libkern/libkern/i386/OSByteOrder.h

   1 /*
   2  * Copyright (c) 1999-2005 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
   5  *
   6  * This file contains Original Code and/or Modifications of Original Code
   7  * as defined in and that are subject to the Apple Public Source License
   8  * Version 2.0 (the 'License'). You may not use this file except in
   9  * compliance with the License. The rights granted to you under the License
  10  * may not be used to create, or enable the creation or redistribution of,
  11  * unlawful or unlicensed copies of an Apple operating system, or to
  12  * circumvent, violate, or enable the circumvention or violation of, any
  13  * terms of an Apple operating system software license agreement.
  14  *
  15  * Please obtain a copy of the License at
  16  * http://www.opensource.apple.com/apsl/ and read it before using this file.
  17  *
  18  * The Original Code and all software distributed under the License are
  19  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  20  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  21  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  22  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  23  * Please see the License for the specific language governing rights and
  24  * limitations under the License.
  25  *
  26  * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
  27  */
  28
  29 #ifndef _OS_OSBYTEORDERI386_H
  30 #define _OS_OSBYTEORDERI386_H
  31
  32 #include <stdint.h>
  33
  34 #if !defined(OS_INLINE)
  35 # if defined(__STDC_VERSION__) && __STDC_VERSION__ >= 199901L
  36 #        define OS_INLINE static inline
  37 # elif defined(__MWERKS__) || defined(__cplusplus)
  38 #        define OS_INLINE static inline
  39 # else
  40 #        define OS_INLINE static __inline__
  41 # endif
  42 #endif
  43
  44 /* Generic byte swapping functions. */
  45
  46 OS_INLINE
  47 uint16_t
  48 _OSSwapInt16(
  49     uint16_t        data
  50 )
  51 {
  52     return ((data << 8) | (data >> 8));
  53 }
  54
  55 OS_INLINE
  56 uint32_t
  57 _OSSwapInt32(
  58     uint32_t        data
  59 )
  60 {
  61     __asm__ ("bswap   %0" : "+r" (data));
  62     return data;
  63 }
  64
  65 #if defined(__i386__)
  66 OS_INLINE
  67 uint64_t
  68 _OSSwapInt64(
  69     uint64_t        data
  70 )
  71 {
  72     __asm__ ("bswap   %%eax\n\t"
  73              "bswap   %%edx\n\t"
  74              "xchgl   %%eax, %%edx"
  75              : "+A" (data));
  76     return data;
  77 }
  78 #elif defined(__x86_64__)
  79 OS_INLINE
  80 uint64_t
  81 _OSSwapInt64(
  82     uint64_t        data
  83 )
  84 {
  85     __asm__ ("bswap   %0" : "+r" (data));
  86     return data;
  87 }
  88 #else
  89 #error Unknown architecture
  90 #endif
  91
  92 /* Functions for byte reversed loads. */
  93
  94 OS_INLINE
  95 uint16_t
  96 OSReadSwapInt16(
  97     const volatile void   * base,
  98     uintptr_t       byteOffset
  99 )
 100 {
 101     uint16_t result;
 102
 103     result = *(volatile uint16_t *)((uintptr_t)base + byteOffset);
 104     return _OSSwapInt16(result);
 105 }
 106
 107 OS_INLINE
 108 uint32_t
 109 OSReadSwapInt32(
 110     const volatile void   * base,
 111     uintptr_t       byteOffset
 112 )
 113 {
 114     uint32_t result;
 115
 116     result = *(volatile uint32_t *)((uintptr_t)base + byteOffset);
 117     return _OSSwapInt32(result);
 118 }
 119
 120 OS_INLINE
 121 uint64_t
 122 OSReadSwapInt64(
 123     const volatile void   * base,
 124     uintptr_t       byteOffset
 125 )
 126 {
 127     uint64_t result;
 128
 129     result = *(volatile uint64_t *)((uintptr_t)base + byteOffset);
 130     return _OSSwapInt64(result);
 131 }
 132
 133 /* Functions for byte reversed stores. */
 134
 135 OS_INLINE
 136 void
 137 OSWriteSwapInt16(
 138     volatile void   * base,
 139     uintptr_t       byteOffset,
 140     uint16_t        data
 141 )
 142 {
 143     *(volatile uint16_t *)((uintptr_t)base + byteOffset) = _OSSwapInt16(data);
 144 }
 145
 146 OS_INLINE
 147 void
 148 OSWriteSwapInt32(
 149     volatile void   * base,
 150     uintptr_t       byteOffset,
 151     uint32_t        data
 152 )
 153 {
 154     *(volatile uint32_t *)((uintptr_t)base + byteOffset) = _OSSwapInt32(data);
 155 }
 156
 157 OS_INLINE
 158 void
 159 OSWriteSwapInt64(
 160     volatile void    * base,
 161     uintptr_t        byteOffset,
 162     uint64_t         data
 163 )
 164 {
 165     *(volatile uint64_t *)((uintptr_t)base + byteOffset) = _OSSwapInt64(data);
 166 }
 167
 168 #endif /* ! _OS_OSBYTEORDERI386_H */