From 1bc80b1c64ec5122d5a34b5207a5d65625e7e54d Mon Sep 17 00:00:00 2001
From: dlg <dlg@openbsd.org>
Date: Sun, 11 Jan 2015 11:18:36 +0000
Subject: [PATCH] armv6 introduced opcodes for reversing words in registers. we
 can use these on armv7 as a backend for byteswapping things that endian.h
 provide.

i dunno if its faster, but it makes smaller code. saves 30k on
GENERIC-OMAP.

ok jsing@ bmercer@ jsg@
---
 sys/arch/arm/include/endian.h | 47 ++++++++++++++++++++++++++++++++++-
 1 file changed, 46 insertions(+), 1 deletion(-)

diff --git a/sys/arch/arm/include/endian.h b/sys/arch/arm/include/endian.h
index 0c12941585a..e142ad5c3ee 100644
--- a/sys/arch/arm/include/endian.h
+++ b/sys/arch/arm/include/endian.h
@@ -1,8 +1,53 @@
-/*	$OpenBSD: endian.h,v 1.7 2014/07/12 16:25:08 guenther Exp $	*/
+/*	$OpenBSD: endian.h,v 1.8 2015/01/11 11:18:36 dlg Exp $	*/
 
 #ifndef _ARM_ENDIAN_H_
 #define _ARM_ENDIAN_H_
 
+#ifdef _KERNEL
+#ifdef __armv7__
+#ifdef __GNUC__
+
+static inline __uint16_t
+___swap16md(__uint16_t x)
+{
+	__uint16_t rv;
+
+	__asm ("rev16 %0, %1" : "=r" (rv) : "r" (x));
+
+	return (rv);
+}
+#define __swap16md(x) ___swap16md(x)
+
+static inline __uint32_t
+___swap32md(__uint32_t x)
+{
+	__uint32_t rv;
+
+	__asm ("rev %0, %1" : "=r" (rv) : "r" (x));
+
+	return (rv);
+}
+#define __swap32md(x) ___swap32md(x)
+
+static inline __uint64_t
+___swap64md(__uint64_t x)
+{
+	__uint64_t rv;
+
+	rv = (__uint64_t)__swap32md(x >> 32) |
+	    (__uint64_t)__swap32md(x) << 32;
+
+	return (rv);
+}
+#define __swap64md(x) ___swap64md(x)
+
+/* Tell sys/endian.h we have MD variants of the swap macros.  */
+#define __HAVE_MD_SWAP
+
+#endif  /* __GNUC__ */
+#endif  /* __armv7__ */
+#endif  /* _KERNEL */
+
 #define _BYTE_ORDER _LITTLE_ENDIAN
 #define	__STRICT_ALIGNMENT
 
-- 
2.20.1