_primitive( value);
+        ecma_completion_value_t completion_to_primitive = ecma_op_to_primitive( value, ECMA_PREFERRED_TYPE_NUMBER);
         JERRY_ASSERT( ecma_is_completion_value_normal( completion_to_primitive) );
 
         ecma_completion_value_t completion_to_number = ecma_op_to_number( completion_to_primitive.value);
diff --git a/src/libecmaoperations/ecma-conversion.h b/src/libecmaoperations/ecma-conversion.h
index eaa02eb39..1fbc67b01 100644
--- a/src/libecmaoperations/ecma-conversion.h
+++ b/src/libecmaoperations/ecma-conversion.h
@@ -26,8 +26,22 @@
  * @{
  */
 
+/**
+ * Second argument of 'ToPrimitive' operation that is a hint,
+ * specifying the preferred type of conversion result.
+ */
+typedef enum
+{
+  ECMA_PREFERRED_TYPE_NO, /**< no preferred type is specified */
+  ECMA_PREFERRED_TYPE_UNDEFINED, /**< Undefined */
+  ECMA_PREFERRED_TYPE_NULL, /**< Null */
+  ECMA_PREFERRED_TYPE_BOOLEAN, /**< Boolean */
+  ECMA_PREFERRED_TYPE_NUMBER, /**< Number */
+  ECMA_PREFERRED_TYPE_STRING /**< String */
+} ecma_preferred_type_hint;
+
 extern ecma_completion_value_t ecma_op_check_object_coercible( ecma_value_t value);
-extern ecma_completion_value_t ecma_op_to_primitive( ecma_value_t value);
+extern ecma_completion_value_t ecma_op_to_primitive( ecma_value_t value, ecma_preferred_type_hint preferred_type);
 extern ecma_completion_value_t ecma_op_to_boolean( ecma_value_t value);
 extern ecma_completion_value_t ecma_op_to_number( ecma_value_t value);
 extern ecma_completion_value_t ecma_op_to_object( ecma_value_t value);
diff --git a/src/libecmaoperations/ecma-try-catch-macro.h b/src/libecmaoperations/ecma-try-catch-macro.h
new file mode 100644
index 000000000..1b47559ef
--- /dev/null
+++ b/src/libecmaoperations/ecma-try-catch-macro.h
@@ -0,0 +1,52 @@
+/* Copyright 2014 Samsung Electronics Co., Ltd.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef ECMA_TRY_CATCH_MACRO_H
+#define ECMA_TRY_CATCH_MACRO_H
+
+/**
+ * The macro defines try-block that initializes variable 'var' with 'op'
+ * and checks for exceptions that might be thrown during initialization.
+ *
+ * If no exception was thrown, then code after the try-block is executed.
+ * Otherwise, throw-completion value is just copied to return_value.
+ *
+ * Note:
+ *      Each ECMA_TRY_CATCH should have it's own corresponding ECMA_FINALIZE
+ *      statement with same argument as corresponding ECMA_TRY_CATCH's first argument.
+ */
+#define ECMA_TRY_CATCH(var, op, return_value) \
+  ecma_completion_value_t var = op; \
+  if ( unlikely( ecma_is_completion_value_throw( var) ) ) \
+  { \
+    return_value = ecma_copy_completion_value( var); \
+  } \
+  else \
+  { \
+    JERRY_ASSERT( ecma_is_completion_value_normal( var) )
+
+/**
+ * The macro marks end of code block that is executed if no exception
+ * was catched by corresponding ECMA_TRY_CATCH and frees variable,
+ * initialized by the ECMA_TRY_CATCH.
+ *
+ * Note:
+ *      Each ECMA_TRY_CATCH should be followed by ECMA_FINALIZE with same
+ *      argument as corresponding ECMA_TRY_CATCH's first argument.
+ */
+#define ECMA_FINALIZE(var) } \
+  ecma_free_completion_value( var)
+
+#endif /* !ECMA_TRY_CATCH_MACRO_H */
diff --git a/tests/unit/test_addition_opcode_number_operands.c b/tests/unit/test_addition_opcode_number_operands.c
index 683432222..0ebeadfe4 100644
--- a/tests/unit/test_addition_opcode_number_operands.c
+++ b/tests/unit/test_addition_opcode_number_operands.c
@@ -17,6 +17,7 @@
 #include "interpreter.h"
 #include "mem-allocator.h"
 #include "opcodes.h"
+#include "serializer.h"
 
 /**
  * Unit test's main function.
@@ -37,6 +38,12 @@ main( int __unused argc,
 
   mem_init();
 
+  const char *strings[] = { "a",
+                            "b" };
+  int nums [] = { 2 };
+  uint8_t offset = serializer_dump_strings( strings, 2);
+  serializer_dump_nums( nums, 1, offset, 2);
+
   init_int( test_program);
 
   return run_int() ? 0
diff --git a/tests/unit/test_assignment_opcode.c b/tests/unit/test_assignment_opcode.c
index d138cf377..ef8950da2 100644
--- a/tests/unit/test_assignment_opcode.c
+++ b/tests/unit/test_assignment_opcode.c
@@ -17,6 +17,7 @@
 #include "interpreter.h"
 #include "mem-allocator.h"
 #include "opcodes.h"
+#include "serializer.h"
 
