diff --git a/Makefile.mk b/Makefile.mk
index d6f2ce7ce..f2a73ce08 100644
--- a/Makefile.mk
+++ b/Makefile.mk
@@ -257,10 +257,7 @@ GIT_HASH=$(shell git rev-parse HEAD)
 BUILD_DATE=$(shell date +'%d/%m/%Y')
 
 CFLAGS_JERRY = $(CFLAGS_WARNINGS) $(CFLAGS_WERROR) $(CFLAGS_WFATAL_ERRORS)
-DEFINES_JERRY = -DMEM_HEAP_CHUNK_SIZE=$$((64)) -DMEM_HEAP_AREA_SIZE=$$((2 * 1024 + 512)) -DMEM_STATS \
-                -DCONFIG_ECMA_REFERENCE_COUNTER_WIDTH=$$((10)) \
-                -DCONFIG_MEM_STACK_LIMIT=$$((4 * 1024)) -DCONFIG_MEM_DATA_LIMIT_MINUS_HEAP_SIZE=$$((1024)) \
-                -DCONFIG_ECMA_NUMBER_FLOAT32
+DEFINES_JERRY = -DMEM_STATS
 
 DEFINES_JERRY += -DJERRY_BUILD_DATE="\"$(BUILD_DATE)\"" \
                  -DJERRY_COMMIT_HASH="\"$(GIT_HASH)\"" \
diff --git a/src/config.h b/src/config.h
new file mode 100644
index 000000000..fbfd0aeb0
--- /dev/null
+++ b/src/config.h
@@ -0,0 +1,88 @@
+/* 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 CONFIG_H
+#define CONFIG_H
+
+/**
+ * Limit of data (system heap, engine's data except engine's own heap)
+ */
+#define CONFIG_MEM_DATA_LIMIT_MINUS_HEAP_SIZE 1024
+
+/**
+ * Limit of stack size
+ */
+#define CONFIG_MEM_STACK_LIMIT 4096
+
+/**
+ * Log2 of maximum number of chunks in a pool
+ */
+#define CONFIG_MEM_POOL_MAX_CHUNKS_NUMBER_LOG 16
+
+/**
+ * Size of pool chunk
+ *
+ * Should not be less than size of any of ECMA Object Model's data types.
+ */
+#define CONFIG_MEM_POOL_CHUNK_SIZE 16
+
+/**
+ * Size of heap chunk
+ */
+#define CONFIG_MEM_HEAP_CHUNK_SIZE 64
+
+/**
+ * Size of heap
+ */
+#define CONFIG_MEM_HEAP_AREA_SIZE (2 * 1024 + 512)
+
+/**
+ * Log2 of maximum possible offset in the heap
+ *
+ * The option affects size of compressed pointer that in turn
+ * affects size of ECMA Object Model's data types.
+ *
+ * In any case size of any of the types should not exceed CONFIG_MEM_POOL_CHUNK_SIZE.
+ *
+ * On the other hand, value 2 ^ CONFIG_MEM_HEAP_OFFSET_LOG should not be less than CONFIG_MEM_HEAP_AREA_SIZE.
+ */
+#define CONFIG_MEM_HEAP_OFFSET_LOG 16
+
+/**
+ * Width of fields used for holding counter of references to ecma-strings and ecma-objects
+ *
+ * The option affects maximum number of simultaneously existing:
+ *  - references to one string;
+ *  - stack references to one object
+ * The number is ((2 ^ CONFIG_ECMA_REFERENCE_COUNTER_WIDTH) - 1).
+ *
+ * Also the option affects size of ECMA Object Model's data types.
+ * In any case size of any of the types should not exceed CONFIG_MEM_POOL_CHUNK_SIZE.
+ */
+#define CONFIG_ECMA_REFERENCE_COUNTER_WIDTH 10
+
+/**
+ * Use 32-bit/64-bit float for ecma-numbers
+ */
+#define CONFIG_ECMA_NUMBER_FLOAT32
+// #define CONFIG_ECMA_NUMBER_FLOAT64
+
+/**
+ * Use ASCII/UTF-16 representation for ecma-characters
+ */
+#define CONFIG_ECMA_CHAR_ASCII
+// #define CONFIG_ECMA_CHAR_UTF16
+
+#endif /* !CONFIG_H */
diff --git a/src/liballocator/mem-config.h b/src/liballocator/mem-config.h
index cf93d7c60..b27c4253e 100644
--- a/src/liballocator/mem-config.h
+++ b/src/liballocator/mem-config.h
@@ -16,20 +16,32 @@
 #ifndef MEM_CONFIG_H
 #define MEM_CONFIG_H
 
+#include "config.h"
+
 /**
  * Log2 of maximum possible offset in the heap
  */
-#define MEM_HEAP_OFFSET_LOG 16
+#define MEM_HEAP_OFFSET_LOG (CONFIG_MEM_HEAP_OFFSET_LOG)
 
