diff --git a/classpath/java-io.cpp b/classpath/java-io.cpp
index 1e9acdef76..db9882e051 100644
--- a/classpath/java-io.cpp
+++ b/classpath/java-io.cpp
@@ -83,6 +83,16 @@ typedef char char_t;
 
 #endif // not PLATFORM_WINDOWS
 
+#ifndef WINAPI_FAMILY
+#  ifndef WINAPI_PARTITION_DESKTOP
+#    define WINAPI_PARTITION_DESKTOP 1
+#  endif
+
+#  ifndef WINAPI_FAMILY_PARTITION
+#    define WINAPI_FAMILY_PARTITION(x) (x)
+#  endif
+#endif // WINAPI_FAMILY
+
 inline void* operator new(size_t, void* p) throw() { return p; }
 
 typedef const char_t* string_t;
@@ -214,6 +224,7 @@ extern "C" JNIEXPORT jstring JNICALL
 Java_java_io_File_toAbsolutePath(JNIEnv* e UNUSED, jclass, jstring path)
 {
 #ifdef PLATFORM_WINDOWS
+# if !defined(WINAPI_FAMILY) || WINAPI_FAMILY_PARTITION(WINAPI_PARTITION_DESKTOP)
   string_t chars = getChars(e, path);
   if (chars) {
     const unsigned BufferSize = MAX_PATH;
@@ -228,6 +239,11 @@ Java_java_io_File_toAbsolutePath(JNIEnv* e UNUSED, jclass, jstring path)
   }
 
   return path;
+# else
+  // WinRT has no concept of full paths
+  throwNewErrno(e, "java/io/IOException");
+  return path;
+# endif
 #else
   jstring result = path;
   string_t chars = getChars(e, path);
@@ -256,11 +272,24 @@ Java_java_io_File_length(JNIEnv* e, jclass, jstring path)
 
     LARGE_INTEGER fileSize;
     string_t chars = getChars(e, path);
+    #if !defined(WINAPI_FAMILY) || WINAPI_FAMILY_PARTITION(WINAPI_PARTITION_DESKTOP)
     HANDLE file = CreateFileW
       (chars, FILE_READ_DATA, FILE_SHARE_READ, 0, OPEN_EXISTING, 0, 0);
+    #else
+    HANDLE file = CreateFile2
+      (chars, GENERIC_READ, FILE_SHARE_READ, OPEN_EXISTING, nullptr);
+    #endif
     releaseChars(e, path, chars);
     if (file != INVALID_HANDLE_VALUE)
+    {
+      #if !defined(WINAPI_FAMILY) || WINAPI_FAMILY_PARTITION(WINAPI_PARTITION_DESKTOP)
       GetFileSizeEx(file, &fileSize);
+      #else
+      FILE_STANDARD_INFO info;
+      if(GetFileInformationByHandleEx(file,  FileStandardInfo, &info, sizeof(info)))
+        fileSize = info.EndOfFile;
+      #endif
+    }
     else return 0;
     CloseHandle(file);
     return static_cast<jlong>(fileSize.QuadPart);
@@ -496,7 +525,11 @@ Java_java_io_File_openDir(JNIEnv* e, jclass, jstring path)
     releaseChars(e, path, chars);
 
     Directory* d = new (malloc(sizeof(Directory))) Directory;
+    #if !defined(WINAPI_FAMILY) || WINAPI_FAMILY_PARTITION(WINAPI_PARTITION_DESKTOP)
     d->handle = FindFirstFileW(RUNTIME_ARRAY_BODY(buffer), &(d->data));
+    #else
+	d->handle = FindFirstFileExW(RUNTIME_ARRAY_BODY(buffer), FindExInfoStandard, &(d->data), FindExSearchNameMatch, NULL, 0);
+    #endif
     if (d->handle == INVALID_HANDLE_VALUE) {
       d->dispose();
       d = 0;
@@ -725,7 +758,11 @@ Java_java_io_RandomAccessFile_readBytes(JNIEnv* e, jclass, jlong peer,
   
   uint8_t* dst = reinterpret_cast<uint8_t*>
     (e->GetPrimitiveArrayCritical(buffer, 0));
+#if !defined(WINAPI_FAMILY) || WINAPI_FAMILY_PARTITION(WINAPI_PARTITION_DESKTOP)
   ssize_t bytesRead = ::read(fd, dst + offset, length);
+#else
+  auto bytesRead = ::read(fd, dst + offset, length);
+#endif
   e->ReleasePrimitiveArrayCritical(buffer, dst, 0);
   
   if(bytesRead == -1) {
@@ -737,7 +774,7 @@ Java_java_io_RandomAccessFile_readBytes(JNIEnv* e, jclass, jlong peer,
 }
 
 extern "C" JNIEXPORT void JNICALL
-Java_java_io_RandomAccessFile_close(JNIEnv*/* e*/, jclass, jlong peer)
+Java_java_io_RandomAccessFile_close(JNIEnv* /* e*/, jclass, jlong peer)
 {
   int fd = (int)peer;
   ::close(fd);
diff --git a/classpath/java-lang.cpp b/classpath/java-lang.cpp
index 4cafd5e6cc..0414216194 100644
--- a/classpath/java-lang.cpp
+++ b/classpath/java-lang.cpp
@@ -62,6 +62,16 @@
 
 #endif // not PLATFORM_WINDOWS
 
+#ifndef WINAPI_FAMILY
+#  ifndef WINAPI_PARTITION_DESKTOP
+#    define WINAPI_PARTITION_DESKTOP 1
+#  endif
+
+#  ifndef WINAPI_FAMILY_PARTITION
+#    define WINAPI_FAMILY_PARTITION(x) (x)
+#  endif
+#endif // WINAPI_FAMILY
+
 namespace {
 #ifdef PLATFORM_WINDOWS
   char* getErrorStr(DWORD err){
@@ -70,7 +80,8 @@ namespace {
     snprintf(errStr, 9, "%d", (int) err);
     return errStr;
     
-    // The better way to do this, if I could figure out how to convert LPTSTR to char*
+	//TODO:
+	// The better way to do this, if I could figure out how to convert LPTSTR to char*
     //char* errStr;
     //LPTSTR s;
     //if(FormatMessage(FORMAT_MESSAGE_ALLOCATE_BUFFER | FORMAT_MESSAGE_FROM_SYSTEM |
@@ -83,6 +94,7 @@ namespace {
     //return errStr;
   }
 
+#if !defined(WINAPI_FAMILY) || WINAPI_FAMILY_PARTITION(WINAPI_PARTITION_DESKTOP)
   void makePipe(JNIEnv* e, HANDLE p[2])
   {
     SECURITY_ATTRIBUTES sa;
@@ -95,6 +107,7 @@ namespace {
       throwNew(e, "java/io/IOException", getErrorStr(GetLastError()));
     }
   }
+#endif
   
   int descriptor(JNIEnv* e, HANDLE h)
   {
@@ -196,7 +209,7 @@ extern "C" JNIEXPORT void JNICALL
 Java_java_lang_Runtime_exec(JNIEnv* e, jclass, 
                             jobjectArray command, jlongArray process)
 {
-  
+#if !defined(WINAPI_FAMILY) || WINAPI_FAMILY_PARTITION(WINAPI_PARTITION_DESKTOP)
   int size = 0;
   for (int i = 0; i < e->GetArrayLength(command); ++i){
     jstring element = (jstring) e->GetObjectArrayElement(command, i);
@@ -267,11 +280,15 @@ Java_java_lang_Runtime_exec(JNIEnv* e, jclass,
   e->SetLongArrayRegion(process, 0, 1, &pid);
   jlong tid = reinterpret_cast<jlong>(pi.hThread);  
   e->SetLongArrayRegion(process, 1, 1, &tid);
+#else
+  throwNew(e, "java/io/Exception", strdup("Not supported on WinRT/WinPhone8"));
+#endif
 }
 
 extern "C" JNIEXPORT jint JNICALL 
 Java_java_lang_Runtime_waitFor(JNIEnv* e, jclass, jlong pid, jlong tid)
 {
+#if !defined(WINAPI_FAMILY) || WINAPI_FAMILY_PARTITION(WINAPI_PARTITION_DESKTOP)
   DWORD exitCode;
   WaitForSingleObject(reinterpret_cast<HANDLE>(pid), INFINITE);
   BOOL success = GetExitCodeProcess(reinterpret_cast<HANDLE>(pid), &exitCode);
@@ -283,14 +300,23 @@ Java_java_lang_Runtime_waitFor(JNIEnv* e, jclass, jlong pid, jlong tid)
   CloseHandle(reinterpret_cast<HANDLE>(tid));
 
   return exitCode;
+#else
+  throwNew(e, "java/io/Exception", strdup("Not supported on WinRT/WinPhone8"));
+  return -1;
+#endif
 }
 
 extern "C" JNIEXPORT void JNICALL
-Java_java_lang_Runtime_kill(JNIEnv*, jclass, jlong pid) {
+Java_java_lang_Runtime_kill(JNIEnv* e UNUSED, jclass, jlong pid) {
+#if !defined(WINAPI_FAMILY) || WINAPI_FAMILY_PARTITION(WINAPI_PARTITION_DESKTOP)
   TerminateProcess(reinterpret_cast<HANDLE>(pid), 1);
+#else
+  throwNew(e, "java/io/Exception", strdup("Not supported on WinRT/WinPhone8"));
+#endif
 }
 
 Locale getLocale() {
+#if !defined(WINAPI_FAMILY) || WINAPI_FAMILY_PARTITION(WINAPI_PARTITION_DESKTOP)
   const char* lang = "";
   const char* reg = "";
   unsigned langid = GetUserDefaultUILanguage();
@@ -362,8 +388,11 @@ Locale getLocale() {
     default: lang = "en";
   }
 
