diff --git a/jerry-core/ecma/base/ecma-globals.h b/jerry-core/ecma/base/ecma-globals.h
index 6d1c7721f7..f11cd06f01 100644
--- a/jerry-core/ecma/base/ecma-globals.h
+++ b/jerry-core/ecma/base/ecma-globals.h
@@ -579,6 +579,11 @@ typedef double ecma_number_t;
  */
 #define ECMA_NUMBER_HALF ((ecma_number_t) 0.5f)
 
+/**
+ * Value '-1' of ecma_number_t
+ */
+#define ECMA_NUMBER_MINUS_ONE ((ecma_number_t) -1)
+
 /**
  * Minimum positive and maximum value of ecma-number
  */
diff --git a/jerry-core/ecma/base/ecma-helpers-conversion.c b/jerry-core/ecma/base/ecma-helpers-conversion.c
index ae26385000..787155e4e2 100644
--- a/jerry-core/ecma/base/ecma-helpers-conversion.c
+++ b/jerry-core/ecma/base/ecma-helpers-conversion.c
@@ -1,4 +1,4 @@
-/* Copyright 2014-2015 Samsung Electronics Co., Ltd.
+/* Copyright 2014-2016 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.
@@ -404,7 +404,7 @@ ecma_utf8_string_to_number (const lit_utf8_byte_t *str_p, /**< utf-8 string */
     /* Hex literal handling */
     begin_p += 2;
 
-    ecma_number_t num = 0;
+    ecma_number_t num = ECMA_NUMBER_ZERO;
 
     for (const lit_utf8_byte_t * iter_p = begin_p;
          iter_p <= end_p;
@@ -796,7 +796,7 @@ ecma_uint32_to_utf8_string (uint32_t value, /**< value to convert */
     *p-- = digits[value % 10];
     value /= 10;
 
-    bytes_copied ++;
+    bytes_copied++;
   }
   while (value != 0);
 
@@ -821,9 +821,7 @@ ecma_uint32_to_utf8_string (uint32_t value, /**< value to convert */
 ecma_number_t
 ecma_uint32_to_number (uint32_t value) /**< unsigned 32-bit integer value */
 {
-  ecma_number_t num_value = (ecma_number_t) value;
-
-  return num_value;
+  return (ecma_number_t) value;
 } /* ecma_uint32_to_number */
 
 /**
@@ -834,9 +832,7 @@ ecma_uint32_to_number (uint32_t value) /**< unsigned 32-bit integer value */
 ecma_number_t
 ecma_int32_to_number (int32_t value) /**< signed 32-bit integer value */
 {
-  ecma_number_t num_value = (ecma_number_t) value;
-
-  return num_value;
+  return (ecma_number_t) value;
 } /* ecma_int32_to_number */
 
 /**
@@ -857,17 +853,8 @@ ecma_number_to_uint32 (ecma_number_t num) /**< ecma-number */
     return 0;
   }
 
-  bool sign = ecma_number_is_negative (num);
-  ecma_number_t abs_num;
-
-  if (sign)
-  {
-    abs_num = ecma_number_negate (num);
-  }
-  else
-  {
-    abs_num = num;
-  }
+  const bool sign = ecma_number_is_negative (num);
+  const ecma_number_t abs_num = sign ? ecma_number_negate (num) : num;
 
   // 2 ^ 32
   const uint64_t uint64_2_pow_32 = (1ull << 32);
@@ -890,16 +877,7 @@ ecma_number_to_uint32 (ecma_number_t num) /**< ecma-number */
   JERRY_ASSERT (num_in_uint32_range < uint64_2_pow_32);
   uint32_t uint32_num = (uint32_t) num_in_uint32_range;
 
-  uint32_t ret;
-
-  if (sign)
-  {
-    ret = -uint32_num;
-  }
-  else
-  {
-    ret = uint32_num;
-  }
+  const uint32_t ret = sign ? -uint32_num : uint32_num;
 
