diff --git a/Makefile b/Makefile
index 6b7d69ddf..a9a168147 100644
--- a/Makefile
+++ b/Makefile
@@ -31,7 +31,7 @@ SUP_STM32F4 = ./third-party/STM32F4-Discovery_FW_V1.1.0/Libraries/CMSIS/ST/STM32
 #  Add common-io.c and sensors.c
 SOURCES = \
 	$(sort \
-	$(wildcard ./src/jerry-libc.c ./src/pretty-printer.c) \
+	$(wildcard ./src/libruntime/*.c) \
 	$(wildcard ./src/libperipherals/actuators.c) \
 	$(wildcard ./src/libjsparser/*.c) \
 	$(wildcard ./src/libecmaobjects/*.c) \
@@ -40,11 +40,16 @@ SOURCES = \
 	$(wildcard ./src/libcoreint/*.c) )
 
 SOURCES_STM32F4 = \
-	third-party/STM32F4-Discovery_FW_V1.1.0/Libraries/CMSIS/ST/STM32F4xx/Source/Templates/system_stm32f4xx.c
+	third-party/STM32F4-Discovery_FW_V1.1.0/Libraries/CMSIS/ST/STM32F4xx/Source/Templates/system_stm32f4xx.c \
+        $(wildcard src/libruntime/stm32f4/*)
+
+SOURCES_LINUX = \
+        $(wildcard src/libruntime/linux/*)
 
 HEADERS = \
 	$(sort \
 	$(wildcard ./src/*.h) \
+	$(wildcard ./src/libruntime/*.h) \
 	$(wildcard ./src/libperipherals/*.h) \
 	$(wildcard ./src/libjsparser/*.h) \
 	$(wildcard ./src/libecmaobjects/*.h) \
@@ -54,6 +59,7 @@ HEADERS = \
 
 INCLUDES = \
 	-I src \
+	-I src/libruntime \
 	-I src/libperipherals \
 	-I src/libjsparser \
 	-I src/libecmaobjects \
@@ -129,12 +135,12 @@ debug.stdm32f4.bin: debug.stdm32f4.elf
 debug: clean
 	mkdir -p $(OUT_DIR)/debug.host/
 	$(CC) $(CFLAGS) $(DEBUG_OPTIONS) $(DEFINES) $(TARGET_HOST) \
-	$(SOURCES) $(MAIN_MODULE_SRC) -o $(OUT_DIR)/debug.host/$(TARGET)
+	$(SOURCES) $(SOURCES_LINUX) $(MAIN_MODULE_SRC) -o $(OUT_DIR)/debug.host/$(TARGET)
 
 release: clean
 	mkdir -p $(OUT_DIR)/release.host/
 	$(CC) $(CFLAGS) $(RELEASE_OPTIONS) $(DEFINES) $(TARGET_HOST) \
-	$(SOURCES) $(MAIN_MODULE_SRC) -o $(OUT_DIR)/release.host/$(TARGET)
+	$(SOURCES) $(SOURCES_LINUX) $(MAIN_MODULE_SRC) -o $(OUT_DIR)/release.host/$(TARGET)
 	$(STRIP) $(OUT_DIR)/release.host/$(TARGET)
 
 tests:
@@ -142,7 +148,7 @@ tests:
 	for unit_test in $(UNITTESTS); \
 	do \
 		$(CC) -O3 $(CFLAGS) $(DEBUG_OPTIONS) $(DEFINES) $(TARGET_HOST) \
-		$(SOURCES) $(UNITTESTS_SRC_DIR)/"$$unit_test".c -o $(OUT_DIR)/tests.host/"$$unit_test"; \
+		$(SOURCES) $(SOURCES_LINUX) $(UNITTESTS_SRC_DIR)/"$$unit_test".c -o $(OUT_DIR)/tests.host/"$$unit_test"; \
 	done
 
 clean:
diff --git a/src/globals.h b/src/globals.h
index 601af677e..c70b1beb5 100644
--- a/src/globals.h
+++ b/src/globals.h
@@ -16,7 +16,6 @@
 #ifndef JERRY_GLOBALS_H
 #define JERRY_GLOBALS_H
 
-#include <assert.h>
 #include <stddef.h>
 #include <stdbool.h>
 
@@ -38,6 +37,7 @@ typedef signed int int32_t;
  */
 #define __unused __attribute__((unused))
 #define __packed __attribute__((packed))
+#define __noreturn __attribute__((noreturn))
 
 /**
  * Constants
@@ -68,8 +68,10 @@ typedef signed int int32_t;
  */
 extern uint32_t jerry_UnreferencedExpression;
 