-  Locale locale(lang, reg);
-  return locale;
+  return Locale(lang, reg);
+#else
+  //TODO: CultureInfo.CurrentCulture
+  return Locale("en", "US");
+#endif
 }
 #else
 extern "C" JNIEXPORT void JNICALL 
@@ -531,8 +560,15 @@ Java_java_lang_System_getProperty(JNIEnv* e, jclass, jstring name,
     } else if (strcmp(chars, "file.separator") == 0) {
       r = e->NewStringUTF("\\");
     } else if (strcmp(chars, "os.name") == 0) {
+#  if !defined(WINAPI_FAMILY) || WINAPI_FAMILY_PARTITION(WINAPI_PARTITION_DESKTOP)
       r = e->NewStringUTF("Windows");
+#  elif WINAPI_FAMILY_PARTITION(WINAPI_PARTITION_PHONE)
+      r = e->NewStringUTF("Windows Phone");
+#  else
+      r = e->NewStringUTF("Windows RT");
+#  endif
     } else if (strcmp(chars, "os.version") == 0) {
+#  if !defined(WINAPI_FAMILY) || WINAPI_FAMILY_PARTITION(WINAPI_PARTITION_DESKTOP)
       unsigned size = 32;
       RUNTIME_ARRAY(char, buffer, size);
       OSVERSIONINFO OSversion;
@@ -540,6 +576,10 @@ Java_java_lang_System_getProperty(JNIEnv* e, jclass, jstring name,
       ::GetVersionEx(&OSversion);
       snprintf(RUNTIME_ARRAY_BODY(buffer), size, "%i.%i", (int)OSversion.dwMajorVersion, (int)OSversion.dwMinorVersion);
       r = e->NewStringUTF(RUNTIME_ARRAY_BODY(buffer));
+#  else
+      // Currently there is no alternative on WinRT/WP8
+      r = e->NewStringUTF("8.0");
+#  endif
     } else if (strcmp(chars, "os.arch") == 0) {
 #ifdef ARCH_x86_32
       r = e->NewStringUTF("x86");
@@ -551,15 +591,28 @@ Java_java_lang_System_getProperty(JNIEnv* e, jclass, jstring name,
       r = e->NewStringUTF("arm");
 #endif
     } else if (strcmp(chars, "java.io.tmpdir") == 0) {
+#  if !defined(WINAPI_FAMILY) || WINAPI_FAMILY_PARTITION(WINAPI_PARTITION_DESKTOP)
       TCHAR buffer[MAX_PATH];
       GetTempPath(MAX_PATH, buffer);
       r = e->NewStringUTF(buffer);
+#  else
+      //TODO:http://lunarfrog.com/blog/2012/05/21/winrt-folders-access/
+	  //Windows.Storage.ApplicationData.Current.TemporaryFolder
+      r = 0;
+#  endif
     } else if (strcmp(chars, "user.dir") == 0) {
+#  if !defined(WINAPI_FAMILY) || WINAPI_FAMILY_PARTITION(WINAPI_PARTITION_DESKTOP)
       TCHAR buffer[MAX_PATH];
       GetCurrentDirectory(MAX_PATH, buffer);
       r = e->NewStringUTF(buffer);
+#  else
+      //TODO:http://lunarfrog.com/blog/2012/05/21/winrt-folders-access/
+	  //Windows.ApplicationModel.Package.Current.InstalledLocation
+      r = 0;
+#  endif
     } else if (strcmp(chars, "user.home") == 0) {
 #  ifdef _MSC_VER
+#    if !defined(WINAPI_FAMILY) || WINAPI_FAMILY_PARTITION(WINAPI_PARTITION_DESKTOP)
       WCHAR buffer[MAX_PATH];
       size_t needed;
       if (_wgetenv_s(&needed, buffer, MAX_PATH, L"USERPROFILE") == 0) {
@@ -567,6 +620,11 @@ Java_java_lang_System_getProperty(JNIEnv* e, jclass, jstring name,
       } else {
         r = 0;
       }
+#    else
+      //TODO:http://lunarfrog.com/blog/2012/05/21/winrt-folders-access/
+	  //Windows.Storage.KnownFolders.DocumentsLibrary;
+      r = 0;
+#    endif
 #  else
       LPWSTR home = _wgetenv(L"USERPROFILE");
       r = e->NewString(reinterpret_cast<jchar*>(home), lstrlenW(home));
@@ -654,6 +712,9 @@ namespace {
 #elif defined __APPLE__
 #  include <crt_externs.h>
 #  define environ (*_NSGetEnviron())
+#elif defined(WINAPI_FAMILY) && !WINAPI_FAMILY_PARTITION(WINAPI_PARTITION_DESKTOP)
+// WinRT/WP8 does not provide alternative for environment variables
+char* environ[] = { 0 };
 #else
 extern char** environ;
 #endif
diff --git a/makefile b/makefile
index 9b4ffb954a..28ef8be401 100755
--- a/makefile
+++ b/makefile
@@ -51,7 +51,7 @@ ifeq ($(continuations),true)
 endif
 
 root := $(shell (cd .. && pwd))
-build = build/$(platform)-$(arch)$(options)
+build = $(build-prefix)build/$(platform)-$(arch)$(options)
 classpath-build = $(build)/classpath
 test-build = $(build)/test
 src = src
@@ -59,6 +59,8 @@ classpath-src = classpath
 test = test
 win32 ?= $(root)/win32
 win64 ?= $(root)/win64
+winrt ?= $(root)/winrt
+wp8 ?= $(root)/wp8
 
 classpath = avian
 
@@ -183,6 +185,18 @@ strip-all = --strip-all
 
 rdynamic = -rdynamic
 
+cflags_debug = -O0 -g3
+cflags_debug_fast = -O0 -g3
+cflags_stress = -O0 -g3
+cflags_stress_major = -O0 -g3
+ifeq ($(use-clang),true)
+	cflags_fast = -O4 -g3
+	cflags_small = -Oz -g3
+else
+	cflags_fast = -O3 -g3
+	cflags_small = -Os -g3
+endif
+
 # note that we suppress the non-virtual-dtor warning because we never
 # use the delete operator, which means we don't need virtual
 # destructors:
@@ -198,7 +212,7 @@ common-cflags = $(warnings) -fno-rtti -fno-exceptions -I$(classpath-src) \
 	-DUSE_ATOMIC_OPERATIONS -DAVIAN_JAVA_HOME=\"$(javahome)\" \
 	-DAVIAN_EMBED_PREFIX=\"$(embed-prefix)\" $(target-cflags)
 
-asmflags = $(target-cflags)
+asmflags = $(target-cflags) -I$(src)
 
 ifneq (,$(filter i386 x86_64,$(arch)))
 	ifeq ($(use-frame-pointer),true)
@@ -237,6 +251,18 @@ pointer-size = 8
 so-prefix = lib
 so-suffix = .so
 
+static-prefix = lib
+static-suffix = .a
+
+output = -o $(1)
+asm-output = -o $(1)
+asm-input = -c $(1)
+asm-format = S
+as = $(cc)
+ld = $(cxx)
+build-ld = $(build-cc)
+
+static = -static
 shared = -shared
 
 no-error = -Wno-error
@@ -244,6 +270,8 @@ no-error = -Wno-error
 openjdk-extra-cflags = -fvisibility=hidden
 
 bootimage-cflags = -DTARGET_BYTES_PER_WORD=$(pointer-size)
+bootimage-symbols = _binary_bootimage_bin_start:_binary_bootimage_bin_end
+codeimage-symbols = _binary_codeimage_bin_start:_binary_codeimage_bin_end
 
 developer-dir := $(shell if test -d /Developer; then echo /Developer; \
 	else echo /Applications/Xcode.app/Contents/Developer; fi)
@@ -354,41 +382,68 @@ ifeq ($(platform),freebsd)
 	cflags = $(build-cflags)
 endif
 ifeq ($(platform),android)
-    asm = arm
-	pointer-size = 4
-	no-psabi = -Wno-psabi
-	use-lto = false
-	ifeq ($(build-platform),cygwin)
+    ifeq ($(build-platform),cygwin)
 		ndk = "$$(cygpath -u "$(ANDROID_NDK)")"
 	else
 		ndk = $(ANDROID_NDK)
 	endif
 
+	ifeq ($(android-version),)
+		android-version = 5
+	endif
+
+	ifeq ($(android-toolchain),)
+		android-toolchain = 4.7
+	endif
+
+	ifeq ($(arch),arm)
+		android-toolchain-name = arm-linux-androideabi
+		android-toolchain-prefix = arm-linux-androideabi-
+	endif
+	ifeq ($(arch),i386)
+		android-toolchain-name = x86
+		android-toolchain-prefix = i686-linux-android-
+	endif
+
+	ifeq ($(android-arm-arch),)
+		android-arm-arch = armv5
+	endif
+
+	options := $(options)-api$(android-version)-$(android-toolchain)-$(android-arm-arch)
+
 	build-cflags = $(common-cflags) -I$(src)
-	#build-lflags = -lz -lpthread -ldl
+	build-lflags = -lz -lpthread
 	ifeq ($(subst cygwin,windows,$(subst mingw32,windows,$(build-platform))),windows)
 		toolchain-host-platform = $(subst cygwin,windows,$(subst mingw32,windows,$(build-platform)))
 		build-system = windows
 		build-cxx = i686-w64-mingw32-g++
 		build-cc = i686-w64-mingw32-gcc
-		sysroot = "$$(cygpath -w "$(ndk)/platforms/android-5/arch-arm")"
+		sysroot = "$$(cygpath -w "$(ndk)/platforms/android-$(android-version)/arch-arm")"
 		build-cflags += "-I$(JAVA_HOME)/include/win32"
 	else
 		toolchain-host-platform = $(subst cygwin,windows,$(subst mingw32,windows,$(build-platform)))-*
-		sysroot = $(ndk)/platforms/android-5/arch-arm
+		sysroot = $(ndk)/platforms/android-$(android-version)/arch-arm
 		build-cflags += "-I$(JAVA_HOME)/include/linux"
+		build-lflags += -ldl
 	endif
-	toolchain = $(ndk)/toolchains/arm-linux-androideabi-4.7/prebuilt/$(toolchain-host-platform)
-	cflags = "-I$(sysroot)/usr/include" "-I$(JAVA_HOME)/include/linux" $(common-cflags) "-I$(src)" -std=c++11 -marm $(no-psabi)
-	lflags = "-L$(sysroot)/usr/lib" $(common-lflags) -ldl
+	toolchain = $(ndk)/toolchains/$(android-toolchain-name)-$(android-toolchain)/prebuilt/$(toolchain-host-platform)
+	cflags = "-I$(sysroot)/usr/include" "-I$(JAVA_HOME)/include/linux" $(common-cflags) "-I$(src)" -std=c++11 $(no-psabi)
+	lflags = "-L$(sysroot)/usr/lib" $(common-lflags) -llog
+	target-format = elf
 	use-lto = false
 	