 #ifndef JERRY_NDEBUG
   if (sign
diff --git a/jerry-core/ecma/base/ecma-helpers-number.c b/jerry-core/ecma/base/ecma-helpers-number.c
index 5ba16a7864..80085c8fbe 100644
--- a/jerry-core/ecma/base/ecma-helpers-number.c
+++ b/jerry-core/ecma/base/ecma-helpers-number.c
@@ -1,5 +1,5 @@
-/* Copyright 2014 Samsung Electronics Co., Ltd.
- * Copyright 2015 University of Szeged.
+/* Copyright 2014-2016 Samsung Electronics Co., Ltd.
+ * Copyright 2015-2016 University of Szeged.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -24,6 +24,9 @@
 #include "ecma-globals.h"
 #include "ecma-helpers.h"
 
+#define ECMA_NUMBER_SIGN_POS (ECMA_NUMBER_FRACTION_WIDTH + \
+                              ECMA_NUMBER_BIASED_EXP_WIDTH)
+
 #if CONFIG_ECMA_NUMBER_TYPE == CONFIG_ECMA_NUMBER_FLOAT32
 JERRY_STATIC_ASSERT (sizeof (ecma_number_t) == sizeof (uint32_t),
                      size_of_ecma_number_t_must_be_equal_to_4_bytes);
@@ -38,16 +41,12 @@ ecma_number_pack (bool sign, /**< sign */
                   uint32_t biased_exp, /**< biased exponent */
                   uint64_t fraction) /**< fraction */
 {
-  const uint32_t fraction_pos = 0;
-  const uint32_t biased_exp_pos = fraction_pos + ECMA_NUMBER_FRACTION_WIDTH;
-  const uint32_t sign_pos = biased_exp_pos + ECMA_NUMBER_BIASED_EXP_WIDTH;
-
   JERRY_ASSERT ((biased_exp & ~((1u << ECMA_NUMBER_BIASED_EXP_WIDTH) - 1)) == 0);
   JERRY_ASSERT ((fraction & ~((1ull << ECMA_NUMBER_FRACTION_WIDTH) - 1)) == 0);
 
-  uint32_t packed_value = (((sign ? 1u : 0u) << sign_pos) |
-                           (biased_exp << biased_exp_pos) |
-                           (((uint32_t) fraction) << fraction_pos));
+  uint32_t packed_value = (((sign ? 1u : 0u) << ECMA_NUMBER_SIGN_POS) |
+                           (biased_exp << ECMA_NUMBER_FRACTION_WIDTH) |
+                           ((uint32_t) fraction));
 
   union
   {
@@ -69,10 +68,6 @@ ecma_number_unpack (ecma_number_t num, /**< ecma-number */
                     uint32_t *biased_exp_p, /**< [out] biased exponent (optional) */
                     uint64_t *fraction_p) /**< [out] fraction (optional) */
 {
-  const uint32_t fraction_pos = 0;
-  const uint32_t biased_exp_pos = fraction_pos + ECMA_NUMBER_FRACTION_WIDTH;
-  const uint32_t sign_pos = biased_exp_pos + ECMA_NUMBER_BIASED_EXP_WIDTH;
-
   union
   {
     uint32_t u32_value;
@@ -85,12 +80,12 @@ ecma_number_unpack (ecma_number_t num, /**< ecma-number */
 
   if (sign_p != NULL)
   {
-    *sign_p = ((packed_value >> sign_pos) != 0);
+    *sign_p = ((packed_value >> ECMA_NUMBER_SIGN_POS) != 0);
   }
 
   if (biased_exp_p != NULL)
   {
-    *biased_exp_p = (((packed_value) & ~(1u << sign_pos)) >> biased_exp_pos);
+    *biased_exp_p = (((packed_value) & ~(1u << ECMA_NUMBER_SIGN_POS)) >> ECMA_NUMBER_FRACTION_WIDTH);
   }
 
   if (fraction_p != NULL)
@@ -107,10 +102,6 @@ ecma_number_unpack (ecma_number_t num, /**< ecma-number */
  */
 const int32_t ecma_number_exponent_bias = 127;
 
