1 /*
   2  * Copyright (c) 1999, 2019, 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 #ifndef OS_CPU_LINUX_X86_BYTES_LINUX_X86_INLINE_HPP
  26 #define OS_CPU_LINUX_X86_BYTES_LINUX_X86_INLINE_HPP
  27 
  28 #include <byteswap.h>
  29 
  30 // Efficient swapping of data bytes from Java byte
  31 // ordering to native byte ordering and vice versa.
  32 inline u2   Bytes::swap_u2(u2 x) {
  33 #ifdef AMD64
  34   return bswap_16(x);
  35 #else
  36   u2 ret;
  37   __asm__ __volatile__ (
  38     "movw %0, %%ax;"
  39     "xchg %%al, %%ah;"
  40     "movw %%ax, %0"
  41     :"=r" (ret)      // output : register 0 => ret
  42     :"0"  (x)        // input  : x => register 0
  43     :"ax", "0"       // clobbered registers
  44   );
  45   return ret;
  46 #endif // AMD64
  47 }
  48 
  49 inline u4   Bytes::swap_u4(u4 x) {
  50 #ifdef AMD64
  51   return bswap_32(x);
  52 #else
  53   u4 ret;
  54   __asm__ __volatile__ (
  55     "bswap %0"
  56     :"=r" (ret)      // output : register 0 => ret
  57     :"0"  (x)        // input  : x => register 0
  58     :"0"             // clobbered register
  59   );
  60   return ret;
  61 #endif // AMD64
  62 }
  63 
  64 #ifdef AMD64
  65 inline u8 Bytes::swap_u8(u8 x) {
  66   return bswap_64(x);
  67 }
  68 #else
  69 // Helper function for swap_u8
  70 inline u8   Bytes::swap_u8_base(u4 x, u4 y) {
  71   return (((u8)swap_u4(x))<<32) | swap_u4(y);
  72 }
  73 
  74 inline u8 Bytes::swap_u8(u8 x) {
  75   return swap_u8_base(*(u4*)&x, *(((u4*)&x)+1));
  76 }
  77 #endif // !AMD64
  78 
  79 #endif // OS_CPU_LINUX_X86_BYTES_LINUX_X86_INLINE_HPP