-	cxx = $(toolchain)/bin/arm-linux-androideabi-g++ --sysroot="$(sysroot)"
-	cc = $(toolchain)/bin/arm-linux-androideabi-gcc --sysroot="$(sysroot)"
-	as = $(toolchain)/bin/arm-linux-androideabi-as --sysroot="$(sysroot)"
-	ar = $(toolchain)/bin/arm-linux-androideabi-ar
-	ranlib = $(toolchain)/bin/arm-linux-androideabi-ranlib
-	strip = $(toolchain)/bin/arm-linux-androideabi-strip
+	ifeq ($(arch),arm)
+		cflags += -marm -march=$(android-arm-arch) -ftree-vectorize -ffast-math -mfloat-abi=softfp
+	endif
+	ifeq ($(arch),i386)
+	endif
+
+	cxx = $(toolchain)/bin/$(android-toolchain-prefix)g++ --sysroot="$(sysroot)"
+	cc = $(toolchain)/bin/$(android-toolchain-prefix)gcc --sysroot="$(sysroot)"
+	as = $(cxx)
+	ar = $(toolchain)/bin/$(android-toolchain-prefix)ar
+	ranlib = $(toolchain)/bin/$(android-toolchain-prefix)ranlib
+	strip = $(toolchain)/bin/$(android-toolchain-prefix)strip
 endif
 
 ifeq ($(platform),darwin)
@@ -475,7 +530,9 @@ ifeq ($(platform),darwin)
 endif
 
 ifeq ($(platform),windows)
-	target-format = pe
+	ifeq ($(target-format),)
+		target-format = pe
+	endif
 
 	inc = "$(win32)/include"
 	lib = "$(win32)/lib"
@@ -488,7 +545,8 @@ ifeq ($(platform),windows)
 	so-suffix = .dll
 	exe-suffix = .exe
 
-	lflags = -L$(lib) $(common-lflags) -lws2_32 -liphlpapi -mwindows -mconsole
+	lflags = -L$(lib) $(common-lflags) -lws2_32 -liphlpapi -mconsole
+	bootimage-generator-lflags = -static-libstdc++ -static-libgcc
 	cflags = -I$(inc) $(common-cflags) -DWINVER=0x0500
 
 	ifeq (,$(filter mingw32 cygwin,$(build-platform)))
@@ -539,39 +597,197 @@ ifeq ($(platform),windows)
 	embed-loader-o = $(build-embed)/embed-loader.o
 endif
 
+ifeq ($(platform),wp8)
+	ifeq ($(shell uname -s | grep -i -c WOW64),1)
+		programFiles = Program Files (x86)
+	else
+		programFiles = Program Files
+	endif
+	ifeq ($(MSVS_ROOT),)
+		# Environment variable MSVS_ROOT not found. It should be something like
+		# "C:\$(programFiles)\Microsoft Visual Studio 11.0"
+		MSVS_ROOT = C:\$(programFiles)\Microsoft Visual Studio 11.0
+	endif
+	ifeq ($(MSVC_ROOT),)
+		# Environment variable MSVC_ROOT not found. It should be something like
+		# "C:\$(programFiles)\Microsoft Visual Studio 11.0\VC"
+		MSVC_ROOT = $(MSVS_ROOT)\VC
+	endif
+	ifeq ($(WP80_SDK),)
+		# Environment variable WP8_SDK not found. It should be something like
+		# "C:\Program Files[ (x86)]\Microsoft Visual Studio 11.0\VC\WPSDK\WP80"
+		# TODO: Lookup in SOFTWARE\Microsoft\Microsoft SDKs\WindowsPhone\v8.0
+		WP80_SDK = C:\$(programFiles)\Microsoft Visual Studio 11.0\VC\WPSDK\WP80
+	endif
+	ifeq ($(WP80_KIT),)
+		# Environment variable WP8_KIT not found. It should be something like
+		# "c:\Program Files[ (x86)]\Windows Phone Kits\8.0"
+		# TODO: Lookup in SOFTWARE\Microsoft\Microsoft SDKs\WindowsPhone\v8.0
+		WP80_KIT = C:\$(programFiles)\Windows Phone Kits\8.0
+	endif
+	ifeq ($(WIN8_KIT),)
+		# Environment variable WIN8_KIT not found. It should be something like
+		# "c:\Program Files[ (x86)]\Windows Kits\8.0"
+		WIN8_KIT = C:\$(programFiles)\Windows Kits\8.0
+	endif
+	ifeq ($(build-platform),cygwin)
+		windows-path = cygpath -w
+	else
+		windows-path = $(native-path)
+	endif
+	windows-java-home := $(shell $(windows-path) "$(JAVA_HOME)")
+	target-format = pe
+	ms_cl_compiler = wp8
+	use-lto = false
+	supports_avian_executable = false
+	process = interpret
+	ifneq ($(process),compile)
+		options := -$(process)
+	endif
+	bootimage = true
+	ifeq ($(bootimage),true)
+		options := $(options)-bootimage
+	endif
+	system = windows
+	build-system = windows
+	static-prefix =
+	static-suffix = .lib
+	so-prefix =
+	so-suffix = .dll
+	exe-suffix = .exe
+
+	ifeq ($(arch),arm)
+		wp8_arch = \x86_arm
+		vc_arch = \arm
+		w8kit_arch = arm
+		deps_arch = ARM
+		as = "$$(cygpath -u "$(WP80_SDK)\bin\x86_arm\armasm.exe")"
+		cxx = "$$(cygpath -u "$(WP80_SDK)\bin\x86_arm\cl.exe")"
+		ld = "$$(cygpath -u "$(WP80_SDK)\bin\x86_arm\link.exe")"
+		asmflags = -machine ARM -32
+		asm-output = -o $(1)
+		asm-input = $(1)
+		machine_type = ARM
+		bootimage-symbols = binary_bootimage_bin_start:binary_bootimage_bin_end
+		codeimage-symbols = binary_codeimage_bin_start:binary_codeimage_bin_end
+	endif
+	ifeq ($(arch),i386)
+		wp8_arch =
+		vc_arch =
+		w8kit_arch = x86
+		deps_arch = x86
+		as = "$$(cygpath -u "$(WP80_SDK)\bin\ml.exe")"
+		cxx = "$$(cygpath -u "$(WP80_SDK)\bin\cl.exe")"
+		ld = "$$(cygpath -u "$(WP80_SDK)\bin\link.exe")"
+		asmflags += -nologo
+		asm-output = $(output)
+		machine_type = X86
+	endif
+
+	PATH := $(shell cygpath -u "$(MSVS_ROOT)\Common7\IDE"):$(shell cygpath -u "$(WP80_SDK)\bin$(wp8_arch)"):$(shell cygpath -u "$(WP80_SDK)\bin"):${PATH}
+
+	build-cflags = $(common-cflags) -I$(src) -I$(inc) -mthreads
+	build-lflags = -lz -lpthread
+
+	cflags = -nologo \
+		-I"$(WP80_SDK)\include" -I"$(WP80_KIT)\Include" -I"$(WP80_KIT)\Include\minwin" -I"$(WP80_KIT)\Include\mincore" \
+		-DWINAPI_FAMILY=WINAPI_FAMILY_PHONE_APP \
+		-DAVIAN_VERSION=\"$(version)\" -D_JNI_IMPLEMENTATION_ \
+		-DUSE_ATOMIC_OPERATIONS -DAVIAN_JAVA_HOME=\"$(javahome)\" \
+		-DAVIAN_EMBED_PREFIX=\"$(embed-prefix)\" \
+		-I"$(shell $(windows-path) "$(wp8)/zlib/upstream")" \
+		-Fd$(build)/$(name).pdb -I"$(shell $(windows-path) "$(wp8)/include")" -I$(src) -I$(classpath-src) \
+		-I"$(build)" \
+		-I"$(windows-java-home)/include" -I"$(windows-java-home)/include/win32" \
+		-DTARGET_BYTES_PER_WORD=$(pointer-size)
+
+	common-lflags = $(classpath-lflags)
+
+	arflags = -MACHINE:$(machine_type)
+	lflags = $(common-lflags) -nologo \
+		-MACHINE:$(machine_type) \
+		-LIBPATH:"$(WP80_KIT)\lib\$(w8kit_arch)" -LIBPATH:"$(WIN8_KIT)\Lib\win8\um\$(w8kit_arch)" -LIBPATH:"$(MSVC_ROOT)\lib$(vc_arch)" \
+		ws2_32.lib \
+		"$(shell $(windows-path) "$(wp8)\lib\$(deps_arch)\zlib.lib")" "$(shell $(windows-path) "$(wp8)\lib\$(deps_arch)\ThreadEmulation.lib")"
+
+	cc = $(cxx)
+	asm-format = masm
+	shared = -dll
+	ar = "$$(cygpath -u "$(WP80_SDK)\bin\lib.exe")"
+	arflags += -nologo
+	ifeq ($(build-platform),cygwin)
+		build-cxx = i686-w64-mingw32-g++
+		build-cc = i686-w64-mingw32-gcc
+		dlltool = i686-w64-mingw32-dlltool
+		ranlib =
+		strip =
+	endif
+	output = -Fo$(1)
+
+	cflags_debug = -Od -Zi -MDd
+	cflags_debug_fast = -Od -Zi -MDd
+	cflags_stress = -O0 -g3 -MD
+	cflags_stress_major = -O0 -g3 -MD
+	cflags_fast = -O2 -Zi -MD
+	cflags_small = -O1s -Zi -MD
+	# -GL [whole program optimization] in 'fast' and 'small' breaks compilation for some reason
+
+	ifeq ($(mode),debug)
+		cflags +=
+		lflags +=
+	endif
+	ifeq ($(mode),debug-fast)
+		cflags += -DNDEBUG
+		lflags +=
+	endif
+	ifeq ($(mode),stress_major)
+		cflags +=
+		lflags +=
+	endif
+	ifeq ($(mode),fast)
+		cflags +=
+		lflags +=
+	endif
+	# -LTCG is needed only if -GL is used
+	ifeq ($(mode),fast)
+		cflags += -DNDEBUG
+		lflags += -LTCG
+		arflags +=
+	endif
+	ifeq ($(mode),small)
+		cflags += -DNDEBUG
+		lflags += -LTCG
+		arflags +=
+	endif
+
+	strip = :
+endif
+
 ifeq ($(mode),debug)
-	optimization-cflags = -O0 -g3
-	converter-cflags += -O0 -g3
+	optimization-cflags = $(cflags_debug)
+	converter-cflags += $(cflags_debug)
 	strip = :
 endif
 ifeq ($(mode),debug-fast)
-	optimization-cflags = -O0 -g3 -DNDEBUG
+	optimization-cflags = $(cflags_debug_fast) -DNDEBUG
 	strip = :
 endif
 ifeq ($(mode),stress)
-	optimization-cflags = -O0 -g3 -DVM_STRESS
+	optimization-cflags = $(cflags_stress) -DVM_STRESS
 	strip = :
 endif
 ifeq ($(mode),stress-major)
-	optimization-cflags = -O0 -g3 -DVM_STRESS -DVM_STRESS_MAJOR
+	optimization-cflags = $(cflags_stress_major) -DVM_STRESS -DVM_STRESS_MAJOR
 	strip = :
 endif
 ifeq ($(mode),fast)
-	ifeq ($(use-clang),true)
-		optimization-cflags = -O4 -g3 -DNDEBUG
-	else
-		optimization-cflags = -O3 -g3 -DNDEBUG
-	endif
+	optimization-cflags = $(cflags_fast) -DNDEBUG
 	ifeq ($(use-lto),)
 		use-lto = true
 	endif
 endif
 ifeq ($(mode),small)
-	ifeq ($(use-clang),true)
-		optimization-cflags = -Oz -g3 -DNDEBUG
-	else
-		optimization-cflags = -Os -g3 -DNDEBUG
-	endif
+	optimization-cflags = $(cflags_small) -DNDEBUG
 	ifeq ($(use-lto),)
 		use-lto = true
 	endif
@@ -596,6 +812,7 @@ endif
 
 cflags += $(optimization-cflags)
 
