Use hardware support for byteswapping on glibc x86 etc.

On Fedora 19 x86-64, the new bswap_64 needs 1 instruction,
whereas the old swap64 needed 30.
* admin/merge-gnulib (GNULIB_MODULES): Add byteswap.
* lib/byteswap.in.h, m4/byteswap.m4: New files, copied from Gnulib.
* lib/gnulib.mk, m4/gnulib-comp.m4: Regenerate.
* src/fringe.c (init_fringe_bitmap) [WORDS_BIGENDIAN]:
* src/sound.c (le2hl, le2hs, be2hl) [!WINDOWSNT]:
Use byteswap.h's macros to swap bytes.
* src/lisp.h (swap16, swap32, swap64): Remove.
All uses replaced by bswap_16, bswap_32, bswap_64.

6 files changed, 27 insertions, 55 deletions

diff --git a/src/ChangeLog b/src/ChangeLog
index 4fae03d6965..38fb35ddf54 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,5 +1,14 @@
 2013-10-04  Paul Eggert  <eggert@cs.ucla.edu>
 
+        Use hardware support for byteswapping on glibc x86 etc.
+        On Fedora 19 x86-64, the new bswap_64 needs 1 instruction,
+        whereas the old swap64 needed 30.
+        * fringe.c (init_fringe_bitmap) [WORDS_BIGENDIAN]:
+        * sound.c (le2hl, le2hs, be2hl) [!WINDOWSNT]:
+        Use byteswap.h's macros to swap bytes.
+        * lisp.h (swap16, swap32, swap64): Remove.
+        All uses replaced by bswap_16, bswap_32, bswap_64.
+
         * bytecode.c (exec_byte_code): Use some more volatile variables
         to work around local variables getting clobbered by longjmp.
         Port to pre-C99, which doesn't allow decls after stmts.
diff --git a/src/data.c b/src/data.c
index b268616fd26..a6bfe50a3bb 100644
--- a/src/data.c
+++ b/src/data.c
@@ -21,6 +21,7 @@ along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.  */
 #include <config.h>
 #include <stdio.h>
 
+#include <byteswap.h>
 #include <intprops.h>
 
 #include "lisp.h"
@@ -3185,9 +3186,9 @@ size_t_to_host_endian (size_t val)
 {
 #ifdef WORDS_BIGENDIAN
 # if BITS_PER_SIZE_T == 64
-  return swap64 (val);
+  return bswap_64 (val);
 # else
-  return swap32 (val);
+  return bswap_32 (val);
 # endif
 #else
   return val;
diff --git a/src/fringe.c b/src/fringe.c
index 85103f7f08d..3537027f1dd 100644
--- a/src/fringe.c
+++ b/src/fringe.c
@@ -20,6 +20,8 @@ along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.  */
 #include <config.h>
 #include <stdio.h>
 
+#include <byteswap.h>
+
 #include "lisp.h"
 #include "frame.h"
 #include "window.h"
@@ -1519,7 +1521,7 @@ init_fringe_bitmap (int which, struct fringe_bitmap *fb, int once_p)
                                    | (swap_nibble[(b>>12) & 0xf]));
               b >>= (16 - fb->width);
 #ifdef WORDS_BIGENDIAN
-              b = ((b >> 8) | (b << 8));
+              b = bswap_16 (b);
 #endif
               *bits++ = b;
             }
diff --git a/src/lisp.h b/src/lisp.h
index f949978ceed..2f0279ef542 100644
--- a/src/lisp.h
+++ b/src/lisp.h
@@ -4366,30 +4366,6 @@ functionp (Lisp_Object object)
     return 0;
 }
 
-INLINE uint16_t
-swap16 (uint16_t val)
-{
-    return (val << 8) | (val & 0xFF);
-}
-
-INLINE uint32_t
-swap32 (uint32_t val)
-{
-  uint32_t low = swap16 (val & 0xFFFF);
-  uint32_t high = swap16 (val >> 16);
-  return (low << 16) | high;
-}
-
-#ifdef UINT64_MAX
-INLINE uint64_t
-swap64 (uint64_t val)
-{
-  uint64_t low = swap32 (val & 0xFFFFFFFF);
-  uint64_t high = swap32 (val >> 32);
-  return (low << 32) | high;
-}
-#endif
-
 #if ((SIZE_MAX >> 31) >> 1) & 1
 # define BITS_PER_SIZE_T 64
 #else
diff --git a/src/sound.c b/src/sound.c
index 27e06b8abab..f8c6b483056 100644
--- a/src/sound.c
+++ b/src/sound.c
@@ -55,6 +55,8 @@ along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.  */
 /* BEGIN: Non Windows Includes */
 #ifndef WINDOWSNT
 
