diff --git uppsrc/Core/Cpu.cpp uppsrc/Core/Cpu.cpp
--- uppsrc/Core/Cpu.cpp
+++ uppsrc/Core/Cpu.cpp
@@ -149,7 +149,7 @@ void EndianSwap(int *v, size_t count) ENDIAN_SWAP
 void EndianSwap(int64 *v, size_t count) ENDIAN_SWAP
 void EndianSwap(uint64 *v, size_t count) ENDIAN_SWAP
 
-#ifdef CPU_X86
+#if defined(CPU_X86) && defined(__SSE2__)
 void huge_memsetd(void *p, dword c, int len)
 { // bypasses the cache, good for >4MB
 	dword *t = (dword *)p;
diff --git uppsrc/Core/Ops.h uppsrc/Core/Ops.h
--- uppsrc/Core/Ops.h
+++ uppsrc/Core/Ops.h
@@ -342,9 +342,9 @@ inline bool FitsInInt64(double x)
 	return x >= -9223372036854775808.0 && x < 9223372036854775808.0;
 }
 
-#ifdef CPU_X86
+#if defined(CPU_X86) && defined(__SSE2__)
 
-#include <smmintrin.h>
+#include <emmintrin.h>
 
 void huge_memsetd(void *p, dword data, int len);