+ifndef ms_cl_compiler
 ifneq ($(platform),darwin)
 ifeq ($(arch),i386)
 # this is necessary to support __sync_bool_compare_and_swap:
@@ -603,16 +820,9 @@ ifeq ($(arch),i386)
 	lflags += -march=i586
 endif
 endif
-
-output = -o $(1)
-as := $(cc)
-ld := $(cc)
-build-ld := $(build-cc)
-
-static = -static
+endif
 
 ifdef msvc
-  static =
 	no-error =
 	windows-path = $(native-path)
 	windows-java-home := $(shell $(windows-path) "$(JAVA_HOME)")
@@ -621,6 +831,7 @@ ifdef msvc
 	cc = $(cxx)
 	ld = "$(msvc)/BIN/link.exe"
 	mt = "mt.exe"
+	manifest-flags = -MANIFEST -MANIFESTFILE:$(@).manifest
 	cflags = -nologo -DAVIAN_VERSION=\"$(version)\" -D_JNI_IMPLEMENTATION_ \
 		-DUSE_ATOMIC_OPERATIONS -DAVIAN_JAVA_HOME=\"$(javahome)\" \
 		-DAVIAN_EMBED_PREFIX=\"$(embed-prefix)\" \
@@ -629,7 +840,7 @@ ifdef msvc
 		-I"$(windows-java-home)/include" -I"$(windows-java-home)/include/win32" \
 		-DTARGET_BYTES_PER_WORD=$(pointer-size)
 
-  ifneq ($(lzma),)
+	ifneq ($(lzma),)
 		cflags += -I$(shell $(windows-path) "$(lzma)")
 	endif
 
@@ -656,9 +867,11 @@ ifdef msvc
 	strip = :
 endif
 
+build-cflags += -DAVIAN_HOST_TARGET
+
 c-objects = $(foreach x,$(1),$(patsubst $(2)/%.c,$(3)/%.o,$(x)))
 cpp-objects = $(foreach x,$(1),$(patsubst $(2)/%.cpp,$(3)/%.o,$(x)))
-asm-objects = $(foreach x,$(1),$(patsubst $(2)/%.S,$(3)/%-asm.o,$(x)))
+asm-objects = $(foreach x,$(1),$(patsubst $(2)/%.$(asm-format),$(3)/%-asm.o,$(x)))
 java-classes = $(foreach x,$(1),$(patsubst $(2)/%.java,$(3)/%.class,$(x)))
 
 generated-code = \
@@ -684,7 +897,7 @@ vm-sources = \
 	$(src)/jnienv.cpp \
 	$(src)/process.cpp
 
-vm-asm-sources = $(src)/$(asm).S
+vm-asm-sources = $(src)/$(asm).$(asm-format)
 
 target-asm = $(asm)
 
@@ -702,8 +915,9 @@ ifeq ($(process),compile)
 		$(src)/compiler.cpp \
 		$(src)/$(target-asm).cpp
 
-	vm-asm-sources += $(src)/compile-$(asm).S
+	vm-asm-sources += $(src)/compile-$(asm).$(asm-format)
 endif
+cflags += -DAVIAN_PROCESS_$(process)
 
 vm-cpp-objects = $(call cpp-objects,$(vm-sources),$(src),$(build))
 vm-asm-objects = $(call asm-objects,$(vm-asm-sources),$(src),$(build))
@@ -835,7 +1049,7 @@ converter-objects = $(call cpp-objects,$(converter-sources),$(src),$(build))
 converter-tool-objects = $(call cpp-objects,$(converter-tool-sources),$(src),$(build))
 converter = $(build)/binaryToObject/binaryToObject
 
-static-library = $(build)/lib$(name).a
+static-library = $(build)/$(static-prefix)$(name)${static-suffix}
 executable = $(build)/$(name)${exe-suffix}
 dynamic-library = $(build)/$(so-prefix)jvm$(so-suffix)
 executable-dynamic = $(build)/$(name)-dynamic${exe-suffix}
@@ -945,9 +1159,15 @@ test-flags = -Djava.library.path=$(build) -cp $(build)/test
 test-args = $(test-flags) $(input)
 
 .PHONY: build
+ifneq ($(supports_avian_executable),false)
 build: $(static-library) $(executable) $(dynamic-library) $(lzma-loader) \
 	$(lzma-encoder) $(executable-dynamic) $(classpath-dep) $(test-dep) \
 	$(test-extra-dep) $(embed)
+else
+build: $(static-library) $(dynamic-library) $(lzma-loader) \
+	$(lzma-encoder) $(classpath-dep) $(test-dep) \
+	$(test-extra-dep) $(embed)
+endif
 
 $(test-dep): $(classpath-dep)
 
@@ -992,7 +1212,7 @@ clean:
 	@echo "removing build"
 	rm -rf build
 
-$(build)/compile-x86-asm.o: $(src)/continuations-x86.S
+$(build)/compile-x86-asm.o: $(src)/continuations-x86.$(asm-format)
 
 gen-arg = $(shell echo $(1) | sed -e 's:$(build)/type-\(.*\)\.cpp:\1:')
 $(generated-code): %.cpp: $(src)/types.def $(generator) $(classpath-dep)
@@ -1043,7 +1263,7 @@ endef
 define compile-asm-object
 	@echo "compiling $(@)"
 	@mkdir -p $(dir $(@))
-	$(as) -I$(src) $(asmflags) -c $(<) -o $(@)
+	$(as) $(asmflags) $(call asm-output,$(@)) $(call asm-input,$(<))
 endef
 
 $(vm-cpp-objects): $(build)/%.o: $(src)/%.cpp $(vm-depends)
@@ -1054,10 +1274,12 @@ $(test-cpp-objects): $(test-build)/%.o: $(test)/%.cpp $(vm-depends)
 
 $(test-library): $(test-cpp-objects)
 	@echo "linking $(@)"
-ifdef msvc
+ifdef ms_cl_compiler
 	$(ld) $(shared) $(lflags) $(^) -out:$(@) -PDB:$(@).pdb \
-		-IMPLIB:$(test-build)/$(name).lib -MANIFESTFILE:$(@).manifest
-	$(mt) -manifest $(@).manifest -outputresource:"$(@);2"
+		-IMPLIB:$(test-build)/$(name).lib $(manifest-flags)
+ifdef mt
+	$(mt) -nologo -manifest $(@).manifest -outputresource:"$(@);2"
+endif
 else
 	$(ld) $(^) $(shared) $(lflags) -o $(@)
 endif
@@ -1065,10 +1287,12 @@ endif
 ifdef embed
 $(embed): $(embed-objects) $(embed-loader-o)
 	@echo "building $(embed)"
-ifdef msvc
+ifdef ms_cl_compiler
 	$(ld) $(lflags) $(^) -out:$(@) -PDB:$(@).pdb \
-		-IMPLIB:$(@).lib -MANIFESTFILE:$(@).manifest
-	$(mt) -manifest $(@).manifest -outputresource:"$(@);1"
+		-IMPLIB:$(@).lib $(manifest-flags)
+ifdef mt
+	$(mt) -nologo -manifest $(@).manifest -outputresource:"$(@);1"
+endif
 else
 	$(cxx) $(^) $(lflags) $(static) $(call output,$(@))
 endif
@@ -1086,10 +1310,12 @@ $(embed-loader-o): $(embed-loader) $(converter)
 $(embed-loader): $(embed-loader-objects) $(static-library)
 	@mkdir -p $(dir $(@))
 	cd $(dir $(@)) && $(ar) x ../../../$(static-library)
-ifdef msvc
+ifdef ms_cl_compiler
 	$(ld) $(lflags) $(dir $(@))/*.o -out:$(@) -PDB:$(@).pdb \
-		-IMPLIB:$(@).lib -MANIFESTFILE:$(@).manifest
-	$(mt) -manifest $(@).manifest -outputresource:"$(@);1"
+		-IMPLIB:$(@).lib $(manifest-flags)
+ifdef mt
+	$(mt) -nologo -manifest $(@).manifest -outputresource:"$(@);1"
+endif
 else
 	$(dlltool) -z $(addsuffix .def,$(basename $(@))) $(dir $(@))/*.o
 	$(dlltool) -d $(addsuffix .def,$(basename $(@))) -e $(addsuffix .exp,$(basename $(@))) 
@@ -1109,7 +1335,7 @@ $(build)/%.o: $(lzma)/C/%.c
 	@mkdir -p $(dir $(@))
 	$(cxx) $(cflags) $(no-error) -c $$($(windows-path) $(<)) $(call output,$(@))
 
-$(vm-asm-objects): $(build)/%-asm.o: $(src)/%.S
+$(vm-asm-objects): $(build)/%-asm.o: $(src)/%.$(asm-format)
 	$(compile-asm-object)
 
 $(bootimage-generator-objects): $(build)/%.o: $(src)/%.cpp $(vm-depends)
@@ -1196,14 +1422,18 @@ $(static-library): $(vm-objects) $(classpath-objects) $(vm-heapwalk-objects) \
 		$(javahome-object) $(boot-javahome-object) $(lzma-decode-objects)
 	@echo "creating $(@)"
 	rm -rf $(@)
+ifdef ms_cl_compiler
+	$(ar) $(arflags) $(^) -out:$(@)
+else
 	$(ar) cru $(@) $(^)
 	$(ranlib) $(@)
+endif
 
