diff --git a/src/Reactor/LLVMReactor.cpp b/src/Reactor/LLVMReactor.cpp
index e6b4b94..d3da778 100644
--- a/src/Reactor/LLVMReactor.cpp
+++ b/src/Reactor/LLVMReactor.cpp
@@ -2141,6 +2141,14 @@
 		return UnpackLow(RValue<Byte8>(byte8), RValue<Byte8>(byte8));
 	}
 
+	RValue<Short4> Unpack(RValue<Byte4> x, RValue<Byte4> y)
+	{
+		Value *xx = Nucleus::createInsertElement(V(UndefValue::get(VectorType::get(Int::getType(), 2))), x.value, 0);
+		Value *yy = Nucleus::createInsertElement(V(UndefValue::get(VectorType::get(Int::getType(), 2))), y.value, 0);
+
+		return UnpackLow(As<Byte8>(xx), As<Byte8>(yy));
+	}
+
 	RValue<Short4> UnpackLow(RValue<Byte8> x, RValue<Byte8> y)
 	{
 		if(CPUID::supportsMMX2())
diff --git a/src/Reactor/Reactor.hpp b/src/Reactor/Reactor.hpp
index 74a3f6c..cfb005c 100644
--- a/src/Reactor/Reactor.hpp
+++ b/src/Reactor/Reactor.hpp
@@ -564,6 +564,7 @@
 	RValue<Byte8> AddSat(RValue<Byte8> x, RValue<Byte8> y);
 	RValue<Byte8> SubSat(RValue<Byte8> x, RValue<Byte8> y);
 	RValue<Short4> Unpack(RValue<Byte4> x);
+	RValue<Short4> Unpack(RValue<Byte4> x, RValue<Byte4> y);
 	RValue<Short4> UnpackLow(RValue<Byte8> x, RValue<Byte8> y);
 	RValue<Short4> UnpackHigh(RValue<Byte8> x, RValue<Byte8> y);
 	RValue<Int> SignMask(RValue<Byte8> x);
diff --git a/src/Reactor/SubzeroReactor.cpp b/src/Reactor/SubzeroReactor.cpp
index 9cd6fb8..5468cb9 100644
--- a/src/Reactor/SubzeroReactor.cpp
+++ b/src/Reactor/SubzeroReactor.cpp
@@ -40,8 +40,8 @@
 #include <Windows.h>
 #else
 #include <sys/mman.h>
-#if !defined(MAP_ANONYMOUS)
-#define MAP_ANONYMOUS MAP_ANON
+#if !defined(MAP_ANONYMOUS)
+#define MAP_ANONYMOUS MAP_ANON
 #endif
 #endif
 
@@ -2572,6 +2572,11 @@
 		return RValue<Short4>(Nucleus::createShuffleVector(x.value, x.value, shuffle));
 	}
 
+	RValue<Short4> Unpack(RValue<Byte4> x, RValue<Byte4> y)
+	{
+		return UnpackLow(As<Byte8>(x), As<Byte8>(y));
+	}
+
 	RValue<Short4> UnpackLow(RValue<Byte8> x, RValue<Byte8> y)
 	{
 		int shuffle[16] = {0, 16, 1, 17, 2, 18, 3, 19, 4, 20, 5, 21, 6, 22, 7, 23};   // Real type is v16i8