 /**
  * Unit test's main function.
@@ -42,6 +43,12 @@ main( int __unused argc,
 
   mem_init();
 
+  const char *strings[] = { "a",
+                            "b" };
+  int nums [] = { 2 };
+  uint8_t offset = serializer_dump_strings( strings, 2);
+  serializer_dump_nums( nums, 1, offset, 2);
+
   init_int( test_program);
 
   return run_int() ? 0
diff --git a/tests/unit/test_division_opcode.c b/tests/unit/test_division_opcode.c
index 5c1c121ac..32e22cf0d 100644
--- a/tests/unit/test_division_opcode.c
+++ b/tests/unit/test_division_opcode.c
@@ -17,6 +17,7 @@
 #include "interpreter.h"
 #include "mem-allocator.h"
 #include "opcodes.h"
+#include "serializer.h"
 
 /**
  * Unit test's main function.
@@ -37,6 +38,12 @@ main( int __unused argc,
 
   mem_init();
 
+  const char *strings[] = { "a",
+                            "b" };
+  int nums [] = { 2 };
+  uint8_t offset = serializer_dump_strings( strings, 2);
+  serializer_dump_nums( nums, 1, offset, 2);
+
   init_int( test_program);
 
   return run_int() ? 0
diff --git a/tests/unit/test_multiplication_opcode.c b/tests/unit/test_multiplication_opcode.c
index aba7f5660..fdb31c203 100644
--- a/tests/unit/test_multiplication_opcode.c
+++ b/tests/unit/test_multiplication_opcode.c
@@ -17,6 +17,7 @@
 #include "interpreter.h"
 #include "mem-allocator.h"
 #include "opcodes.h"
+#include "serializer.h"
 
 /**
  * Unit test's main function.
@@ -37,6 +38,12 @@ main( int __unused argc,
 
   mem_init();
 
+  const char *strings[] = { "a",
+                            "b" };
+  int nums [] = { 2 };
+  uint8_t offset = serializer_dump_strings( strings, 2);
+  serializer_dump_nums( nums, 1, offset, 2);
+
   init_int( test_program);
 
   return run_int() ? 0
diff --git a/tests/unit/test_remainder_opcode.c b/tests/unit/test_remainder_opcode.c
index 7e4882a5d..d9380fbc4 100644
--- a/tests/unit/test_remainder_opcode.c
+++ b/tests/unit/test_remainder_opcode.c
@@ -17,6 +17,7 @@
 #include "interpreter.h"
 #include "mem-allocator.h"
 #include "opcodes.h"
+#include "serializer.h"
 
 /**
  * Unit test's main function.
@@ -37,6 +38,12 @@ main( int __unused argc,
 
   mem_init();
 
+  const char *strings[] = { "a",
+                            "b" };
+  int nums [] = { 2 };
+  uint8_t offset = serializer_dump_strings( strings, 2);
+  serializer_dump_nums( nums, 1, offset, 2);
+
   init_int( test_program);
 
   return run_int() ? 0
diff --git a/tests/unit/test_substraction_opcode.c b/tests/unit/test_substraction_opcode.c
index 392f1bfb5..f47833de7 100644
--- a/tests/unit/test_substraction_opcode.c
+++ b/tests/unit/test_substraction_opcode.c
@@ -17,6 +17,7 @@
 #include "interpreter.h"
 #include "mem-allocator.h"
 #include "opcodes.h"
+#include "serializer.h"
 
 /**
  * Unit test's main function.
@@ -37,6 +38,12 @@ main( int __unused argc,
 
   mem_init();
 
+  const char *strings[] = { "a",
+                            "b" };
+  int nums [] = { 2 };
+  uint8_t offset = serializer_dump_strings( strings, 2);
+  serializer_dump_nums( nums, 1, offset, 2);
+
   init_int( test_program);
 
   return run_int() ? 0
diff --git a/tests/unit/test_var_decl_opcode_in_decl_lex_env.c b/tests/unit/test_var_decl_opcode_in_decl_lex_env.c
index a10ab2939..274ad6f77 100644
--- a/tests/unit/test_var_decl_opcode_in_decl_lex_env.c
+++ b/tests/unit/test_var_decl_opcode_in_decl_lex_env.c
@@ -17,6 +17,7 @@
 #include "interpreter.h"
 #include "mem-allocator.h"
 #include "opcodes.h"
+#include "serializer.h"
 
 /**
  * Unit test's main function.
@@ -35,6 +36,12 @@ main( int __unused argc,
 
   mem_init();
 
+  const char *strings[] = { "a",
+                            "b" };
+  int nums [] = { 2 };
+  uint8_t offset = serializer_dump_strings( strings, 2);
+  serializer_dump_nums( nums, 1, offset, 2);
+
   init_int( test_program);
 
   return run_int() ? 0