-$(bootimage-object) $(codeimage-object): $(bootimage-generator) \
-		$(build)/classpath.jar
+$(bootimage-object) $(codeimage-object): $(bootimage-generator)
+	@echo "generating bootimage and codeimage binaries using $(<)"
 	$(<) -cp $(classpath-build) -bootimage $(bootimage-object) -codeimage $(codeimage-object) \
-		-bootimage-symbols _binary_bootimage_bin_start:_binary_bootimage_bin_end \
-		-codeimage-symbols _binary_codeimage_bin_start:_binary_codeimage_bin_end
+		-bootimage-symbols $(bootimage-symbols) \
+		-codeimage-symbols $(codeimage-symbols)
 
 executable-objects = $(vm-objects) $(classpath-objects) $(driver-object) \
 	$(vm-heapwalk-objects) $(boot-object) $(vm-classpath-objects) \
@@ -1212,10 +1442,12 @@ executable-objects = $(vm-objects) $(classpath-objects) $(driver-object) \
 $(executable): $(executable-objects)
 	@echo "linking $(@)"
 ifeq ($(platform),windows)
-ifdef msvc
+ifdef ms_cl_compiler
 	$(ld) $(lflags) $(executable-objects) -out:$(@) -PDB:$(@).pdb \
-		-IMPLIB:$(@).lib -MANIFESTFILE:$(@).manifest
-	$(mt) -manifest $(@).manifest -outputresource:"$(@);1"
+		-IMPLIB:$(@).lib $(manifest-flags)
+ifdef mt
+	$(mt) -nologo -manifest $(@).manifest -outputresource:"$(@);1"
+endif
 else
 	$(dlltool) -z $(@).def $(executable-objects)
 	$(dlltool) -d $(@).def -e $(@).exp
@@ -1229,6 +1461,7 @@ endif
 $(bootimage-generator): $(bootimage-generator-objects)
 	echo arch=$(arch) platform=$(platform)
 	$(MAKE) mode=$(mode) \
+		build-prefix=$(build)/host/ \
 		arch=$(build-arch) \
 		target-arch=$(arch) \
 		platform=$(bootimage-platform) \
@@ -1247,17 +1480,19 @@ $(build-bootimage-generator): \
 		$(lzma-decode-objects) $(lzma-encode-objects)
 	@echo "linking $(@)"
 ifeq ($(platform),windows)
-ifdef msvc
-	$(ld) $(lflags) $(^) -out:$(@) -PDB:$(@).pdb -IMPLIB:$(@).lib \
-		-MANIFESTFILE:$(@).manifest
-	$(mt) -manifest $(@).manifest -outputresource:"$(@);1"
+ifdef ms_cl_compiler
+	$(ld) $(lflags) $(^) -out:$(@) -PDB:$(@).pdb \
+		-IMPLIB:$(@).lib $(manifest-flags)
+ifdef mt
+	$(mt) -nologo -manifest $(@).manifest -outputresource:"$(@);1"
+endif
 else
 	$(dlltool) -z $(@).def $(^)
 	$(dlltool) -d $(@).def -e $(@).exp
-	$(ld) $(@).exp $(^) $(lflags) -o $(@)
+	$(ld) $(@).exp $(^) $(bootimage-generator-lflags) $(lflags) -o $(@)
 endif
 else
-	$(ld) $(^) $(rdynamic) $(lflags) -o $(@)
+	$(ld) $(^) $(rdynamic) $(bootimage-generator-lflags) $(lflags) -o $(@)
 endif
 
 $(dynamic-library): $(vm-objects) $(dynamic-object) $(classpath-objects) \
@@ -1265,10 +1500,12 @@ $(dynamic-library): $(vm-objects) $(dynamic-object) $(classpath-objects) \
 		$(classpath-libraries) $(javahome-object) $(boot-javahome-object) \
 		$(lzma-decode-objects)
 	@echo "linking $(@)"
-ifdef msvc
+ifdef ms_cl_compiler
 	$(ld) $(shared) $(lflags) $(^) -out:$(@) -PDB:$(@).pdb \
-		-IMPLIB:$(build)/$(name).lib -MANIFESTFILE:$(@).manifest
-	$(mt) -manifest $(@).manifest -outputresource:"$(@);2"
+		-IMPLIB:$(build)/$(name).lib $(manifest-flags)
+ifdef mt
+	$(mt) -nologo -manifest $(@).manifest -outputresource:"$(@);2"
+endif
 else
 	$(ld) $(^) $(version-script-flag) $(soname-flag) \
 		$(shared) $(lflags) $(bootimage-lflags) \
@@ -1280,11 +1517,13 @@ endif
 # Ubuntu 11.10 which may be fixable without disabling LTO.
 $(executable-dynamic): $(driver-dynamic-objects) $(dynamic-library)
 	@echo "linking $(@)"
-ifdef msvc
+ifdef ms_cl_compiler
 	$(ld) $(lflags) -LIBPATH:$(build) -DEFAULTLIB:$(name) \
-		-PDB:$(@).pdb -IMPLIB:$(@).lib $(driver-dynamic-objects) -out:$(@) \
-		-MANIFESTFILE:$(@).manifest
-	$(mt) -manifest $(@).manifest -outputresource:"$(@);1"
+		-PDB:$(@).pdb -IMPLIB:$(@).lib $(driver-dynamic-objects) \
+		-out:$(@) $(manifest-flags)
+ifdef mt
+	$(mt) -nologo -manifest $(@).manifest -outputresource:"$(@);1"
+endif
 else
 	$(ld) $(driver-dynamic-objects) -L$(build) -ljvm $(lflags) $(no-lto) -o $(@)
 endif
diff --git a/src/arm.h b/src/arm.h
index 7e7a4d61dd..adfd92b4ad 100644
--- a/src/arm.h
+++ b/src/arm.h
@@ -71,33 +71,53 @@ namespace vm {
 inline void
 trap()
 {
+#ifdef _MSC_VER
+  __debugbreak();
+#else
   asm("bkpt");
+#endif
 }
 
+#ifndef _MSC_VER
 inline void
 memoryBarrier()
 {
   asm("nop");
 }
+#endif
 
 inline void
 storeStoreMemoryBarrier()
 {
+#ifdef _MSC_VER
+  _ReadWriteBarrier();
+#else
   memoryBarrier();
+#endif
 }
 
 inline void
 storeLoadMemoryBarrier()
 {
+#ifdef _MSC_VER
+  MemoryBarrier();
+#else
   memoryBarrier();
+#endif
 }
 
 inline void
 loadMemoryBarrier()
 {
+#ifdef _MSC_VER
+  _ReadWriteBarrier();
+#else
   memoryBarrier();
+#endif
 }
 
+#if defined(AVIAN_PROCESS_compile)
+
 #if defined(__ANDROID__)
 // http://code.google.com/p/android/issues/detail?id=1803
 extern "C" void __clear_cache (void *beg __attribute__((__unused__)), void *end __attribute__((__unused__)));
@@ -116,6 +136,8 @@ syncInstructionCache(const void* start, unsigned size)
 #endif
 }
 
+#endif // AVIAN_PROCESS_compile
+
 #ifndef __APPLE__
 typedef int (__kernel_cmpxchg_t)(int oldval, int newval, int *ptr);
 #  define __kernel_cmpxchg (*(__kernel_cmpxchg_t *)0xffff0fc0)
@@ -160,7 +182,7 @@ dynamicCall(void* function, uintptr_t* arguments, uint8_t* argumentTypes,
   unsigned vfpIndex = 0;
   unsigned vfpBackfillIndex UNUSED = 0;
 
-  uintptr_t stack[(argumentCount * 8) / BytesPerWord]; // is > argumentSize to account for padding
+  uintptr_t* stack = new uintptr_t[(argumentCount * 8) / BytesPerWord]; // is > argumentSize to account for padding
   unsigned stackIndex = 0;
 
   unsigned ai = 0;
@@ -250,10 +272,12 @@ dynamicCall(void* function, uintptr_t* arguments, uint8_t* argumentTypes,
   }
 
   unsigned stackSize = stackIndex*BytesPerWord + ((stackIndex & 1) << 2);
-  return vmNativeCall
+  auto retVal = vmNativeCall
     (function, stackSize, stack, stackIndex * BytesPerWord,
      (gprIndex ? gprTable : 0),
      (vfpIndex ? vfpTable : 0), returnType);
+  delete[] stack;
+  return retVal;
 }
 
 } // namespace vm
diff --git a/src/arm.masm b/src/arm.masm
new file mode 100644
index 0000000000..8fc09eb875
--- /dev/null
+++ b/src/arm.masm
@@ -0,0 +1,77 @@
+	AREA text, CODE, ARM
+	
+	EXPORT vmNativeCall [FUNC]
+vmNativeCall
+		;  arguments:
+		;  r0 -> r4       : function
+		;  r1 -> r5       : stackTotal
+		;  r2             : memoryTable
+		;  r3             : memoryCount
+		;  [sp, #0] -> r6 : gprTable
+
+		mov   ip, sp           ; save stack frame
+		stmfd sp!, {r4-r6, lr} ; save clobbered non-volatile regs
+
+		; mv args into non-volatile regs
+		mov   r4, r0
+		mov   r5, r1
+		ldr   r6, [ip]
+
+		; setup stack arguments if necessary
+		sub   sp, sp, r5 ; allocate stack
+		mov   ip, sp
+loop
+		tst   r3, r3
+		ldrne r0, [r2], #4
+		strne r0, [ip], #4
+		subne r3, r3, #4
+		bne   loop
+
+		; setup argument registers if necessary
+		tst     r6, r6
+		ldmneia r6, {r0-r3}
+
+		blx   r4         ; call function
+		add   sp, sp, r5 ; deallocate stack
+
+		ldmfd sp!, {r4-r6, pc} ; restore non-volatile regs and return
+
+	EXPORT vmJump [FUNC]
+vmJump
+		mov   lr, r0
+		ldr   r0, [sp]
+		ldr   r1, [sp, #4]
+		mov   sp, r2
+		mov   r8, r3
+		bx    lr
+
+CHECKPOINT_THREAD EQU 4
+CHECKPOINT_STACK EQU 24
+
+	EXPORT vmRun [FUNC]
+vmRun
+		; r0: function
+		; r1: arguments
+		; r2: checkpoint
+		stmfd sp!, {r4-r11, lr}
+		; align stack
+		sub   sp, sp, #12
+
+		str   sp, [r2, #CHECKPOINT_STACK]
+
+		mov   r12, r0
+		ldr   r0, [r2, #CHECKPOINT_THREAD]
+
+		blx   r12
+
+	EXPORT vmRun_returnAddress [FUNC]
+vmRun_returnAddress
+		add   sp, sp, #12
+		ldmfd sp!, {r4-r11, lr}
+		bx    lr
+
+	EXPORT vmTrap [FUNC]
+vmTrap
+		bkpt 3
+
+	END
\ No newline at end of file
diff --git a/src/binaryToObject/pe.cpp b/src/binaryToObject/pe.cpp
index 8d5d5fc444..186e491447 100644
--- a/src/binaryToObject/pe.cpp
+++ b/src/binaryToObject/pe.cpp
@@ -17,13 +17,17 @@
 
 namespace {
 
-#define IMAGE_SIZEOF_SHORT_NAME 8
+// --- winnt.h ----
+#define IMAGE_SIZEOF_SHORT_NAME              8
 
-#define IMAGE_FILE_RELOCS_STRIPPED 1
-#define IMAGE_FILE_LINE_NUMS_STRIPPED 4
-#define IMAGE_FILE_MACHINE_AMD64 0x8664
-#define IMAGE_FILE_MACHINE_I386 0x014c
-#define IMAGE_FILE_32BIT_MACHINE 256
+#define IMAGE_FILE_RELOCS_STRIPPED           0x0001  // Relocation info stripped from file.
+#define IMAGE_FILE_LINE_NUMS_STRIPPED        0x0004  // Line nunbers stripped from file.
+#define IMAGE_FILE_MACHINE_AMD64             0x8664  // AMD64 (K8)
+#define IMAGE_FILE_MACHINE_I386              0x014c  // Intel 386.
+#define IMAGE_FILE_MACHINE_ARM               0x01c0  // ARM Little-Endian
+#define IMAGE_FILE_MACHINE_THUMB             0x01c2  // ARM Thumb/Thumb-2 Little-Endian
+#define IMAGE_FILE_MACHINE_ARMNT             0x01c4  // ARM Thumb-2 Little-Endian
+#define IMAGE_FILE_32BIT_MACHINE             0x0100  // 32 bit word machine.
 
