pull from Blackfin repo: optimized byteswap funcs!

libc/sysdeps/linux/bfin/bits/byteswap.h

@@ -0,0 +1,93 @@
+/* File: libc/sysdeps/linux/bfin/bits/byteswap.h
+ *
+ * Copyright 2004-2006 Analog Devices Inc.
+ *
+ * Enter bugs at http://blackfin.uclinux.org/
+ *
+ * Licensed under the GPL-2 or later.
+ */
+
+#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))
+
+#ifdef __GNUC__
+# define __bswap_16(x) \
+     (__extension__							      \
+      ({ register unsigned short int __v, __x = (x);			      \
+	 if (__builtin_constant_p (__x))				      \
+	   __v = __bswap_constant_16 (__x);				      \
+	 else								      \
+	   __asm__ ("%0 <<= 8;"						      \
+		    "%1.L = %0.L + %0.H (NS);"				      \
+		    : "+d" (__x), "=d" (__v));				      \
+	 __v; }))
+#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))
+
+#ifdef __GNUC__
+# define __bswap_32(x) \
+     (__extension__							      \
+      ({ register unsigned int __v, __x = (x);				      \
+	 if (__builtin_constant_p (__x))				      \
+	   __v = __bswap_constant_32 (__x);				      \
+	 else								      \
+	   __asm__ ("%1 = %0 >> 8 (V);"					      \
+		    "%0 = %0 << 8 (V);"					      \
+		    "%0 = %0 | %1;"					      \
+		    "%1 = PACK(%0.L, %0.H);"				      \
+		    : "+d"(__x), "=&d"(__v));				      \
+	 __v; }))
+#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 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 */