-/**
- * Relative precision used in calculation with ecma-numbers
- */
-const ecma_number_t ecma_number_relative_eps = 1.0e-10f;
 #elif CONFIG_ECMA_NUMBER_TYPE == CONFIG_ECMA_NUMBER_FLOAT64
 JERRY_STATIC_ASSERT (sizeof (ecma_number_t) == sizeof (uint64_t),
                      size_of_ecma_number_t_must_be_equal_to_8_bytes);
@@ -125,13 +116,9 @@ ecma_number_pack (bool sign, /**< sign */
                   uint32_t biased_exp, /**< biased exponent */
                   uint64_t fraction) /**< fraction */
 {
-  const uint32_t fraction_pos = 0;
-  const uint32_t biased_exp_pos = fraction_pos + ECMA_NUMBER_FRACTION_WIDTH;
-  const uint32_t sign_pos = biased_exp_pos + ECMA_NUMBER_BIASED_EXP_WIDTH;
-
-  uint64_t packed_value = (((sign ? 1ull : 0ull) << sign_pos) |
-                           (((uint64_t) biased_exp) << biased_exp_pos) |
-                           (fraction << fraction_pos));
+  uint64_t packed_value = (((sign ? 1ull : 0ull) << ECMA_NUMBER_SIGN_POS) |
+                           (((uint64_t) biased_exp) << ECMA_NUMBER_FRACTION_WIDTH) |
+                           fraction);
 
   JERRY_ASSERT ((biased_exp & ~((1u << ECMA_NUMBER_BIASED_EXP_WIDTH) - 1)) == 0);
   JERRY_ASSERT ((fraction & ~((1ull << ECMA_NUMBER_FRACTION_WIDTH) - 1)) == 0);
@@ -156,10 +143,6 @@ ecma_number_unpack (ecma_number_t num, /**< ecma-number */
                     uint32_t *biased_exp_p, /**< [out] biased exponent (optional) */
                     uint64_t *fraction_p) /**< [out] fraction (optional) */
 {
-  const uint32_t fraction_pos = 0;
-  const uint32_t biased_exp_pos = fraction_pos + ECMA_NUMBER_FRACTION_WIDTH;
-  const uint32_t sign_pos = biased_exp_pos + ECMA_NUMBER_BIASED_EXP_WIDTH;
-
   union
   {
     uint64_t u64_value;
@@ -171,12 +154,12 @@ ecma_number_unpack (ecma_number_t num, /**< ecma-number */
 
   if (sign_p != NULL)
   {
-    *sign_p = ((packed_value >> sign_pos) != 0);
+    *sign_p = ((packed_value >> ECMA_NUMBER_SIGN_POS) != 0);
   }
 
   if (biased_exp_p != NULL)
   {
-    *biased_exp_p = (uint32_t) (((packed_value) & ~(1ull << sign_pos)) >> biased_exp_pos);
+    *biased_exp_p = (uint32_t) (((packed_value) & ~(1ull << ECMA_NUMBER_SIGN_POS)) >> ECMA_NUMBER_FRACTION_WIDTH);
   }
 
   if (fraction_p != NULL)
@@ -193,10 +176,6 @@ ecma_number_unpack (ecma_number_t num, /**< ecma-number */
  */
 const int32_t ecma_number_exponent_bias = 1023;
 
-/**
- * Relative precision used in calculation with ecma-numbers
- */
-const ecma_number_t ecma_number_relative_eps = 1.0e-16;
 #endif /* CONFIG_ECMA_NUMBER_TYPE == CONFIG_ECMA_NUMBER_FLOAT64 */
 