 #define IMAGE_SCN_ALIGN_1BYTES 0x100000
 #define IMAGE_SCN_ALIGN_2BYTES 0x200000
@@ -73,6 +77,7 @@ struct IMAGE_SYMBOL {
   uint8_t StorageClass;
   uint8_t NumberOfAuxSymbols;
 } __attribute__((packed));
+// --- winnt.h ----
 
 inline unsigned
 pad(unsigned n)
@@ -82,7 +87,7 @@ pad(unsigned n)
 
 using namespace avian::tools;
 
-template<unsigned BytesPerWord>
+template<unsigned BytesPerWord, PlatformInfo::Architecture Architecture>
 class WindowsPlatform : public Platform {
 public:
 
@@ -202,12 +207,15 @@ public:
     int machine;
     int machineMask;
 
-    if (BytesPerWord == 8) {
+    if (Architecture == PlatformInfo::x86_64) {
       machine = IMAGE_FILE_MACHINE_AMD64;
       machineMask = 0;
-    } else { // if (BytesPerWord == 8)
+    } else if (Architecture == PlatformInfo::x86) {
       machine = IMAGE_FILE_MACHINE_I386;
       machineMask = IMAGE_FILE_32BIT_MACHINE;
+    } else if (Architecture == PlatformInfo::Arm) {
+      machine = IMAGE_FILE_MACHINE_ARMNT;
+      machineMask = IMAGE_FILE_32BIT_MACHINE;
     }
 
     int sectionMask;
@@ -269,10 +277,11 @@ public:
   }
 
   WindowsPlatform():
-    Platform(PlatformInfo(PlatformInfo::Pe, BytesPerWord == 4 ? PlatformInfo::x86 : PlatformInfo::x86_64)) {}
+    Platform(PlatformInfo(PlatformInfo::Pe, Architecture)) {}
 };
 
-WindowsPlatform<4> windows32Platform;
-WindowsPlatform<8> windows64Platform;
+WindowsPlatform<4, PlatformInfo::x86> windows32Platform;
+WindowsPlatform<8, PlatformInfo::x86_64> windows64Platform;
+WindowsPlatform<4, PlatformInfo::Arm> windowsRtPlatform; // Windows Phone 8 and Windows RT
 
 } // namespace
diff --git a/src/bootimage.cpp b/src/bootimage.cpp
index f82e73f9f5..ec04196ca0 100644
--- a/src/bootimage.cpp
+++ b/src/bootimage.cpp
@@ -342,7 +342,7 @@ makeCodeImage(Thread* t, Zone* zone, BootImage* image, uint8_t* code,
 
         unsigned count = s.read2() - 1;
         if (count) {
-          Type types[count + 2];
+          Type* types = new Type[count + 2];
           types[0] = Type_object;
           types[1] = Type_intptr_t;
 
@@ -410,6 +410,9 @@ makeCodeImage(Thread* t, Zone* zone, BootImage* image, uint8_t* code,
             (t, typeMaps, hashMapFind
              (t, root(t, Machine::PoolMap), c, objectHash, objectEqual), array,
              objectHash);
+
+          delete[] types;
+          types = 0;
         }
       }
 
@@ -420,7 +423,7 @@ makeCodeImage(Thread* t, Zone* zone, BootImage* image, uint8_t* code,
         object fields = allFields(t, typeMaps, c, &count, &array);
         PROTECT(t, fields);
 
-        Field memberFields[count + 1];
+        Field* memberFields = new Field[count + 1];
 
         unsigned memberIndex;
         unsigned buildMemberOffset;
@@ -454,7 +457,7 @@ makeCodeImage(Thread* t, Zone* zone, BootImage* image, uint8_t* code,
 
         const unsigned StaticHeader = 3;
 
-        Field staticFields[count + StaticHeader];
+        Field* staticFields = new Field[count + StaticHeader];
         
         init(new (staticFields) Field, Type_object, 0, BytesPerWord, 0,
              TargetBytesPerWord);
@@ -586,6 +589,12 @@ makeCodeImage(Thread* t, Zone* zone, BootImage* image, uint8_t* code,
           hashMapInsert
             (t, typeMaps, classStaticTable(t, c), array, objectHash);
         }
+
+        delete[] memberFields;
+        memberFields = 0;
+
+        delete[] staticFields;
+        staticFields = 0;
       }
     }
   }
@@ -1334,7 +1343,7 @@ writeBootImage2(Thread* t, OutputStream* bootimageOutput, OutputStream* codeOutp
       }
       ++ count;
 
-      Field fields[count];
+      Field* fields = new Field[count];
 
       init(new (fields) Field, Type_object, 0, BytesPerWord, 0,
            TargetBytesPerWord);
@@ -1462,6 +1471,9 @@ writeBootImage2(Thread* t, OutputStream* bootimageOutput, OutputStream* codeOutp
       hashMapInsert
         (t, typeMaps, vm::type(t, static_cast<Machine::Type>(i)), array,
          objectHash);
+
+      delete[] fields;
+      fields = 0;
     }
 
     constants = makeCodeImage
@@ -1646,10 +1658,10 @@ writeBootImage2(Thread* t, OutputStream* bootimageOutput, OutputStream* codeOutp
     
     Platform* platform = Platform::getPlatform(PlatformInfo((PlatformInfo::Format)AVIAN_TARGET_FORMAT, (PlatformInfo::Architecture)AVIAN_TARGET_ARCH));
 
-    // if(!platform) {
-    //   fprintf(stderr, "unsupported platform: %s/%s\n", os, architecture);
-    //   return false;
-    // }
+    if(!platform) {
+      fprintf(stderr, "unsupported platform: target-format = %d / target-arch = %d\n", AVIAN_TARGET_FORMAT, AVIAN_TARGET_ARCH);
+      abort();
+    }
 
     SymbolInfo bootimageSymbols[] = {
       SymbolInfo(0, bootimageStart),
@@ -1768,7 +1780,7 @@ bool ArgParser::parse(int ac, const char** av) {
       }
       bool found = false;
       for(Arg* arg = first; arg; arg = arg->next) {
-        if(strcmp(arg->name,  &av[i][1]) == 0) {
+        if(::strcmp(arg->name, &av[i][1]) == 0) {
           found = true;
           if (arg->desc == 0) {
             arg->value = "true";
@@ -1905,20 +1917,26 @@ public:
       exit(1);
     }
 
+#   if AVIAN_TARGET_FORMAT != AVIAN_FORMAT_PE
+#     define SYMBOL_PREFIX "_"
+#   else
+#     define SYMBOL_PREFIX
+#   endif
+
     if(!bootimageStart) {
-      bootimageStart = strdup("_binary_bootimage_bin_start");
+      bootimageStart = strdup(SYMBOL_PREFIX"binary_bootimage_bin_start");
     }
 
     if(!bootimageEnd) {
-      bootimageEnd = strdup("_binary_bootimage_bin_end");
+      bootimageEnd = strdup(SYMBOL_PREFIX"binary_bootimage_bin_end");
     }
 
     if(!codeimageStart) {
-      codeimageStart = strdup("_binary_codeimage_bin_start");
+      codeimageStart = strdup(SYMBOL_PREFIX"binary_codeimage_bin_start");
     }
 
     if(!codeimageEnd) {
-      codeimageEnd = strdup("_binary_codeimage_bin_end");
+      codeimageEnd = strdup(SYMBOL_PREFIX"binary_codeimage_bin_end");
     }
 
   }
diff --git a/src/common.h b/src/common.h
index adab2f587f..c99f23410e 100644
--- a/src/common.h
+++ b/src/common.h
@@ -94,7 +94,13 @@ typedef int64_t intptr_t;
 typedef uint64_t uintptr_t;
 #    define UINT64_C(x) x##L
 #    define ARCH_x86_64
-@    define BYTES_PER_WORD 8
+#    define BYTES_PER_WORD 8
+#  elif defined _M_ARM_FP
+typedef int32_t intptr_t;
+typedef uint32_t uintptr_t;
+#    define UINT64_C(x) x##LL
+#    define ARCH_arm
+#    define BYTES_PER_WORD 4
 #  else
 #    error "unsupported architecture"
 #  endif
diff --git a/src/interpret.cpp b/src/interpret.cpp
index 4a324fd084..9399e96657 100644
--- a/src/interpret.cpp
+++ b/src/interpret.cpp
@@ -18,7 +18,7 @@
 
 using namespace vm;
 
-namespace {
+namespace local {
 
 const unsigned FrameBaseOffset = 0;
 const unsigned FrameNextOffset = 1;
@@ -2321,7 +2321,7 @@ interpret3(Thread* t, const int base)
     object class_ = resolveClassInPool(t, frameMethod(t, frame), index - 1);
     PROTECT(t, class_);
 
-    int32_t counts[dimensions];
+    int32_t* counts = new int32_t[dimensions];
     for (int i = dimensions - 1; i >= 0; --i) {
       counts[i] = popInt(t);
       if (UNLIKELY(counts[i] < 0)) {
@@ -2338,6 +2338,9 @@ interpret3(Thread* t, const int base)
     populateMultiArray(t, array, counts, 0, dimensions);
 
     pushObject(t, array);
+
+    delete[] counts;
+    counts = 0;
   } goto loop;
 
   case new_: {
@@ -3100,7 +3103,7 @@ class MyProcessor: public Processor {
       (&byteArrayBody(t, methodSpec(t, method), 0));
     pushArguments(t, this_, spec, arguments);
 