+extern void __noreturn jerry_AssertFail( const char *assertion, const char *file, const uint32_t line);
+
 #ifndef JERRY_NDEBUG
-#define JERRY_ASSERT( x ) assert( x )
+#define JERRY_ASSERT( x ) do { if ( __builtin_expect( !( x ), 0 ) ) { jerry_AssertFail( #x, __FILE__, __LINE__); } } while(0)
 #else /* !JERRY_NDEBUG */
 #define JERRY_ASSERT( x ) (void) (x)
 #endif /* !JERRY_NDEBUG */
diff --git a/src/libjsparser/mappings.h b/src/libjsparser/mappings.h
index 6536bca0e..ffcbc76f1 100644
--- a/src/libjsparser/mappings.h
+++ b/src/libjsparser/mappings.h
@@ -17,7 +17,7 @@
 #define MAPPINGS_H
 
 #ifndef __HOST
-#include "../jerry-libc.h"
+#include "jerry-libc.h"
 #include "allocator.h"
 #include <stdarg.h>
 
diff --git a/src/jerry-libc.c b/src/libruntime/jerry-libc.c
similarity index 97%
rename from src/jerry-libc.c
rename to src/libruntime/jerry-libc.c
index f8b599a88..94922f0b8 100644
--- a/src/jerry-libc.c
+++ b/src/libruntime/jerry-libc.c
@@ -22,6 +22,7 @@
 #include <stdarg.h>
 
 extern int vprintf (__const char *__restrict __format, __builtin_va_list __arg);
+extern void __noreturn exit(int status);
 
 /**
  * memset
@@ -115,12 +116,11 @@ __putchar (int c)
   return __printf ("%c", c);
 }
 
-/** exit - cause normal process termination. Infinite loop.  */
-void
-__exit (int status __unused)
+/** exit - cause normal process termination  */
+void __noreturn
+__exit (int status)
 {
-  for (;;)
-    ;
+  exit( status);
 }
 
 /** Compare two strings. return an integer less than, equal to, or greater than zero 
diff --git a/src/jerry-libc.h b/src/libruntime/jerry-libc.h
similarity index 97%
rename from src/jerry-libc.h
rename to src/libruntime/jerry-libc.h
index 09619e95f..9834e24ef 100644
--- a/src/jerry-libc.h
+++ b/src/libruntime/jerry-libc.h
@@ -26,7 +26,7 @@ extern int __memcmp (const void *s1, const void *s2, size_t n);
 extern void *__memcpy (void *s1, const void *s2, size_t n);
 extern int __printf (const char *format, ...);
 extern int __putchar (int);
-extern void __exit (int);
+extern void __noreturn __exit (int);
 
 extern int __strcmp (const char *, const char *);
 extern int __strncmp (const char *, const char *, size_t);
diff --git a/src/libruntime/linux/jerry-assert.c b/src/libruntime/linux/jerry-assert.c
new file mode 100644
index 000000000..c947f3b21
--- /dev/null
+++ b/src/libruntime/linux/jerry-assert.c
@@ -0,0 +1,31 @@
+/* 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.
+ */
+
+#include "globals.h"
+#include "jerry-libc.h"
+
+/**
+ * Handle failed assertion
+ */
+void __noreturn
+jerry_AssertFail( const char *assertion, /**< assertion condition string */
+		  const char *file, /**< file name */
+                  const uint32_t line) /** line */
+{
+  __printf("Assertion '%s' failed at %s:%u\n",
+           assertion, file, line);
+
+  __exit( 1);
+} /* jerry_AssertFail */
diff --git a/src/pretty-printer.c b/src/libruntime/pretty-printer.c
similarity index 100%
rename from src/pretty-printer.c
rename to src/libruntime/pretty-printer.c
diff --git a/src/pretty-printer.h b/src/libruntime/pretty-printer.h
similarity index 100%
rename from src/pretty-printer.h
rename to src/libruntime/pretty-printer.h
diff --git a/src/libruntime/stm32f4/jerry-assert.c b/src/libruntime/stm32f4/jerry-assert.c
new file mode 100644
index 000000000..949d80110
--- /dev/null
+++ b/src/libruntime/stm32f4/jerry-assert.c
@@ -0,0 +1,32 @@
+/* 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.
+ */
+
+#include "globals.h"
+#include "jerry-libc.h"
+
+/**
+ * Handle failed assertion
+ */
+void __noreturn
+jerry_AssertFail( const char *assertion, /**< assertion condition string */
+		  const char *file, /**< file name */
+                  const uint32_t line) /** line */
+{
+    /**
+     * TODO: Blink with LEDs.
+     *       Save call stack?
+     */
+    while( true );
+} /* jerry_AssertFail */