 /**
@@ -638,7 +617,7 @@ ecma_number_trunc (ecma_number_t num) /**< ecma-number */
 
   if (exponent < 0)
   {
-    return 0;
+    return ECMA_NUMBER_ZERO;
   }
   else if (exponent < dot_shift)
   {
@@ -674,21 +653,18 @@ ecma_number_t
 ecma_number_calc_remainder (ecma_number_t left_num, /**< left operand */
                             ecma_number_t right_num) /**< right operand */
 {
-  ecma_number_t n = left_num, d = right_num;
-
-  JERRY_ASSERT (!ecma_number_is_nan (n)
-                && !ecma_number_is_zero (n)
-                && !ecma_number_is_infinity (n));
-  JERRY_ASSERT (!ecma_number_is_nan (d)
-                && !ecma_number_is_zero (d)
-                && !ecma_number_is_infinity (d));
-
-  ecma_number_t q = ecma_number_trunc (ecma_number_divide (n, d));
+  JERRY_ASSERT (!ecma_number_is_nan (left_num)
+                && !ecma_number_is_zero (left_num)
+                && !ecma_number_is_infinity (left_num));
+  JERRY_ASSERT (!ecma_number_is_nan (right_num)
+                && !ecma_number_is_zero (right_num)
+                && !ecma_number_is_infinity (right_num));
 
-  ecma_number_t r = ecma_number_substract (n, ecma_number_multiply (d, q));
+  const ecma_number_t q = ecma_number_trunc (ecma_number_divide (left_num, right_num));
+  ecma_number_t r = ecma_number_substract (left_num, ecma_number_multiply (right_num, q));
 
   if (ecma_number_is_zero (r)
-      && ecma_number_is_negative (n))
+      && ecma_number_is_negative (left_num))
   {
     r = ecma_number_negate (r);
   }
diff --git a/jerry-core/ecma/base/ecma-helpers-string.c b/jerry-core/ecma/base/ecma-helpers-string.c
index fe420909c1..acc468cfba 100644
--- a/jerry-core/ecma/base/ecma-helpers-string.c
+++ b/jerry-core/ecma/base/ecma-helpers-string.c
@@ -339,17 +339,16 @@ ecma_concat_ecma_strings (ecma_string_t *string1_p, /**< first ecma-string */
 
   const size_t data_size = new_size + sizeof (ecma_string_heap_header_t);
   ecma_string_heap_header_t *data_p = (ecma_string_heap_header_t *) mem_heap_alloc_block (data_size);
-  ssize_t bytes_copied1, bytes_copied2;
 
-  bytes_copied1 = ecma_string_to_utf8_string (string1_p,
-                                              (lit_utf8_byte_t *) (data_p + 1),
-                                              (ssize_t) str1_size);
-  JERRY_ASSERT (bytes_copied1 > 0);
+  ssize_t bytes_copied = ecma_string_to_utf8_string (string1_p,
+                                                     (lit_utf8_byte_t *) (data_p + 1),
+                                                     (ssize_t) str1_size);
+  JERRY_ASSERT (bytes_copied > 0);
 
-  bytes_copied2 = ecma_string_to_utf8_string (string2_p,
-                                              (lit_utf8_byte_t *) (data_p + 1) + str1_size,
-                                              (ssize_t) str2_size);
-  JERRY_ASSERT (bytes_copied2 > 0);
+  bytes_copied = ecma_string_to_utf8_string (string2_p,
+                                             (lit_utf8_byte_t *) (data_p + 1) + str1_size,
+                                             (ssize_t) str2_size);
+  JERRY_ASSERT (bytes_copied > 0);
 
   data_p->size = (uint16_t) new_size;
   data_p->length = (uint16_t) (ecma_string_get_length (string1_p) + ecma_string_get_length (string2_p));
@@ -469,8 +468,8 @@ ecma_copy_or_ref_ecma_string (ecma_string_t *string_desc_p) /**< string descript
 } /* ecma_copy_or_ref_ecma_string */
 
 /**
- * Decrease reference counter and deallocate ecma-string if
- * after that the counter the counter becomes zero.
+ * Decrease reference counter and deallocate ecma-string
+ * if the counter becomes zero.
  */
 void
 ecma_deref_ecma_string (ecma_string_t *string_p) /**< ecma-string */
@@ -518,32 +517,6 @@ ecma_deref_ecma_string (ecma_string_t *string_p) /**< ecma-string */
   ecma_dealloc_string (string_p);
 } /* ecma_deref_ecma_string */
 