-    return ::invoke(t, method);
+    return local::invoke(t, method);
   }
 
   virtual object
@@ -3124,7 +3127,7 @@ class MyProcessor: public Processor {
       (&byteArrayBody(t, methodSpec(t, method), 0));
     pushArguments(t, this_, spec, arguments);
 
-    return ::invoke(t, method);
+    return local::invoke(t, method);
   }
 
   virtual object
@@ -3148,7 +3151,7 @@ class MyProcessor: public Processor {
       (&byteArrayBody(t, methodSpec(t, method), 0));
     pushArguments(t, this_, spec, indirectObjects, arguments);
 
-    return ::invoke(t, method);
+    return local::invoke(t, method);
   }
 
   virtual object
@@ -3174,7 +3177,7 @@ class MyProcessor: public Processor {
 
     assert(t, ((methodFlags(t, method) & ACC_STATIC) == 0) xor (this_ == 0));
 
-    return ::invoke(t, method);
+    return local::invoke(t, method);
   }
 
   virtual object getStackTrace(vm::Thread* t, vm::Thread*) {
@@ -3254,8 +3257,8 @@ namespace vm {
 Processor*
 makeProcessor(System* system, Allocator* allocator, bool)
 {
-  return new (allocator->allocate(sizeof(MyProcessor)))
-    MyProcessor(system, allocator);
+  return new (allocator->allocate(sizeof(local::MyProcessor)))
+    local::MyProcessor(system, allocator);
 }
 
 } // namespace vm
diff --git a/src/machine.h b/src/machine.h
index 2924a13fb7..420a0192cb 100644
--- a/src/machine.h
+++ b/src/machine.h
@@ -1325,6 +1325,9 @@ checkDaemon(Thread* t);
 object&
 root(Thread* t, Machine::Root root);
 
+#if defined(_MSC_VER) && (defined(_M_IX86) || defined(_M_X64))
+#  define vmRun vmRun_
+#endif
 extern "C" uint64_t
 vmRun(uint64_t (*function)(Thread*, uintptr_t*), uintptr_t* arguments,
       void* checkpoint);
diff --git a/src/system.h b/src/system.h
index c36aefacd9..14a29c7272 100644
--- a/src/system.h
+++ b/src/system.h
@@ -97,11 +97,13 @@ class System {
     virtual void disposeAll() = 0;
   };
 
+#if defined(AVIAN_PROCESS_compile)
   class SignalHandler {
    public:
     virtual bool handleSignal(void** ip, void** frame, void** stack, 
                               void** thread) = 0;
   };
+#endif
 
   class MonitorResource {
    public:
@@ -121,17 +123,21 @@ class System {
   virtual bool success(Status) = 0;
   virtual void* tryAllocate(unsigned sizeInBytes) = 0;
   virtual void free(const void* p) = 0;
+#if defined(AVIAN_PROCESS_compile)
   virtual void* tryAllocateExecutable(unsigned sizeInBytes) = 0;
   virtual void freeExecutable(const void* p, unsigned sizeInBytes) = 0;
+#endif
   virtual Status attach(Runnable*) = 0;
   virtual Status start(Runnable*) = 0;
   virtual Status make(Mutex**) = 0;
   virtual Status make(Monitor**) = 0;
   virtual Status make(Local**) = 0;
+#if defined(AVIAN_PROCESS_compile)
   virtual Status handleSegFault(SignalHandler* handler) = 0;
   virtual Status handleDivideByZero(SignalHandler* handler) = 0;
   virtual Status visit(Thread* thread, Thread* target,
                        ThreadVisitor* visitor) = 0;
+#endif
   virtual uint64_t call(void* function, uintptr_t* arguments, uint8_t* types,
                         unsigned count, unsigned size,
                         unsigned returnType) = 0;
diff --git a/src/windows.cpp b/src/windows.cpp
index 532b66e161..2d8c4c16c4 100644
--- a/src/windows.cpp
+++ b/src/windows.cpp
@@ -26,6 +26,71 @@
 #include "arch.h"
 #include "system.h"
 
+#if defined(WINAPI_FAMILY)
+
+#if !WINAPI_FAMILY_PARTITION(WINAPI_PARTITION_DESKTOP)
+
+#define WaitForSingleObject(hHandle, dwMilliseconds) \
+  WaitForSingleObjectEx((hHandle), (dwMilliseconds), FALSE)
+
+#define CreateEvent(lpEventAttributes, bManualReset, bInitialState, lpName) \
+  CreateEventEx((lpEventAttributes), (lpName), ((bManualReset)?CREATE_EVENT_MANUAL_RESET:0)|((bInitialState)?CREATE_EVENT_INITIAL_SET:0), EVENT_MODIFY_STATE)
+
+#define CreateMutex(lpEventAttributes, bInitialOwner, lpName) \
+  CreateMutexEx((lpEventAttributes), (lpName), (bInitialOwner)?CREATE_MUTEX_INITIAL_OWNER:0, MUTEX_MODIFY_STATE)
+
+#include "thread-emulation.h"
+
+#endif
+
+#if WINAPI_FAMILY_PARTITION(WINAPI_PARTITION_PHONE)
+// Headers in Windows Phone 8 DevKit contain severe error, so let's define needed functions on our own
+extern "C"
+{
+WINBASEAPI
+_Ret_maybenull_
+HANDLE
+WINAPI
+CreateFileMappingFromApp(
+    _In_ HANDLE hFile,
+    _In_opt_ PSECURITY_ATTRIBUTES SecurityAttributes,
+    _In_ ULONG PageProtection,
+    _In_ ULONG64 MaximumSize,
+    _In_opt_ PCWSTR Name
+    );
+
+WINBASEAPI
+_Ret_maybenull_  __out_data_source(FILE)
+PVOID
+WINAPI
+MapViewOfFileFromApp(
+    _In_ HANDLE hFileMappingObject,
+    _In_ ULONG DesiredAccess,
+    _In_ ULONG64 FileOffset,
+    _In_ SIZE_T NumberOfBytesToMap
+    );
+
+WINBASEAPI
+BOOL
+WINAPI
+UnmapViewOfFile(
+    _In_ LPCVOID lpBaseAddress
+    );
+}
+#endif // WINAPI_FAMILY_PARTITION(WINAPI_PARTITION_PHONE)
+
+#else
+
+#ifndef WINAPI_PARTITION_DESKTOP
+#define WINAPI_PARTITION_DESKTOP 1
+#endif
+
+#ifndef WINAPI_FAMILY_PARTITION
+#define WINAPI_FAMILY_PARTITION(x) (x)
+#endif
+
+#endif
+
 #define ACQUIRE(s, x) MutexResource MAKE_NAME(mutexResource_) (s, x)
 
 using namespace vm;
@@ -49,16 +114,20 @@ class MutexResource {
   HANDLE m;
 };
 
+#if defined(AVIAN_PROCESS_compile)
 const unsigned SegFaultIndex = 0;
 const unsigned DivideByZeroIndex = 1;
 
 const unsigned HandlerCount = 2;
+#endif
 
 class MySystem;
 MySystem* system;
 
+#if defined(AVIAN_PROCESS_compile)
 LONG CALLBACK
 handleException(LPEXCEPTION_POINTERS e);
+#endif
 
 DWORD WINAPI
 run(void* r)
@@ -559,18 +628,22 @@ class MySystem: public System {
   };
 
   MySystem(const char* crashDumpDirectory):
+#if defined(AVIAN_PROCESS_compile)
     oldHandler(0),
+#endif
     crashDumpDirectory(crashDumpDirectory)
   {
     expect(this, system == 0);
     system = this;
 
+#if defined(AVIAN_PROCESS_compile)
     memset(handlers, 0, sizeof(handlers));
+#endif
 
     mutex = CreateMutex(0, false, 0);
     assert(this, mutex);
   }
-
+#if defined(AVIAN_PROCESS_compile)
   bool findHandler() {
     for (unsigned i = 0; i < HandlerCount; ++i) {
       if (handlers[i]) return true;
@@ -578,6 +651,7 @@ class MySystem: public System {
     return false;
   }
 
+  //TODO: http://msdn.microsoft.com/en-us/library/windowsphone/develop/system.windows.application.unhandledexception(v=vs.105).aspx
   int registerHandler(System::SignalHandler* handler, int index) {
     if (handler) {
       handlers[index] = handler;
@@ -609,7 +683,7 @@ class MySystem: public System {
       return 1;
     }
   }
-
+#endif
   virtual void* tryAllocate(unsigned sizeInBytes) {
     return malloc(sizeInBytes);
   }
@@ -618,6 +692,7 @@ class MySystem: public System {
     if (p) ::free(const_cast<void*>(p));
   }
 
+  #if defined(AVIAN_PROCESS_compile)
   virtual void* tryAllocateExecutable(unsigned sizeInBytes) {
     return VirtualAlloc
       (0, sizeInBytes, MEM_COMMIT | MEM_RESERVE, PAGE_EXECUTE_READWRITE);
@@ -627,6 +702,7 @@ class MySystem: public System {
     int r UNUSED = VirtualFree(const_cast<void*>(p), 0, MEM_RELEASE);
     assert(this, r);
   }
+  #endif
 
   virtual bool success(Status s) {
     return s == 0;
@@ -666,6 +742,7 @@ class MySystem: public System {
     return 0;
   }
 
