diff --git a/libc/arch-arm/include/endian.h b/libc/arch-arm/include/endian.h
index 04204ed..e34872f 100644
--- a/libc/arch-arm/include/endian.h
+++ b/libc/arch-arm/include/endian.h
@@ -1,5 +1,86 @@
 /*	$OpenBSD: endian.h,v 1.3 2005/12/13 00:35:23 millert Exp $	*/
 
+/*
+ * Copyright (C) 2010 The Android Open Source Project
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *  * Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ *  * 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 COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "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
+ * COPYRIGHT OWNER OR CONTRIBUTORS 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.
+ */
+
+#ifndef _ARM_ENDIAN_H_
+#define _ARM_ENDIAN_H_
+
+#ifdef __GNUC__
+
+/* NOTE: header <machine/cpu-features.h> could not be included directly
+ * since it defines extra macros, such as PLD.
+ */
+#if defined(__ARM_ARCH_7A__) || defined(__ARM_ARCH_7R__) ||	\
+    defined(__ARM_ARCH_7__) ||					\
+    defined(__ARM_ARCH_6__) || defined(__ARM_ARCH_6J__) || 	\
+    defined(__ARM_ARCH_6K__) || defined(__ARM_ARCH_6Z__) || 	\
+    defined(__ARM_ARCH_6ZK__) || defined(__ARM_ARCH_6T2__)
+
+/* According to RealView Assembler User's Guide, REV and REV16 are available
+ * in Thumb code and 16-bit instructions when used in Thumb-2 code.
+ *
+ * REV Rd, Rm
+ *   Rd and Rm must both be Lo registers.
+ *
+ * REV16 Rd, Rm
+ *   Rd and Rm must both be Lo registers.
+ */
+#ifdef __thumb__
+#define REV_LO_REG	asm("r4")
+#else
+#define REV_LO_REG
+#endif
+
+#define __swap16md(x) ({						\
+	register u_int16_t _x REV_LO_REG = (x);				\
+	__asm volatile ("rev16 %0, %0" : "+r" (_x));			\
+	_x;								\
+})
+
+#define __swap32md(x) ({						\
+	register u_int32_t _x REV_LO_REG = (x);				\
+	__asm volatile ("rev %0, %0" : "+r" (_x));			\
+	_x;								\
+})
+
+#define __swap64md(x) ({						\
+	u_int64_t _x = (x);						\
+	(u_int64_t) __swap32md(_x >> 32) |				\
+	(u_int64_t) __swap32md(_x & 0xffffffff) << 32;			\
+})
+
+/* Tell sys/endian.h we have MD variants of the swap macros.  */
+#define MD_SWAP
+
+#endif	/* __ARM_ARCH__ */
+#endif	/* __GNUC__ */
+
 #ifdef __ARMEB__
 #define _BYTE_ORDER _BIG_ENDIAN
 #else
@@ -8,3 +89,5 @@
 #define	__STRICT_ALIGNMENT
 #include <sys/types.h>
 #include <sys/endian.h>
+
+#endif	/* !_ARM_ENDIAN_H_ */