diff --git a/include/lib/libc/endian.h b/include/lib/libc/endian.h
new file mode 100644
index 0000000..4100f57
--- /dev/null
+++ b/include/lib/libc/endian.h
@@ -0,0 +1,191 @@
+/*-
+ * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
+ *
+ * Copyright (c) 2002 Thomas Moestl <tmm@FreeBSD.org>
+ * 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 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 AUTHOR 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.
+ *
+ * $FreeBSD$
+ */
+/*
+ * Portions copyright (c) 2018, ARM Limited and Contributors.
+ * All rights reserved.
+ */
+
+#ifndef ENDIAN_H
+#define ENDIAN_H
+
+#include <cdefs.h>
+#include <stdint.h>
+#include <endian_.h>
+
+/*
+ * General byte order swapping functions.
+ */
+#define	bswap16(x)	__bswap16(x)
+#define	bswap32(x)	__bswap32(x)
+#define	bswap64(x)	__bswap64(x)
+
+/*
+ * Host to big endian, host to little endian, big endian to host, and little
+ * endian to host byte order functions as detailed in byteorder(9).
+ */
+#if _BYTE_ORDER == _LITTLE_ENDIAN
+#define	htobe16(x)	bswap16((x))
+#define	htobe32(x)	bswap32((x))
+#define	htobe64(x)	bswap64((x))
+#define	htole16(x)	((uint16_t)(x))
+#define	htole32(x)	((uint32_t)(x))
+#define	htole64(x)	((uint64_t)(x))
+
+#define	be16toh(x)	bswap16((x))
+#define	be32toh(x)	bswap32((x))
+#define	be64toh(x)	bswap64((x))
+#define	le16toh(x)	((uint16_t)(x))
+#define	le32toh(x)	((uint32_t)(x))
+#define	le64toh(x)	((uint64_t)(x))
+#else /* _BYTE_ORDER != _LITTLE_ENDIAN */
+#define	htobe16(x)	((uint16_t)(x))
+#define	htobe32(x)	((uint32_t)(x))
+#define	htobe64(x)	((uint64_t)(x))
+#define	htole16(x)	bswap16((x))
+#define	htole32(x)	bswap32((x))
+#define	htole64(x)	bswap64((x))
+
+#define	be16toh(x)	((uint16_t)(x))
+#define	be32toh(x)	((uint32_t)(x))
+#define	be64toh(x)	((uint64_t)(x))
+#define	le16toh(x)	bswap16((x))
+#define	le32toh(x)	bswap32((x))
+#define	le64toh(x)	bswap64((x))
+#endif /* _BYTE_ORDER == _LITTLE_ENDIAN */
+
+/* Alignment-agnostic encode/decode bytestream to/from little/big endian. */
+
+static __inline uint16_t
+be16dec(const void *pp)
+{
+	uint8_t const *p = (uint8_t const *)pp;
+
+	return ((p[0] << 8) | p[1]);
+}
+
+static __inline uint32_t
+be32dec(const void *pp)
+{
+	uint8_t const *p = (uint8_t const *)pp;
+
+	return (((unsigned)p[0] << 24) | (p[1] << 16) | (p[2] << 8) | p[3]);
+}
+
+static __inline uint64_t
+be64dec(const void *pp)
+{
+	uint8_t const *p = (uint8_t const *)pp;
+
+	return (((uint64_t)be32dec(p) << 32) | be32dec(p + 4));
+}
+
+static __inline uint16_t
+le16dec(const void *pp)
+{
+	uint8_t const *p = (uint8_t const *)pp;
+
+	return ((p[1] << 8) | p[0]);
+}
+
+static __inline uint32_t
+le32dec(const void *pp)
+{
+	uint8_t const *p = (uint8_t const *)pp;
+
+	return (((unsigned)p[3] << 24) | (p[2] << 16) | (p[1] << 8) | p[0]);
+}
+
+static __inline uint64_t
+le64dec(const void *pp)
+{
+	uint8_t const *p = (uint8_t const *)pp;
+
+	return (((uint64_t)le32dec(p + 4) << 32) | le32dec(p));
+}
+
+static __inline void
+be16enc(void *pp, uint16_t u)
+{
+	uint8_t *p = (uint8_t *)pp;
+
+	p[0] = (u >> 8) & 0xff;
+	p[1] = u & 0xff;
+}
+
+static __inline void
+be32enc(void *pp, uint32_t u)
+{
+	uint8_t *p = (uint8_t *)pp;
+
+	p[0] = (u >> 24) & 0xff;
+	p[1] = (u >> 16) & 0xff;
+	p[2] = (u >> 8) & 0xff;
+	p[3] = u & 0xff;
+}
+
+static __inline void
+be64enc(void *pp, uint64_t u)
+{
+	uint8_t *p = (uint8_t *)pp;
+
+	be32enc(p, (uint32_t)(u >> 32));
+	be32enc(p + 4, (uint32_t)(u & 0xffffffffU));
+}
+
+static __inline void
+le16enc(void *pp, uint16_t u)
+{
+	uint8_t *p = (uint8_t *)pp;
+
+	p[0] = u & 0xff;
+	p[1] = (u >> 8) & 0xff;
+}
+
+static __inline void
+le32enc(void *pp, uint32_t u)
+{
+	uint8_t *p = (uint8_t *)pp;
+
+	p[0] = u & 0xff;
+	p[1] = (u >> 8) & 0xff;
+	p[2] = (u >> 16) & 0xff;
+	p[3] = (u >> 24) & 0xff;
+}
+
+static __inline void
+le64enc(void *pp, uint64_t u)
+{
+	uint8_t *p = (uint8_t *)pp;
+
+	le32enc(p, (uint32_t)(u & 0xffffffffU));
+	le32enc(p + 4, (uint32_t)(u >> 32));
+}
+
+#endif /* ENDIAN_H */