+#if defined(AVIAN_PROCESS_compile)
   virtual Status handleSegFault(SignalHandler* handler) {
     return registerHandler(handler, SegFaultIndex);
   }
@@ -710,6 +787,7 @@ class MySystem: public System {
 
     return (success ? 0 : 1);
   }
+#endif
 
   virtual uint64_t call(void* function, uintptr_t* arguments, uint8_t* types,
                         unsigned count, unsigned size, unsigned returnType)
@@ -719,15 +797,39 @@ class MySystem: public System {
 
   virtual Status map(System::Region** region, const char* name) {
     Status status = 1;
-    
+#if !defined(WINAPI_FAMILY) || WINAPI_FAMILY_PARTITION(WINAPI_PARTITION_DESKTOP)
     HANDLE file = CreateFile(name, FILE_READ_DATA, FILE_SHARE_READ, 0,
                              OPEN_EXISTING, 0, 0);
+#else
+    size_t nameLen = strlen(name);
+    wchar_t* wideName = new wchar_t[nameLen + 1];
+    size_t convertedChars = 0;
+    mbstowcs_s(&convertedChars, wideName, nameLen + 1, name, nameLen);
+    HANDLE file = CreateFile2(wideName, GENERIC_READ, FILE_SHARE_READ,
+                             OPEN_EXISTING, 0);
+    delete[] wideName;
+#endif
     if (file != INVALID_HANDLE_VALUE) {
+#if !defined(WINAPI_FAMILY) || WINAPI_FAMILY_PARTITION(WINAPI_PARTITION_DESKTOP)
       unsigned size = GetFileSize(file, 0);
+#else
+      FILE_STANDARD_INFO info;
+      unsigned size = INVALID_FILE_SIZE;
+      if(GetFileInformationByHandleEx(file,  FileStandardInfo, &info, sizeof(info)))
+        size = info.EndOfFile.QuadPart;
+#endif
       if (size != INVALID_FILE_SIZE) {
+#if !defined(WINAPI_FAMILY) || WINAPI_FAMILY_PARTITION(WINAPI_PARTITION_DESKTOP)
         HANDLE mapping = CreateFileMapping(file, 0, PAGE_READONLY, 0, size, 0);
+#else
+        HANDLE mapping = CreateFileMappingFromApp(file, 0, PAGE_READONLY, size, 0);
+#endif
         if (mapping) {
+#if !defined(WINAPI_FAMILY) || WINAPI_FAMILY_PARTITION(WINAPI_PARTITION_DESKTOP)
           void* data = MapViewOfFile(mapping, FILE_MAP_READ, 0, 0, 0);
+#else
+          void* data = MapViewOfFileFromApp(mapping, FILE_MAP_READ, 0, 0);
+#endif
           if (data) {
             *region = new (allocate(this, sizeof(Region)))
               Region(this, static_cast<uint8_t*>(data), size, file, mapping);
@@ -757,7 +859,12 @@ class MySystem: public System {
     memcpy(RUNTIME_ARRAY_BODY(buffer) + length, "\\*", 3);
 
     Directory* d = new (allocate(this, sizeof(Directory))) Directory(this);
+
+#if !defined(WINAPI_FAMILY) || WINAPI_FAMILY_PARTITION(WINAPI_PARTITION_DESKTOP)
     d->handle = FindFirstFile(RUNTIME_ARRAY_BODY(buffer), &(d->data));
+#else
+    d->handle = FindFirstFileEx(RUNTIME_ARRAY_BODY(buffer), FindExInfoStandard, &(d->data), FindExSearchNameMatch, 0, 0);
+#endif
     if (d->handle == INVALID_HANDLE_VALUE) {
       d->dispose();
     } else {
@@ -797,6 +904,7 @@ class MySystem: public System {
   }
 
   virtual const char* toAbsolutePath(Allocator* allocator, const char* name) {
+#if !defined(WINAPI_FAMILY) || WINAPI_FAMILY_PARTITION(WINAPI_PARTITION_DESKTOP)
     if (strncmp(name, "//", 2) == 0
         or strncmp(name, "\\\\", 2) == 0
         or strncmp(name + 1, ":/", 2) == 0
@@ -808,6 +916,11 @@ class MySystem: public System {
       GetCurrentDirectory(MAX_PATH, buffer);
       return append(allocator, buffer, "\\", name);
     }
+#else
+    //TODO:http://lunarfrog.com/blog/2012/05/21/winrt-folders-access/
+    //Windows.ApplicationModel.Package.Current.InstalledLocation
+    return name;
+#endif
   }
 
   virtual Status load(System::Library** lib,
@@ -816,9 +929,23 @@ class MySystem: public System {
     HMODULE handle;
     unsigned nameLength = (name ? strlen(name) : 0);
     if (name) {
+#if !defined(WINAPI_FAMILY) || WINAPI_FAMILY_PARTITION(WINAPI_PARTITION_DESKTOP)
       handle = LoadLibrary(name);
+#else
+      size_t nameLen = strlen(name);
+      wchar_t* wideName = new wchar_t[nameLen + 1];
+	  size_t convertedChars = 0;
+      mbstowcs_s(&convertedChars, wideName, nameLen + 1, name, nameLen);
+      handle = LoadPackagedLibrary(wideName, 0);
+      delete[] wideName;
+#endif
     } else {
+#if !defined(WINAPI_FAMILY) || WINAPI_FAMILY_PARTITION(WINAPI_PARTITION_DESKTOP)
       handle = GetModuleHandle(0);
+#else
+      // Most of WinRT/WP8 applications can not host native object files inside main executable
+      assert(this, false);
+#endif
     }
  
     if (handle) {
@@ -866,7 +993,11 @@ class MySystem: public System {
   }
 
   virtual void yield() {
+#if !defined(WINAPI_FAMILY) || WINAPI_FAMILY_PARTITION(WINAPI_PARTITION_DESKTOP)
     SwitchToThread();
+#else
+    YieldProcessor();
+#endif
   }
 
   virtual void exit(int code) {
@@ -886,11 +1017,15 @@ class MySystem: public System {
   }
 
   HANDLE mutex;
+#if defined(AVIAN_PROCESS_compile)
   SignalHandler* handlers[HandlerCount];
   LPTOP_LEVEL_EXCEPTION_FILTER oldHandler;
+#endif
   const char* crashDumpDirectory;
 };
 
+#if defined(AVIAN_PROCESS_compile)
+
 #pragma pack(push,4)
 struct MINIDUMP_EXCEPTION_INFORMATION {
   DWORD thread;
@@ -1005,6 +1140,8 @@ handleException(LPEXCEPTION_POINTERS e)
   return EXCEPTION_CONTINUE_SEARCH;
 }
 
+#endif
+
 } // namespace
 
 namespace vm {
diff --git a/src/x86.masm b/src/x86.masm
new file mode 100644
index 0000000000..715669f8c1
--- /dev/null
+++ b/src/x86.masm
@@ -0,0 +1,166 @@
+comment #
+   Copyright (c) 2008-2011, Avian Contributors
+
+   Permission to use, copy, modify, and/or distribute this software
+   for any purpose with or without fee is hereby granted, provided
+   that the above copyright notice and this permission notice appear
+   in all copies.
+   
+   There is NO WARRANTY for this software.  See license.txt for
+   details.
+#
+
+.586
+.MODEL FLAT, C 
+ 
+VOID_TYPE equ 0
+INT8_TYPE equ 1
+INT16_TYPE equ 2
+INT32_TYPE equ 3
+INT64_TYPE equ 4
+FLOAT_TYPE equ 5
+DOUBLE_TYPE equ 6
+POINTER_TYPE equ 7
+
+CHECKPOINT_THREAD equ 4
+CHECKPOINT_STACK equ 24
+CHECKPOINT_BASE equ 28
+
+_TEXT SEGMENT
+
+public C detectFeature
+detectFeature:
+	push ebp
+	mov ebp,esp
+	push edx
+	push ecx
+	push ebx
+	push esi
+	push edi
+	mov esi,ds:dword ptr[12+ebp]
+	mov edi,ds:dword ptr[8+ebp]
+	mov eax,1
+	cpuid
+	and edx,esi
+	and ecx,edi
+	or ecx,edx
+	test ecx,ecx
+	je LNOSSE
+	mov eax,1
+	jmp LSSEEND
+
+LNOSSE:
+	mov eax,0
+
+LSSEEND:
+	pop edi
+	pop esi
+	pop ebx
+	pop ecx
+	pop edx
+	mov esp,ebp
+	pop ebp
+	ret
+
+public C vmNativeCall
+vmNativeCall:
+	push ebp
+	mov ebp,esp
+	mov ecx,ds:dword ptr[16+ebp]
+	sub esp,ecx
+	mov ecx,0
+	jmp Ltest
+
+Lloop:
+	mov eax,ecx
+	mov edx,ecx
+	add edx,esp
+	add eax,ds:dword ptr[12+ebp]
+	mov eax,ds:dword ptr[eax]
+	mov ds:dword ptr[edx],eax
+	add ecx,4
+
+Ltest:
+	cmp ecx,ds:dword ptr[16+ebp]
+	jb Lloop
+	call dword ptr[8+ebp]
+	mov ecx,ds:dword ptr[20+ebp]
+
+Lvoid:
+	cmp ecx,offset VOID_TYPE
+	jne Lint64
+	jmp Lexit
+
+Lint64:
+	cmp ecx,offset INT64_TYPE
+	jne Lfloat
+	jmp Lexit
+
+Lfloat:
+	cmp ecx,offset FLOAT_TYPE
+	jne Ldouble
+	fstp ds:dword ptr[8+ebp]
+	mov eax,ds:dword ptr[8+ebp]
+	jmp Lexit
+
+Ldouble:
+	cmp ecx,offset DOUBLE_TYPE
+	jne Lexit
+	fstp ds:dword ptr[8+ebp]
+	mov eax,ds:dword ptr[8+ebp]
+	mov edx,ds:dword ptr[12+ebp]
+
+Lexit:
+	mov esp,ebp
+	pop ebp
+	ret
+
+public C vmJump
+vmJump:
+	mov esi,ds:dword ptr[4+esp]
+	mov ebp,ds:dword ptr[8+esp]
+	mov ebx,ds:dword ptr[16+esp]
+	mov eax,ds:dword ptr[20+esp]
+	mov edx,ds:dword ptr[24+esp]
+	mov esp,ds:dword ptr[12+esp]
+	jmp esi
+
+VMRUN_FRAME_SIZE equ 24
+
+public C vmRun_
+vmRun_:
+	; 8(%ebp): function
+	; 12(%ebp): arguments
+	; 16(%ebp): checkpoint
+	push ebp
+	mov ebp,esp
+	sub esp,offset VMRUN_FRAME_SIZE
+
+	mov ds:dword ptr[8+esp],ebx
+	mov ds:dword ptr[12+esp],esi
+	mov ds:dword ptr[16+esp],edi
+
+	mov eax,ds:dword ptr[12+ebp]
+	mov ds:dword ptr[4+esp],eax
+
+	mov ecx,ds:dword ptr[16+ebp]
+	mov eax,ds:dword ptr[CHECKPOINT_THREAD+ecx]
+	mov ds:dword ptr[0+esp],eax
+
+	mov ds:dword ptr[CHECKPOINT_STACK+ecx],esp
+
+	call dword ptr[8+ebp]
+
+public C vmRun_returnAddress
+vmRun_returnAddress:
+
+	mov ebx,ds:dword ptr[8+esp]
+	mov esi,ds:dword ptr[12+esp]
+	mov edi,ds:dword ptr[16+esp]
+
+	add esp,offset VMRUN_FRAME_SIZE
+	pop ebp
+	ret
+ 
+_TEXT ENDS
+END
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