1 /*
   2  * Copyright (c) 1998, 2010, 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_WINDOWS_X86_VM_BYTES_WINDOWS_X86_INLINE_HPP
  26 #define OS_CPU_WINDOWS_X86_VM_BYTES_WINDOWS_X86_INLINE_HPP
  27 
  28 #pragma warning(disable: 4035) // Disable warning 4035: no return value
  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   address p = (address) &x;
  35   return  ( (u2(p[0]) << 8 ) | ( u2(p[1])) );
  36 #else
  37   __asm {
  38     mov ax, x
  39     xchg al, ah
  40   }
  41   // no return statement needed, result is already in ax
  42   // compiler warning C4035 disabled via warning pragma
  43 #endif // AMD64
  44 }
  45 
  46 inline u4 Bytes::swap_u4(u4 x) {
  47 #ifdef AMD64
  48   address p = (address) &x;
  49   return ( (u4(p[0]) << 24) | (u4(p[1]) << 16) | (u4(p[2]) << 8) | u4(p[3])) ;
  50 #else
  51   __asm {
  52     mov eax, x
  53     bswap eax
  54   }
  55   // no return statement needed, result is already in eax
  56   // compiler warning C4035 disabled via warning pragma
  57 #endif // AMD64
  58 }
  59 
  60 #ifdef AMD64
  61 inline u8 Bytes::swap_u8(u8 x) {
  62   address p = (address) &x;
  63   return ( (u8(p[0]) << 56) | (u8(p[1]) << 48) | (u8(p[2]) << 40) | (u8(p[3]) << 32) |
  64            (u8(p[4]) << 24) | (u8(p[5]) << 16) | (u8(p[6]) << 8)  | u8(p[7])) ;
  65 }
  66 
  67 #else
  68 // Helper function for swap_u8
  69 inline u8 Bytes::swap_u8_base(u4 x, u4 y) {
  70   __asm {
  71     mov eax, y
  72     mov edx, x
  73     bswap eax
  74     bswap edx
  75   }
  76   // no return statement needed, result is already in edx:eax
  77   // compiler warning C4035 disabled via warning pragma
  78 }
  79 
  80 inline u8 Bytes::swap_u8(u8 x) {
  81   return swap_u8_base(*(u4*)&x, *(((u4*)&x)+1));
  82 }
  83 #endif // AMD64
  84 
  85 #pragma warning(default: 4035) // Enable warning 4035: no return value
  86 
  87 #endif // OS_CPU_WINDOWS_X86_VM_BYTES_WINDOWS_X86_INLINE_HPP