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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/i386
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/i386')
-rw-r--r--libc/sysdeps/linux/i386/bits/byteswap.h121
1 files changed, 22 insertions, 99 deletions
diff --git a/libc/sysdeps/linux/i386/bits/byteswap.h b/libc/sysdeps/linux/i386/bits/byteswap.h
index 32b21920d..052eda381 100644
--- a/libc/sysdeps/linux/i386/bits/byteswap.h
+++ b/libc/sysdeps/linux/i386/bits/byteswap.h
@@ -17,117 +17,40 @@
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
+#ifndef _ASM_BITS_BYTESWAP_H
+#define _ASM_BITS_BYTESWAP_H 1
-/* Swap bytes in 16 bit value. */
-#define __bswap_constant_16(x) \
- ((((x) >> 8) & 0xff) | (((x) & 0xff) << 8))
-
-#ifdef __GNUC__
-# if __GNUC__ >= 2
-# define __bswap_16(x) \
+#define __bswap_non_constant_16(x) \
(__extension__ \
- ({ register unsigned short int __v, __x = (x); \
- if (__builtin_constant_p (__x)) \
- __v = __bswap_constant_16 (__x); \
- else \
- __asm__ ("rorw $8, %w0" \
- : "=r" (__v) \
- : "0" (__x) \
- : "cc"); \
+ ({ register unsigned short int __v; \
+ __asm__ ("rorw $8, %w0" \
+ : "=r" (__v) \
+ : "0" (x) \
+ : "cc"); \
__v; }))
-# else
-/* This is better than nothing. */
-# define __bswap_16(x) \
- (__extension__ \
- ({ register unsigned short int __x = (x); __bswap_constant_16 (__x); }))
-# endif
-#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) & 0xff000000) >> 24) | (((x) & 0x00ff0000) >> 8) | \
- (((x) & 0x0000ff00) << 8) | (((x) & 0x000000ff) << 24))
-#ifdef __GNUC__
-# if __GNUC__ >= 2
/* To swap the bytes in a word the i486 processors and up provide the
`bswap' opcode. On i386 we have to use three instructions. */
-# if !defined __i486__ && !defined __pentium__ && !defined __pentiumpro__ \
+#if !defined __i486__ && !defined __pentium__ && !defined __pentiumpro__ \
&& !defined __pentium4__
-# define __bswap_32(x) \
+# define __bswap_non_constant_32(x) \
(__extension__ \
- ({ register unsigned int __v, __x = (x); \
- if (__builtin_constant_p (__x)) \
- __v = __bswap_constant_32 (__x); \
- else \
- __asm__ ("rorw $8, %w0;" \
- "rorl $16, %0;" \
- "rorw $8, %w0" \
- : "=r" (__v) \
- : "0" (__x) \
- : "cc"); \
+ ({ register unsigned int __v; \
+ __asm__ ("rorw $8, %w0;" \
+ "rorl $16, %0;" \
+ "rorw $8, %w0" \
+ : "=r" (__v) \
+ : "0" (x) \
+ : "cc"); \
__v; }))
-# else
-# define __bswap_32(x) \
+#else
+# define __bswap_non_constant_32(x) \
(__extension__ \
- ({ register unsigned int __v, __x = (x); \
- if (__builtin_constant_p (__x)) \
- __v = __bswap_constant_32 (__x); \
- else \
- __asm__ ("bswap %0" : "=r" (__v) : "0" (__x)); \
+ ({ register unsigned int __v; \
+ __asm__ ("bswap %0" : "=r" (__v) : "0" (x)); \
__v; }))
-# endif
-# else
-# define __bswap_32(x) \
- (__extension__ \
- ({ register unsigned int __x = (x); __bswap_constant_32 (__x); }))
-# endif
-#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))
-
-# define __bswap_64(x) \
- (__extension__ \
- ({ union { __extension__ unsigned long long int __ll; \
- unsigned long int __l[2]; } __w, __r; \
- if (__builtin_constant_p (x)) \
- __r.__ll = __bswap_constant_64 (x); \
- else \
- { \
- __w.__ll = (x); \
- __r.__l[0] = __bswap_32 (__w.__l[1]); \
- __r.__l[1] = __bswap_32 (__w.__l[0]); \
- } \
- __r.__ll; }))
#endif
-#endif /* _BITS_BYTESWAP_H */
+#include <bits/byteswap-common.h>