-/**
- * Assertion that specified ecma-string need not be freed
- */
-void
-ecma_check_that_ecma_string_need_not_be_freed (const ecma_string_t *string_p) /**< ecma-string descriptor */
-{
-#ifdef JERRY_NDEBUG
-  (void) string_p;
-#else /* JERRY_NDEBUG */
-
-  /*
-   * No reference counter increment or decrement
-   * should be performed with ecma-string placed
-   * on stack
-   */
-  JERRY_ASSERT (string_p->refs == 1);
-
-  ecma_string_container_t container_type = (ecma_string_container_t) string_p->container;
-
-  JERRY_ASSERT (container_type == ECMA_STRING_CONTAINER_LIT_TABLE ||
-                container_type == ECMA_STRING_CONTAINER_MAGIC_STRING ||
-                container_type == ECMA_STRING_CONTAINER_MAGIC_STRING_EX ||
-                container_type == ECMA_STRING_CONTAINER_UINT32_IN_DESC);
-#endif /* !JERRY_NDEBUG */
-} /* ecma_check_that_ecma_string_need_not_be_freed */
-
 /**
  * Convert ecma-string to number
  */
@@ -926,16 +899,12 @@ ecma_compare_ecma_strings (const ecma_string_t *string1_p, /* ecma-string */
 {
   JERRY_ASSERT (string1_p != NULL && string2_p != NULL);
 
-  const bool is_equal_hashes = (string1_p->hash == string2_p->hash);
-
-  if (!is_equal_hashes)
+  if (string1_p->hash != string2_p->hash)
   {
     return false;
   }
-  const bool is_equal_containers = (string1_p->container == string2_p->container);
-  const bool is_equal_fields = (string1_p->u.common_field == string2_p->u.common_field);
 
-  if (is_equal_containers && is_equal_fields)
+  if (ecma_compare_ecma_strings_equal_hashes (string1_p, string2_p))
   {
     return true;
   }
diff --git a/jerry-core/ecma/base/ecma-helpers.h b/jerry-core/ecma/base/ecma-helpers.h
index 3b015cd563..2e602552e1 100644
--- a/jerry-core/ecma/base/ecma-helpers.h
+++ b/jerry-core/ecma/base/ecma-helpers.h
@@ -95,7 +95,6 @@ extern ecma_string_t *ecma_new_ecma_string_from_magic_string_ex_id (lit_magic_st
 extern ecma_string_t *ecma_concat_ecma_strings (ecma_string_t *, ecma_string_t *);
 extern ecma_string_t *ecma_copy_or_ref_ecma_string (ecma_string_t *);
 extern void ecma_deref_ecma_string (ecma_string_t *);
-extern void ecma_check_that_ecma_string_need_not_be_freed (const ecma_string_t *);
 extern ecma_number_t ecma_string_to_number (const ecma_string_t *);
 extern bool ecma_string_get_array_index (const ecma_string_t *, uint32_t *);
 
@@ -120,8 +119,6 @@ extern ecma_string_t *ecma_string_substr (const ecma_string_t *, ecma_length_t,
 extern ecma_string_t *ecma_string_trim (const ecma_string_t *);
 
 /* ecma-helpers-number.c */
-extern const ecma_number_t ecma_number_relative_eps;
-
 extern ecma_number_t ecma_number_make_nan (void);
 extern ecma_number_t ecma_number_make_infinity (bool);
 extern bool ecma_number_is_nan (ecma_number_t);
diff --git a/jerry-core/ecma/builtin-objects/ecma-builtin-array-prototype.c b/jerry-core/ecma/builtin-objects/ecma-builtin-array-prototype.c
index 13192c84e3..54d5beebdd 100644
--- a/jerry-core/ecma/builtin-objects/ecma-builtin-array-prototype.c
+++ b/jerry-core/ecma/builtin-objects/ecma-builtin-array-prototype.c
@@ -961,18 +961,18 @@ ecma_builtin_array_prototype_object_sort_compare_helper (ecma_value_t j, /**< le
   {
     if (k_is_undef)
     {
-      *result_p = ecma_int32_to_number (0);
+      *result_p = ECMA_NUMBER_ZERO;
     }
     else
     {
-      *result_p = ecma_int32_to_number (1);
+      *result_p = ECMA_NUMBER_ONE;
     }
   }
   else
   {
     if (k_is_undef)
     {
-      *result_p = ecma_int32_to_number (-1);
+      *result_p = ECMA_NUMBER_MINUS_ONE;
     }
     else
     {
@@ -986,15 +986,15 @@ ecma_builtin_array_prototype_object_sort_compare_helper (ecma_value_t j, /**< le
 
