1 files changed, 95 insertions, 0 deletions
diff --git a/libc/sysdeps/linux/i386/bits/byteswap.h b/libc/sysdeps/linux/i386/bits/byteswap.h
new file mode 100644
index 000000000..a1ba6b874
--- /dev/null
+++ b/libc/sysdeps/linux/i386/bits/byteswap.h
@@ -0,0 +1,95 @@
+/* Macros to swap the order of bytes in integer values.
+   Copyright (C) 1997, 1998 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.  */
+
+#if !defined _BYTESWAP_H && !defined _NETINET_IN_H
+# error "Never use <bits/byteswap.h> directly; include <byteswap.h> instead."
+#endif
+
+/* Swap bytes in 16 bit value.  */
+#define __bswap_constant_16(x) \
+     ((((x) >> 8) & 0xff) | (((x) & 0xff) << 8))
+
+#if defined __GNUC__ && __GNUC__ >= 2
+# define __bswap_16(x) \
+     (__extension__							      \
+      ({ register unsigned short int __v;				      \
+	 if (__builtin_constant_p (x))					      \
+	   __v = __bswap_constant_16 (x);				      \
+	 else								      \
+	   __asm__ __volatile__ ("rorw $8, %w0"				      \
+				 : "=r" (__v)				      \
+				 : "0" ((unsigned short int) (x))	      \
+				 : "cc");				      \
+	 __v; }))
+#else
+/* This is better than nothing.  */
+# define __bswap_16(x) __bswap_constant_16 (x)
+#endif
+
+
+/* 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
+/* 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__
+#  define __bswap_32(x) \
+     (__extension__							      \
+      ({ register unsigned int __v;					      \
+	 if (__builtin_constant_p (x))					      \
+	   __v = __bswap_constant_32 (x);				      \
+	 else								      \
+	   __asm__ __volatile__ ("rorw $8, %w0;"			      \
+				 "rorl $16, %0;"			      \
+				 "rorw $8, %w0"				      \
+				 : "=r" (__v)				      \
+				 : "0" ((unsigned int) (x))		      \
+				 : "cc");				      \
+	 __v; }))
+# else
+#  define __bswap_32(x) \
+     (__extension__							      \
+      ({ register unsigned int __v;					      \
+	 if (__builtin_constant_p (x))					      \
+	   __v = __bswap_constant_32 (x);				      \
+	 else								      \
+	   __asm__ __volatile__ ("bswap %0"				      \
+				 : "=r" (__v)				      \
+				 : "0" ((unsigned int) (x)));		      \
+	 __v; }))
+# endif
+#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 { __extension__ unsigned long long int __ll;		      \
+		 unsigned long int __l[2]; } __w, __r;			      \
+	 __w.__ll = (x);						      \
+	 __r.__l[0] = __bswap_32 (__w.__l[1]);				      \
+	 __r.__l[1] = __bswap_32 (__w.__l[0]);				      \
+	 __r.__ll; }))
+#endif