diff --git a/moo/lib/Makefile.am b/moo/lib/Makefile.am
index 6e5e8b4..f3d6fc9 100644
--- a/moo/lib/Makefile.am
+++ b/moo/lib/Makefile.am
@@ -41,7 +41,7 @@ pkginclude_HEADERS = \
 	moo-utl.h \
 	moo.h
 
-noinst_HEADERS = moo-prv.h
+noinst_HEADERS = moo-prv.h pack1.h unpack.h
 
 pkglib_LTLIBRARIES = libmoo.la
 libmoo_la_SOURCES = \
diff --git a/moo/lib/Makefile.in b/moo/lib/Makefile.in
index 070d964..511edc4 100644
--- a/moo/lib/Makefile.in
+++ b/moo/lib/Makefile.in
@@ -427,7 +427,7 @@ pkginclude_HEADERS = \
 	moo-utl.h \
 	moo.h
 
-noinst_HEADERS = moo-prv.h
+noinst_HEADERS = moo-prv.h pack1.h unpack.h
 pkglib_LTLIBRARIES = libmoo.la
 libmoo_la_SOURCES = \
 	bigint.c \
diff --git a/moo/lib/exec.c b/moo/lib/exec.c
index ebb6c13..8e5d3f5 100644
--- a/moo/lib/exec.c
+++ b/moo/lib/exec.c
@@ -3583,7 +3583,7 @@ static moo_pfrc_t pf_smptr_free (moo_t* moo, moo_ooi_t nargs)
 }
 
 
-#pragma pack(1)
+#include "pack1.h"
 struct st_int8_t    { moo_int8_t  v; };
 struct st_int16_t   { moo_int16_t v; };
 struct st_int32_t   { moo_int32_t v; };
@@ -3600,7 +3600,7 @@ struct st_uint64_t  { moo_uint64_t v; };
 struct st_int128_t   { moo_int128_t v; };
 struct st_uint128_t  { moo_uint128_t v; };
 #endif
-#pragma pack()
+#include "unpack.h"
 
 
 static MOO_INLINE moo_oop_t _fetch_raw_int (moo_t* moo, moo_int8_t* rawptr, moo_oow_t offset, int size)
diff --git a/moo/lib/pack1.h b/moo/lib/pack1.h
new file mode 100644
index 0000000..cbad10a
--- /dev/null
+++ b/moo/lib/pack1.h
@@ -0,0 +1,37 @@
+/*
+ * $Id$
+ *
+    Copyright (c) 2014-2017 Chung, Hyung-Hwan. All rights reserved.
+
+    Redistribution and use in source and binary forms, with or without
+    modification, are permitted provided that the following conditions
+    are met:
+    1. Redistributions of source code must retain the above copyright
+       notice, this list of conditions and the following disclaimer.
+    2. Redistributions in binary form must reproduce the above copyright
+       notice, this list of conditions and the following disclaimer in the
+       documentation and/or other materials provided with the distribution.
+
+    THIS SOFTWARE IS PROVIDED BY THE AUTHOR "AS IS" AND ANY EXPRESS OR
+    IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+    OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+    IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
+    INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+    NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+    DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+    THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+    (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+    THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#if defined(__GNUC__)
+#	pragma pack(1)
+#elif defined(__HP_aCC) || defined(__HP_cc)
+#	pragma PACK 1
+#elif defined(_MSC_VER) || (defined(__BORLANDC__) && (__BORLANDC__ >= 0x0500))
+#	pragma pack(push,1)
+#elif defined(__DECC)
+#	pragma pack(push,1)
+#else
+#	pragma pack(1)
+#endif
diff --git a/moo/lib/unpack.h b/moo/lib/unpack.h
new file mode 100644
index 0000000..5947c15
--- /dev/null
+++ b/moo/lib/unpack.h
@@ -0,0 +1,37 @@
+/*
+ * $Id$
+ *
+    Copyright (c) 2014-2017 Chung, Hyung-Hwan. All rights reserved.
+
+    Redistribution and use in source and binary forms, with or without
+    modification, are permitted provided that the following conditions
+    are met:
+    1. Redistributions of source code must retain the above copyright
+       notice, this list of conditions and the following disclaimer.
+    2. Redistributions in binary form must reproduce the above copyright
+       notice, this list of conditions and the following disclaimer in the
+       documentation and/or other materials provided with the distribution.
+
+    THIS SOFTWARE IS PROVIDED BY THE AUTHOR "AS IS" AND ANY EXPRESS OR
+    IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+    OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+    IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
+    INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+    NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+    DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+    THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+    (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+    THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#if defined(__GNUC__)
+#	pragma pack()
+#elif defined(__HP_aCC) || defined(__HP_cc)
+#	pragma PACK
+#elif defined(_MSC_VER) || (defined(__BORLANDC__) && (__BORLANDC__ >= 0x0500))
+#	pragma pack(pop)
+#elif defined(__DECC)
+#	pragma pack(pop)
+#else
+#	pragma pack()
+#endif