         if (ecma_compare_ecma_strings_relational (j_str_p, k_str_p))
         {
-          *result_p = ecma_int32_to_number (-1);
+          *result_p = ECMA_NUMBER_MINUS_ONE;
         }
         else if (!ecma_compare_ecma_strings (j_str_p, k_str_p))
         {
-          *result_p = ecma_int32_to_number (1);
+          *result_p = ECMA_NUMBER_ONE;
         }
         else
         {
-          *result_p = ecma_int32_to_number (0);
+          *result_p = ECMA_NUMBER_ZERO;
         }
 
         ECMA_FINALIZE (k_value);
@@ -1766,7 +1766,7 @@ ecma_builtin_array_prototype_object_index_of (ecma_value_t this_arg, /**< this a
   if (len == 0)
   {
     ecma_number_t *num_p = ecma_alloc_number ();
-    *num_p = ecma_int32_to_number (-1);
+    *num_p = ECMA_NUMBER_MINUS_ONE;
     ret_value = ecma_make_number_value (num_p);
   }
   else
@@ -1774,7 +1774,7 @@ ecma_builtin_array_prototype_object_index_of (ecma_value_t this_arg, /**< this a
     /* 5. */
     ECMA_OP_TO_NUMBER_TRY_CATCH (arg_from_idx, arg2, ret_value);
 
-    ecma_number_t found_index = ecma_int32_to_number (-1);
+    ecma_number_t found_index = ECMA_NUMBER_MINUS_ONE;
 
     uint32_t from_idx = ecma_builtin_helper_array_index_normalize (arg_from_idx, len);
 
@@ -1863,7 +1863,7 @@ ecma_builtin_array_prototype_object_last_index_of (ecma_value_t this_arg, /**< t
   uint32_t len = ecma_number_to_uint32 (len_number);
 
   ecma_number_t *num_p = ecma_alloc_number ();
-  *num_p = ecma_int32_to_number (-1);
+  *num_p = ECMA_NUMBER_MINUS_ONE;
 
   /* 4. */
   if (len == 0)
diff --git a/jerry-core/ecma/builtin-objects/ecma-builtin-helpers.c b/jerry-core/ecma/builtin-objects/ecma-builtin-helpers.c
index 6900e7f0aa..c7b9b72efb 100644
--- a/jerry-core/ecma/builtin-objects/ecma-builtin-helpers.c
+++ b/jerry-core/ecma/builtin-objects/ecma-builtin-helpers.c
@@ -523,7 +523,7 @@ ecma_builtin_helper_string_prototype_object_index_of (ecma_value_t this_arg, /**
   ecma_string_t *search_str_p = ecma_get_string_from_value (search_str_val);
 
   ecma_number_t *ret_num_p = ecma_alloc_number ();
-  *ret_num_p = ecma_int32_to_number (-1);
+  *ret_num_p = ECMA_NUMBER_MINUS_ONE;
 
