1 /*
   2  * Copyright (c) 1998, 2007, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  *
  23  */
  24 
  25 // For Sun Studio - implementation is in solaris_i486.il.
  26 // For gcc - implementation is just below.
  27 extern "C" u2 _raw_swap_u2(u2 x);
  28 extern "C" u4 _raw_swap_u4(u4 x);
  29 #ifdef AMD64
  30 extern "C" u8 _raw_swap_u8(u8 x);
  31 #else
  32 extern "C" u8 _raw_swap_u8(u4 x, u4 y);
  33 #endif // AMD64
  34 
  35 // Efficient swapping of data bytes from Java byte
  36 // ordering to native byte ordering and vice versa.
  37 inline u2   Bytes::swap_u2(u2 x) {
  38   return _raw_swap_u2(x);
  39 }
  40 
  41 inline u4   Bytes::swap_u4(u4 x) {
  42   return _raw_swap_u4(x);
  43 }
  44 
  45 inline u8   Bytes::swap_u8(u8 x) {
  46 #ifdef AMD64
  47   return _raw_swap_u8(x);
  48 #else
  49   return swap_u8_base(*(u4*)&x, *(((u4*)&x)+1));
  50 #endif // AMD64
  51 
  52 }
  53 
  54 #ifndef AMD64
  55 // Helper function for swap_u8
  56 inline u8   Bytes::swap_u8_base(u4 x, u4 y) {
  57   return _raw_swap_u8(x, y);
  58 }
  59 #endif // !AMD64
  60 
  61 
  62 #ifdef _GNU_SOURCE
  63 
  64 extern "C" {
  65 #ifdef AMD64
  66   inline u2 _raw_swap_u2(u2 x) {
  67     register unsigned short int __dest;
  68     __asm__ ("rorw $8, %w0": "=r" (__dest): "0" (x): "cc");
  69     return __dest;
  70   }
  71   inline u4 _raw_swap_u4(u4 x) {
  72     register unsigned int __dest;
  73     __asm__ ("bswap %0" : "=r" (__dest) : "0" (x));
  74     return __dest;
  75   }
  76   inline u8 _raw_swap_u8(u8 x) {
  77     register unsigned long  __dest;
  78     __asm__ ("bswap %q0" : "=r" (__dest) : "0" (x));
  79     return __dest;
  80   }
  81 #else
  82   inline u2 _raw_swap_u2(u2 x) {
  83     u2 ret;
  84     __asm__ __volatile__ (
  85       "movw %0, %%ax;"
  86       "xchg %%al, %%ah;"
  87       "movw %%ax, %0"
  88       :"=r" (ret)      // output : register 0 => ret
  89       :"0"  (x)        // input  : x => register 0
  90       :"ax", "0"       // clobbered registers
  91     );
  92     return ret;
  93   }
  94 
  95   inline u4 _raw_swap_u4(u4 x) {
  96     u4 ret;
  97     __asm__ __volatile__ (
  98       "bswap %0"
  99       :"=r" (ret)      // output : register 0 => ret
 100       :"0"  (x)        // input  : x => register 0
 101       :"0"             // clobbered register
 102     );
 103     return ret;
 104   }
 105 
 106   inline u8 _raw_swap_u8(u4 x, u4 y) {
 107     return (((u8)_raw_swap_u4(x))<<32) | _raw_swap_u4(y);
 108   }
 109 #endif // AMD64
 110 }
 111 #endif  //_GNU_SOURCE