 /**
- * Size of one pool chunk
+ * Size of heap
  */
-#define MEM_POOL_CHUNK_SIZE 16
+#define MEM_HEAP_AREA_SIZE (CONFIG_MEM_HEAP_AREA_SIZE)
+
+/**
+ * Size of heap chunk
+ */
+#define MEM_HEAP_CHUNK_SIZE (CONFIG_MEM_HEAP_CHUNK_SIZE)
+
+/**
+ * Size of pool chunk
+ */
+#define MEM_POOL_CHUNK_SIZE (CONFIG_MEM_POOL_CHUNK_SIZE)
 
 /**
  * Log2 of maximum number of chunks in a pool
  */
-#define MEM_POOL_MAX_CHUNKS_NUMBER_LOG 16
+#define MEM_POOL_MAX_CHUNKS_NUMBER_LOG (CONFIG_MEM_POOL_MAX_CHUNKS_NUMBER_LOG)
 
 /**
  * Logarithm of required alignment for allocated units/blocks
diff --git a/src/libecmaobjects/ecma-globals.h b/src/libecmaobjects/ecma-globals.h
index ee9b29664..7a218d511 100644
--- a/src/libecmaobjects/ecma-globals.h
+++ b/src/libecmaobjects/ecma-globals.h
@@ -21,8 +21,9 @@
  */
 
 #ifndef JERRY_ECMA_GLOBALS_H
-#define  JERRY_ECMA_GLOBALS_H
+#define JERRY_ECMA_GLOBALS_H
 
+#include "config.h"
 #include "globals.h"
 #include "mem-allocator.h"
 
@@ -442,15 +443,33 @@ typedef struct
   ecma_property_configurable_value_t configurable;
 } ecma_property_descriptor_t;
 
+#ifdef CONFIG_ECMA_CHAR_ASCII
 /**
  * Description of an ecma-character
  */
 typedef uint8_t ecma_char_t;
+#elif defined (CONFIG_ECMA_CHAR_UTF16)
+/**
+ * Description of an ecma-character
+ */
+typedef uint16_t ecma_char_t;
+#else /* !CONFIG_ECMA_CHAR_ASCII && !CONFIG_ECMA_CHAR_UTF16 */
+# error "!CONFIG_ECMA_CHAR_ASCII && !CONFIG_ECMA_CHAR_UTF16"
+#endif /* !CONFIG_ECMA_CHAR_ASCII && !CONFIG_ECMA_CHAR_UTF16 */
 
+#ifdef CONFIG_ECMA_NUMBER_FLOAT32
 /**
  * Description of an ecma-number
  */
 typedef float ecma_number_t;
+#elif defined (CONFIG_ECMA_NUMBER_FLOAT64)
+/**
+ * Description of an ecma-number
+ */
+typedef double ecma_number_t;
+#else /* !CONFIG_ECMA_NUMBER_FLOAT32 && !CONFIG_ECMA_NUMBER_FLOAT64 */
+#error "!CONFIG_ECMA_NUMBER_FLOAT32 && !CONFIG_ECMA_NUMBER_FLOAT64"
+#endif /* !CONFIG_ECMA_NUMBER_FLOAT32 && !CONFIG_ECMA_NUMBER_FLOAT64 */
 
 /**
  * Value '0' of ecma_number_t
diff --git a/src/libecmaobjects/ecma-helpers-number.c b/src/libecmaobjects/ecma-helpers-number.c
index c08dabdd1..0fe9f2855 100644
--- a/src/libecmaobjects/ecma-helpers-number.c
+++ b/src/libecmaobjects/ecma-helpers-number.c
@@ -284,7 +284,7 @@ ecma_number_get_fraction_and_exponent (ecma_number_t num, /**< ecma-number */
     /* IEEE-754 2008, 3.4, d */
     exponent = 1 - ecma_number_exponent_bias;
 
-    while (!(fraction & (1u << ECMA_NUMBER_FRACTION_WIDTH)))
+    while (!(fraction & (1ul << ECMA_NUMBER_FRACTION_WIDTH)))
     {
       JERRY_ASSERT (fraction != 0);
 
@@ -298,8 +298,8 @@ ecma_number_get_fraction_and_exponent (ecma_number_t num, /**< ecma-number */
     exponent = (int32_t) biased_exp - ecma_number_exponent_bias;
 
     JERRY_ASSERT (biased_exp > 0 && biased_exp < (1u << ECMA_NUMBER_BIASED_EXP_WIDTH) - 1);
-    JERRY_ASSERT ((fraction & (1u << ECMA_NUMBER_FRACTION_WIDTH)) == 0);
-    fraction |= 1u << ECMA_NUMBER_FRACTION_WIDTH;
+    JERRY_ASSERT ((fraction & (1ul << ECMA_NUMBER_FRACTION_WIDTH)) == 0);
+    fraction |= 1ul << ECMA_NUMBER_FRACTION_WIDTH;
   }
 
   *out_fraction_p = fraction;