M68k optimized functions for swapping byte order.

sysdeps/m68k/bits/byteswap.h

@@ -0,0 +1,63 @@
+/* Macros to swap the order of bytes in integer values.  m68k version.
+   Copyright (C) 1997 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Library General Public License as
+   published by the Free Software Foundation; either version 2 of the
+   License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Library General Public License for more details.
+
+   You should have received a copy of the GNU Library General Public
+   License along with the GNU C Library; see the file COPYING.LIB.  If not,
+   write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+   Boston, MA 02111-1307, USA.  */
+
+#ifndef _BITS_BYTESWAP_H
+#define _BITS_BYTESWAP_H	1
+
+/* Swap bytes in 16 bit value.  We don't provide an assembler version
+   because GCC is smart enough to generate optimal assembler output, and
+   this allows for better cse.  */
+#define __bswap_16(x) \
+  ((((x) >> 8) & 0xff) | (((x) & 0xff) << 8))
+
+/* Swap bytes in 32 bit value.  */
+#define __bswap_constant_32(x) \
+  ((((x) & 0xff000000) >> 24) | (((x) & 0x00ff0000) >>  8) | \
+   (((x) & 0x0000ff00) <<  8) | (((x) & 0x000000ff) << 24))
+
+#if defined __GNUC__ && __GNUC__ >= 2
+#define __bswap_32(x) \
+  __extension__					\
+  ({ unsigned int __v;				\
+     if (__builtin_constant_p (x))		\
+       __v = __bswap_constant_32 (x);		\
+     else					\
+       __asm__ __volatile__ ("ror%.w %#8, %0;"	\
+			     "swap %0;"		\
+			     "ror%.w %#8, %0"	\
+			     : "=d" (__v)	\
+			     : "0" (x));	\
+     __v; })
+#else
+#define __bswap_32(x) __bswap_constant_32 (x)
+#endif
+
+#if defined __GNUC__ && __GNUC__ >= 2
+/* Swap bytes in 64 bit value.  */
+#define __bswap_64(x) \
+  __extension__						\
+  ({ union { unsigned long long int __ll;		\
+	     unsigned long int __l[2]; } __v, __r;	\
+     __v.__ll = (x);					\
+     __r.__l[0] = __bswap_32 (__v.__l[1]);		\
+     __r.__l[1] = __bswap_32 (__v.__l[0]);		\
+     __r.__ll; })
+#endif
+
+#endif /* bits/byteswap.h */