   /* 8 (indexOf) -- 9 (lastIndexOf) */
   ecma_length_t index_of = 0;
diff --git a/jerry-core/ecma/builtin-objects/ecma-builtin-math.c b/jerry-core/ecma/builtin-objects/ecma-builtin-math.c
index 78af37540c..2e397e406c 100644
--- a/jerry-core/ecma/builtin-objects/ecma-builtin-math.c
+++ b/jerry-core/ecma/builtin-objects/ecma-builtin-math.c
@@ -1,4 +1,4 @@
-/* Copyright 2014-2015 Samsung Electronics Co., Ltd.
+/* Copyright 2014-2016 Samsung Electronics Co., Ltd.
  * Copyright 2015-2016 University of Szeged.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
@@ -572,16 +572,16 @@ ecma_builtin_math_object_round (ecma_value_t this_arg __attr_unused___, /**< 'th
     *num_p = arg_num;
   }
   else if (ecma_number_is_negative (arg_num)
-           && arg_num >= -0.5f)
+           && arg_num >= -ECMA_NUMBER_HALF)
   {
-    *num_p = ecma_number_negate (0.0f);
+    *num_p = ecma_number_negate (ECMA_NUMBER_ZERO);
   }
   else
   {
-    const ecma_number_t up_half = arg_num + 0.5f;
-    const ecma_number_t down_half = arg_num - 0.5f;
-    const ecma_number_t up_rounded = up_half - ecma_op_number_remainder (up_half, 1);
-    const ecma_number_t down_rounded = down_half - ecma_op_number_remainder (down_half, 1);
+    const ecma_number_t up_half = arg_num + ECMA_NUMBER_HALF;
+    const ecma_number_t down_half = arg_num - ECMA_NUMBER_HALF;
+    const ecma_number_t up_rounded = up_half - ecma_op_number_remainder (up_half, ECMA_NUMBER_ONE);
+    const ecma_number_t down_rounded = down_half - ecma_op_number_remainder (down_half, ECMA_NUMBER_ONE);
 
     if (up_rounded - arg_num <= arg_num - down_rounded)
     {
diff --git a/jerry-core/ecma/builtin-objects/ecma-builtin-string-prototype.c b/jerry-core/ecma/builtin-objects/ecma-builtin-string-prototype.c
index b34b1417f8..0b12329341 100644
--- a/jerry-core/ecma/builtin-objects/ecma-builtin-string-prototype.c
+++ b/jerry-core/ecma/builtin-objects/ecma-builtin-string-prototype.c
@@ -1,4 +1,4 @@
-/* Copyright 2014-2015 Samsung Electronics Co., Ltd.
+/* Copyright 2014-2016 Samsung Electronics Co., Ltd.
  * Copyright 2015-2016 University of Szeged.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
@@ -367,15 +367,15 @@ ecma_builtin_string_prototype_object_locale_compare (ecma_value_t this_arg, /**<
 
   if (ecma_compare_ecma_strings_relational (this_string_p, arg_string_p))
   {
-    *result_p = ecma_int32_to_number (-1);
+    *result_p = ECMA_NUMBER_MINUS_ONE;
   }
   else if (!ecma_compare_ecma_strings (this_string_p, arg_string_p))
   {
-    *result_p = ecma_int32_to_number (1);
+    *result_p = ECMA_NUMBER_ONE;
   }
   else
   {
-    *result_p = ecma_int32_to_number (0);
+    *result_p = ECMA_NUMBER_ZERO;
   }
 
   ret_value = ecma_make_number_value (result_p);
diff --git a/jerry-core/ecma/operations/ecma-array-object.c b/jerry-core/ecma/operations/ecma-array-object.c
index 00898924bc..ced60db0e0 100644
--- a/jerry-core/ecma/operations/ecma-array-object.c
+++ b/jerry-core/ecma/operations/ecma-array-object.c
@@ -1,4 +1,4 @@
-/* Copyright 2014-2015 Samsung Electronics Co., Ltd.
+/* Copyright 2014-2016 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.
@@ -179,8 +179,6 @@ ecma_op_array_object_define_own_property (ecma_object_t *obj_p, /**< the array o
       return ecma_op_general_object_define_own_property (obj_p, property_name_p, property_desc_p, is_throw);
     }
 
-    ecma_number_t new_len_num;
-
     // c.
     ecma_value_t completion = ecma_op_to_number (property_desc_p->value);
     if (ecma_is_value_error (completion))
@@ -191,7 +189,7 @@ ecma_op_array_object_define_own_property (ecma_object_t *obj_p, /**< the array o
     JERRY_ASSERT (!ecma_is_value_error (completion)
                   && ecma_is_value_number (completion));
 
