diff --git a/glx/unpack.h b/glx/unpack.h
index a4e6d7e84..738e79dc4 100644
--- a/glx/unpack.h
+++ b/glx/unpack.h
@@ -47,7 +47,7 @@
 ** Fetch a double from potentially unaligned memory.
 */
 #ifdef __GLX_ALIGN64
-#define __GLX_MEM_COPY(dst,src,n)	if (src != NULL && dst != NULL) memcpy(dst,src,n)
+#define __GLX_MEM_COPY(dst,src,n)	memmove(dst,src,n)
 #define __GLX_GET_DOUBLE(dst,src)	__GLX_MEM_COPY(&dst,src,8)
 #else
 #define __GLX_GET_DOUBLE(dst,src)	(dst) = *((GLdouble*)(src))
diff --git a/hw/dmx/glxProxy/unpack.h b/hw/dmx/glxProxy/unpack.h
index f34b6fd51..f4a957206 100644
--- a/hw/dmx/glxProxy/unpack.h
+++ b/hw/dmx/glxProxy/unpack.h
@@ -43,7 +43,7 @@
 ** Fetch a double from potentially unaligned memory.
 */
 #ifdef __GLX_ALIGN64
-#define __GLX_MEM_COPY(dst,src,n)	memcpy(dst,src,n)
+#define __GLX_MEM_COPY(dst,src,n)	memmove(dst,src,n)
 #define __GLX_GET_DOUBLE(dst,src)	__GLX_MEM_COPY(&dst,src,8)
 #else
 #define __GLX_GET_DOUBLE(dst,src)	(dst) = *((GLdouble*)(src))