+#include <byteswap.h>
+
 #include <sys/ioctl.h>
 
 /* FreeBSD has machine/soundcard.h.  Voxware sound driver docs mention
@@ -461,8 +463,7 @@ static u_int32_t
 le2hl (u_int32_t value)
 {
 #ifdef WORDS_BIGENDIAN
-  unsigned char *p = (unsigned char *) &value;
-  value = p[0] + (p[1] << 8) + (p[2] << 16) + (p[3] << 24);
+  value = bswap_32 (value);
 #endif
   return value;
 }
@@ -475,8 +476,7 @@ static u_int16_t
 le2hs (u_int16_t value)
 {
 #ifdef WORDS_BIGENDIAN
-  unsigned char *p = (unsigned char *) &value;
-  value = p[0] + (p[1] << 8);
+  value = bswap_16 (value);
 #endif
   return value;
 }
@@ -489,30 +489,11 @@ static u_int32_t
 be2hl (u_int32_t value)
 {
 #ifndef WORDS_BIGENDIAN
-  unsigned char *p = (unsigned char *) &value;
-  value = p[3] + (p[2] << 8) + (p[1] << 16) + (p[0] << 24);
+  value = bswap_32 (value);
 #endif
   return value;
 }
 
-
-#if 0 /* Currently not used.  */
-
-/* Convert 16-bit value VALUE which is in big-endian byte-order
-   to host byte-order.  */
-
-static u_int16_t
-be2hs (u_int16_t value)
-{
-#ifndef WORDS_BIGENDIAN
-  unsigned char *p = (unsigned char *) &value;
-  value = p[1] + (p[0] << 8);
-#endif
-  return value;
-}
-
-#endif /* 0 */
-
 /***********************************************************************
                           RIFF-WAVE (*.wav)
  ***********************************************************************/
diff --git a/src/xsettings.c b/src/xsettings.c
index 8fe82fec74b..e5a66c4cf0a 100644
--- a/src/xsettings.c
+++ b/src/xsettings.c
@@ -22,6 +22,9 @@ along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.  */
 #include <float.h>
 #include <limits.h>
 #include <fcntl.h>
+
+#include <byteswap.h>
+
 #include "lisp.h"
 #include "xterm.h"
 #include "xsettings.h"
@@ -405,7 +408,7 @@ parse_settings (unsigned char *prop,
 
   if (bytes < 12) return BadLength;
   memcpy (&n_settings, prop+8, 4);
-  if (my_bo != that_bo) n_settings = swap32 (n_settings);
+  if (my_bo != that_bo) n_settings = bswap_32 (n_settings);
   bytes_parsed = 12;
 
   memset (settings, 0, sizeof (*settings));
@@ -427,7 +430,7 @@ parse_settings (unsigned char *prop,
 
       memcpy (&nlen, prop+bytes_parsed, 2);
       bytes_parsed += 2;
-      if (my_bo != that_bo) nlen = swap16 (nlen);
+      if (my_bo != that_bo) nlen = bswap_16 (nlen);
       if (bytes_parsed+nlen > bytes) return BadLength;
       to_cpy = nlen > 127 ? 127 : nlen;
       memcpy (name, prop+bytes_parsed, to_cpy);
@@ -454,7 +457,7 @@ parse_settings (unsigned char *prop,
           if (want_this)
             {
               memcpy (&ival, prop+bytes_parsed, 4);
-              if (my_bo != that_bo) ival = swap32 (ival);
+              if (my_bo != that_bo) ival = bswap_32 (ival);
             }
           bytes_parsed += 4;
           break;
@@ -463,7 +466,7 @@ parse_settings (unsigned char *prop,
           if (bytes_parsed+4 > bytes) return BadLength;
           memcpy (&vlen, prop+bytes_parsed, 4);
           bytes_parsed += 4;
-          if (my_bo != that_bo) vlen = swap32 (vlen);
+          if (my_bo != that_bo) vlen = bswap_32 (vlen);
           if (want_this)
             {
               to_cpy = vlen > 127 ? 127 : vlen;