-    new_len_num = *ecma_get_number_from_value (completion);
+    ecma_number_t new_len_num = *ecma_get_number_from_value (completion);
 
     ecma_free_value (completion);
 
diff --git a/jerry-core/ecma/operations/ecma-number-arithmetic.c b/jerry-core/ecma/operations/ecma-number-arithmetic.c
index 5e517cbafa..d61d4efe75 100644
--- a/jerry-core/ecma/operations/ecma-number-arithmetic.c
+++ b/jerry-core/ecma/operations/ecma-number-arithmetic.c
@@ -1,4 +1,4 @@
-/* Copyright 2014 Samsung Electronics Co., Ltd.
+/* Copyright 2014-2016 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.
@@ -38,23 +38,21 @@ ecma_number_t
 ecma_op_number_remainder (ecma_number_t left_num, /**< left operand */
                           ecma_number_t right_num) /**< right operand */
 {
-  ecma_number_t n = left_num, d = right_num;
-
-  if (ecma_number_is_nan (n)
-      || ecma_number_is_nan (d)
-      || ecma_number_is_infinity (n)
-      || ecma_number_is_zero (d))
+  if (ecma_number_is_nan (left_num)
+      || ecma_number_is_nan (right_num)
+      || ecma_number_is_infinity (left_num)
+      || ecma_number_is_zero (right_num))
   {
     return ecma_number_make_nan ();
   }
-  else if (ecma_number_is_infinity (d)
-           || (ecma_number_is_zero (n)
-               && !ecma_number_is_zero (d)))
+  else if (ecma_number_is_infinity (right_num)
+           || (ecma_number_is_zero (left_num)
+               && !ecma_number_is_zero (right_num)))
   {
-    return n;
+    return left_num;
   }
 
-  return ecma_number_calc_remainder (n, d);
+  return ecma_number_calc_remainder (left_num, right_num);
 } /* ecma_op_number_remainder */
 
 /**
diff --git a/jerry-core/parser/js/js-lexer.c b/jerry-core/parser/js/js-lexer.c
index fc0e7cc41d..b9517d324e 100644
--- a/jerry-core/parser/js/js-lexer.c
+++ b/jerry-core/parser/js/js-lexer.c
@@ -792,7 +792,7 @@ lexer_parse_number (parser_context_t *context_p) /**< context */
 
       do
       {
-        source_p ++;
+        source_p++;
       }
       while (source_p < source_end_p
              && lexer_is_hex_digit (source_p[0]));
@@ -809,7 +809,7 @@ lexer_parse_number (parser_context_t *context_p) /**< context */
 
       do
       {
-        source_p ++;
+        source_p++;
       }
       while (source_p < source_end_p
              && source_p[0] >= '0'
diff --git a/jerry-core/parser/js/js-parser.c b/jerry-core/parser/js/js-parser.c
index 3f4222b3be..7b664a5698 100644
--- a/jerry-core/parser/js/js-parser.c
+++ b/jerry-core/parser/js/js-parser.c
@@ -1430,7 +1430,7 @@ parser_post_processing (parser_context_t *context_p) /**< context */
          * instructions, since this form is constructed during post
          * processing and cannot be emitted directly. */
         *opcode_p = CBC_JUMP_FORWARD;
-        length --;
+        length--;
       }
       else
       {
diff --git a/jerry-core/vm/vm.c b/jerry-core/vm/vm.c
index c65c4b208c..1d2ce090e6 100644
--- a/jerry-core/vm/vm.c
+++ b/jerry-core/vm/vm.c
@@ -1121,7 +1121,7 @@ vm_loop (vm_frame_ctx_t *frame_ctx_p) /**< frame context */
           if (base & 0x2)
           {
             /* For decrement operators */
-            increase = -ECMA_NUMBER_ONE;
+            increase = ECMA_NUMBER_MINUS_ONE;
           }
 
           /* Post operators require the unmodifed number value. */
@@ -2290,7 +2290,7 @@ vm_execute (vm_frame_ctx_t *frame_ctx_p, /**< frame context */
   else
   {
     ecma_value_t *src_p = (ecma_value_t *) arg_p;
-    arg_list_len --;
+    arg_list_len--;
 
     if (arg_list_len > argument_end)
     {