diff --git a/sys/arch/arm/include/Makefile b/sys/arch/arm/include/Makefile
index 126d270ca442..13b00e57ea00 100644
--- a/sys/arch/arm/include/Makefile
+++ b/sys/arch/arm/include/Makefile
@@ -1,10 +1,10 @@
-#	$NetBSD: Makefile,v 1.25 2002/08/07 05:14:58 briggs Exp $
+#	$NetBSD: Makefile,v 1.26 2002/08/13 22:41:36 thorpej Exp $
 
 KDIR=	/sys/arch/arm/include
 INCSDIR= /usr/include/arm
 
 INCS=	ansi.h aout_machdep.h armreg.h asm.h \
-	bswap.h bus.h \
+	bswap.h byte_swap.h bus.h \
 	cdefs.h cpu.h \
 	db_machdep.h disklabel.h \
 	elf_machdep.h endian.h endian_machdep.h \
diff --git a/sys/arch/arm/include/bswap.h b/sys/arch/arm/include/bswap.h
index 17bc01e8be7b..b181651fa831 100644
--- a/sys/arch/arm/include/bswap.h
+++ b/sys/arch/arm/include/bswap.h
@@ -1,4 +1,4 @@
-/*      $NetBSD: bswap.h,v 1.1 2001/01/10 19:02:05 bjh21 Exp $      */
+/*      $NetBSD: bswap.h,v 1.2 2002/08/13 22:41:36 thorpej Exp $      */
 
 #ifndef _MACHINE_BSWAP_H_
 #define	_MACHINE_BSWAP_H_
@@ -6,4 +6,12 @@
 #define __BSWAP_RENAME
 #include <sys/bswap.h>
 
+#ifdef __GNUC__
+
+#include <arm/byte_swap.h>
+#define	bswap16(x)	__byte_swap_word(x)
+#define	bswap32(x)	__byte_swap_long(x)
+
+#endif /* __GNUC__ */
+
 #endif /* !_MACHINE_BSWAP_H_ */
diff --git a/sys/arch/arm/include/byte_swap.h b/sys/arch/arm/include/byte_swap.h
new file mode 100644
index 000000000000..92c422294eda
--- /dev/null
+++ b/sys/arch/arm/include/byte_swap.h
@@ -0,0 +1,101 @@
+/*	$NetBSD: byte_swap.h,v 1.1 2002/08/13 22:41:36 thorpej Exp $	*/
+
+/*-
+ * Copyright (c) 1997, 1999, 2002 The NetBSD Foundation, Inc.
+ * All rights reserved.
+ *
+ * This code is derived from software contributed to The NetBSD Foundation
+ * by Charles M. Hannum, Neil A. Carson, and Jason R. Thorpe.
+ *
+ * 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.
+ * 3. All advertising materials mentioning features or use of this software
+ *    must display the following acknowledgement:
+ *	This product includes software developed by the NetBSD
+ *	Foundation, Inc. and its contributors.
+ * 4. Neither the name of The NetBSD Foundation nor the names of its
+ *    contributors may be used to endorse or promote products derived
+ *    from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. 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 FOUNDATION 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_BYTE_SWAP_H_
+#define	_ARM_BYTE_SWAP_H_
+
+#include <sys/types.h>
+
+static __inline u_int32_t
+__byte_swap_long_variable(u_int32_t v)
+{
+	int tmp;
+
+	__asm __volatile(
+		"eor	%1, %2, %2, ror #16\n"
+		"bic	%1, %1, #0x00ff0000\n"
+		"mov	%0, %2, ror #8\n"
+		"eor	%0, %0, %1, lsr #8"
+	: "=r" (v), "=&r" (tmp)
+	: "0" (v));
+
+	return (v);
+}
+
+static __inline u_int16_t
+__byte_swap_word_variable(u_int16_t v)
+{
+
+	__asm __volatile(
+		"mov	%0, %1, ror #8\n"
+		"orr	%0, %0, %0, lsr #16\n"
+		"bic	%0, %0, %0, lsl #16"
+	: "=r" (v)
+	: "0" (v));
+
+	return (v);
+}
+
+#ifdef __OPTIMIZE__
+
+#define __byte_swap_long_constant(x)	\
+	((((x) & 0xff000000) >> 24) |	\
+	 (((x) & 0x00ff0000) >>  8) |	\
+	 (((x) & 0x0000ff00) <<  8) |	\
+	 (((x) & 0x000000ff) << 24))
+
+#define	__byte_swap_word_constant(x)	\
+	((((x) & 0xff00) >> 8) |	\
+	 (((x) & 0x00ff) << 8))
+
+#define	__byte_swap_long(x)		\
+	(__builtin_constant_p((x)) ?	\
+	 __byte_swap_long_constant(x) :	__byte_swap_long_variable(x))
+
+#define	__byte_swap_word(x)		\
+	(__builtin_constant_p((x)) ?	\
+	 __byte_swap_word_constant(x) : __byte_swap_word_variable(x))
+
+#else
+
+#define	__byte_swap_long(x)	__byte_swap_long_variable(x)
+#define	__byte_swap_word(x)	__byte_swap_word_variable(x)
+
+#endif /* __OPTIMIZE__ */
+
+#endif /* _ARM_BYTE_SWAP_H_ */
diff --git a/sys/arch/arm/include/endian_machdep.h b/sys/arch/arm/include/endian_machdep.h
index aed1467b47d4..6b8ef466ab72 100644
--- a/sys/arch/arm/include/endian_machdep.h
+++ b/sys/arch/arm/include/endian_machdep.h
@@ -1,4 +1,4 @@
-/* $NetBSD: endian_machdep.h,v 1.3 2001/02/17 14:55:44 bjh21 Exp $ */
+/* $NetBSD: endian_machdep.h,v 1.4 2002/08/13 22:41:36 thorpej Exp $ */
 
 /* GCC predefines __ARMEB__ when building for big-endian ARM. */
 #ifdef __ARMEB__
@@ -6,3 +6,16 @@
 #else
 #define _BYTE_ORDER _LITTLE_ENDIAN
 #endif
+
+#ifdef __GNUC__
+
+#include <arm/byte_swap.h>
+
+#if _BYTE_ORDER == _LITTLE_ENDIAN
+#define	ntohl(x)	((in_addr_t)__byte_swap_long((in_addr_t)(x)))
+#define	ntohs(x)	((in_port_t)__byte_swap_word((in_port_t)(x)))
+#define	htonl(x)	((in_addr_t)__byte_swap_long((in_addr_t)(x)))
+#define	htons(x)	((in_port_t)__byte_swap_word((in_port_t)(x)))
+#endif
+
+#endif