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[PATCH v2 9/10] Tilera (and Linux asm-generic) support for glibc
- From: Chris Metcalf <cmetcalf at tilera dot com>
- To: libc-alpha at sourceware dot org
- Cc: Arnd Bergmann <arnd at arndb dot de>, Linas Vepstas <linas at codeaurora dot org>, Guan Xuetao <gxt at mprc dot pku dot edu dot cn>, Jonas Bonn <jonas at southpole dot se>, Chen Liqin <liqin dot chen at gmail dot com>
- Date: Wed, 9 Nov 2011 19:56:20 -0500
- Subject: [PATCH v2 9/10] Tilera (and Linux asm-generic) support for glibc
- References: <201111100054.pAA0sf6u025585@farm-0002.internal.tilera.com>
(New change since v1 of patch.)
2011-11-09 Chris Metcalf <cmetcalf@tilera.com>
* bits/byteswap.h (__bswap*): Use __builtin_bswap for gcc 4.3 and
above. Improves code generation for gcc 4.3 and 4.4 compilers
without bswap pattern detection.
diff --git a/bits/byteswap.h b/bits/byteswap.h
index 45cb947..89036bc 100644
--- a/bits/byteswap.h
+++ b/bits/byteswap.h
@@ -24,42 +24,53 @@
#ifndef _BITS_BYTESWAP_H
#define _BITS_BYTESWAP_H 1
+#include <features.h>
+
+#if __GNUC_PREREQ (4,3)
+# define __bswap_16(x) ((unsigned short int) (__builtin_bswap32 (x) >> 16))
+# define __bswap_32(x) ((unsigned int) __builtin_bswap32 (x))
+# define __bswap_64(x) ((unsigned long long int) __builtin_bswap64 (x))
+# define __bswap_constant_16(x) __bswap_16 (x)
+# define __bswap_constant_32(x) __bswap_32 (x)
+# define __bswap_constant_64(x) __bswap_64 (x)
+#else
+
/* Swap bytes in 16 bit value. */
-#define __bswap_constant_16(x) \
+# define __bswap_constant_16(x) \
((((x) >> 8) & 0xffu) | (((x) & 0xffu) << 8))
-#ifdef __GNUC__
-# define __bswap_16(x) \
+# ifdef __GNUC__
+# define __bswap_16(x) \
(__extension__ \
({ unsigned short int __bsx = (x); __bswap_constant_16 (__bsx); }))
-#else
+# else
static __inline unsigned short int
__bswap_16 (unsigned short int __bsx)
{
return __bswap_constant_16 (__bsx);
}
-#endif
+# endif
/* Swap bytes in 32 bit value. */
-#define __bswap_constant_32(x) \
+# define __bswap_constant_32(x) \
((((x) & 0xff000000u) >> 24) | (((x) & 0x00ff0000u) >> 8) | \
(((x) & 0x0000ff00u) << 8) | (((x) & 0x000000ffu) << 24))
-#ifdef __GNUC__
-# define __bswap_32(x) \
+# ifdef __GNUC__
+# define __bswap_32(x) \
(__extension__ \
({ register unsigned int __bsx = (x); __bswap_constant_32 (__bsx); }))
-#else
+# else
static __inline unsigned int
__bswap_32 (unsigned int __bsx)
{
return __bswap_constant_32 (__bsx);
}
-#endif
+# endif
-#if defined __GNUC__ && __GNUC__ >= 2
+# if defined __GNUC__ && __GNUC__ >= 2
/* Swap bytes in 64 bit value. */
-# define __bswap_constant_64(x) \
+# define __bswap_constant_64(x) \
((((x) & 0xff00000000000000ull) >> 56) \
| (((x) & 0x00ff000000000000ull) >> 40) \
| (((x) & 0x0000ff0000000000ull) >> 24) \
@@ -69,7 +80,7 @@ __bswap_32 (unsigned int __bsx)
| (((x) & 0x000000000000ff00ull) << 40) \
| (((x) & 0x00000000000000ffull) << 56))
-# define __bswap_64(x) \
+# define __bswap_64(x) \
(__extension__ \
({ union { __extension__ unsigned long long int __ll; \
unsigned int __l[2]; } __w, __r; \
@@ -82,6 +93,8 @@ __bswap_32 (unsigned int __bsx)
__r.__l[1] = __bswap_32 (__w.__l[0]); \
} \
__r.__ll; }))
+# endif
+
#endif
#endif /* _BITS_BYTESWAP_H */