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authorMike Frysinger <vapier@gentoo.org>2009-07-20 16:38:30 -0400
committerMike Frysinger <vapier@gentoo.org>2009-07-21 22:26:05 -0400
commit6ca56dd4d711c731d010c484c20384097615f6cd (patch)
tree71ae0f7709dc2841f9ebf10f18e7ee182ee15624 /libc/sysdeps/linux/common/bits/byteswap-common.h
parent4a2724d93bcd8626f2cebead9b263b4f9f86541d (diff)
byteswap: unify common definitions
The majority of the byteswap functions are the same across all arches, so setup a common header to provide definitions if they don't exist. This allows arches to override only the ones they actually want to implement with inline assembly. Signed-off-by: Mike Frysinger <vapier@gentoo.org>
Diffstat (limited to 'libc/sysdeps/linux/common/bits/byteswap-common.h')
-rw-r--r--libc/sysdeps/linux/common/bits/byteswap-common.h108
1 files changed, 108 insertions, 0 deletions
diff --git a/libc/sysdeps/linux/common/bits/byteswap-common.h b/libc/sysdeps/linux/common/bits/byteswap-common.h
new file mode 100644
index 000000000..8586ed008
--- /dev/null
+++ b/libc/sysdeps/linux/common/bits/byteswap-common.h
@@ -0,0 +1,108 @@
+/* Macros to swap the order of bytes in integer values.
+ Copyright (C) 1997,1998,2000,2001,2002,2005 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 Lesser General Public
+ License as published by the Free Software Foundation; either
+ version 2.1 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
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public
+ License along with the GNU C Library; if not, write to the Free
+ Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
+ 02111-1307 USA. */
+
+#if !defined _BYTESWAP_H && !defined _NETINET_IN_H
+# error "Never use <bits/byteswap.h> directly; include <byteswap.h> instead."
+#endif
+
+#ifndef _BITS_BYTESWAP_H
+#define _BITS_BYTESWAP_H 1
+
+/* Swap bytes in 16 bit value. */
+#define __bswap_constant_16(x) \
+ ((((x) >> 8) & 0xffu) | (((x) & 0xffu) << 8))
+
+#ifndef __bswap_non_constant_16
+# define __bswap_non_constant_16(x) __bswap_constant_16(x)
+#endif
+#ifdef __GNUC__
+# define __bswap_16(x) \
+ (__extension__ \
+ ({ unsigned short int __bsv, __bsx = (x); \
+ if (__builtin_constant_p (__bsx)) \
+ __bsv = __bswap_constant_16 (__bsx); \
+ else \
+ __bsv = __bswap_non_constant_16 (__bsx); \
+ __bsv; }))
+#else
+static __inline unsigned short int
+__bswap_16 (unsigned short int __bsx)
+{
+ return __bswap_constant_16 (__bsx);
+}
+#endif
+
+/* Swap bytes in 32 bit value. */
+#define __bswap_constant_32(x) \
+ ((((x) & 0xff000000u) >> 24) | (((x) & 0x00ff0000u) >> 8) | \
+ (((x) & 0x0000ff00u) << 8) | (((x) & 0x000000ffu) << 24))
+
+#ifndef __bswap_non_constant_32
+# define __bswap_non_constant_32(x) __bswap_constant_32(x)
+#endif
+#ifdef __GNUC__
+# define __bswap_32(x) \
+ (__extension__ \
+ ({ unsigned int __bsv, __bsx = (x); \
+ if (__builtin_constant_p (__bsx)) \
+ __bsv = __bswap_constant_32 (__bsx); \
+ else \
+ __bsv = __bswap_non_constant_32 (__bsx); \
+ __bsv; }))
+#else
+static __inline unsigned int
+__bswap_32 (unsigned int __bsx)
+{
+ return __bswap_constant_32 (__bsx);
+}
+#endif
+
+#if defined __GNUC__ && __GNUC__ >= 2
+/* Swap bytes in 64 bit value. */
+# define __bswap_constant_64(x) \
+ ((((x) & 0xff00000000000000ull) >> 56) \
+ | (((x) & 0x00ff000000000000ull) >> 40) \
+ | (((x) & 0x0000ff0000000000ull) >> 24) \
+ | (((x) & 0x000000ff00000000ull) >> 8) \
+ | (((x) & 0x00000000ff000000ull) << 8) \
+ | (((x) & 0x0000000000ff0000ull) << 24) \
+ | (((x) & 0x000000000000ff00ull) << 40) \
+ | (((x) & 0x00000000000000ffull) << 56))
+
+# ifndef __bswap_non_constant_64
+# define __bswap_non_constant_64(x) \
+ (__extension__ \
+ ({ union { __extension__ unsigned long long int __ll; \
+ unsigned int __l[2]; } __w, __r; \
+ __w.__ll = (x); \
+ __r.__l[0] = __bswap_non_constant_32 (__w.__l[1]); \
+ __r.__l[1] = __bswap_non_constant_32 (__w.__l[0]); \
+ __r.__ll; }))
+# endif
+# define __bswap_64(x) \
+ (__extension__ \
+ ({ __extension__ unsigned long long int __ll; \
+ if (__builtin_constant_p (x)) \
+ __ll = __bswap_constant_64 (x); \
+ else \
+ __ll = __bswap_non_constant_64 (x); \
+ __ll; }))
+#endif
+
+#endif /* _BITS_BYTESWAP_H */