libkern/libkern/i386/OSByteOrder.h

   1 /*
   2  * Copyright (c) 1999-2005 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * The contents of this file constitute Original Code as defined in and
   7  * are subject to the Apple Public Source License Version 1.1 (the
   8  * "License").  You may not use this file except in compliance with the
   9  * License.  Please obtain a copy of the License at
  10  * http://www.apple.com/publicsource and read it before using this file.
  11  *
  12  * This Original Code and all software distributed under the License are
  13  * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  14  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  15  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  16  * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT.  Please see the
  17  * License for the specific language governing rights and limitations
  18  * under the License.
  19  *
  20  * @APPLE_LICENSE_HEADER_END@
  21  */
  22
  23 #ifndef _OS_OSBYTEORDERI386_H
  24 #define _OS_OSBYTEORDERI386_H
  25
  26 #include <stdint.h>
  27
  28 #if !defined(OS_INLINE)
  29 # if defined(__STDC_VERSION__) && __STDC_VERSION__ >= 199901L
  30 #        define OS_INLINE static inline
  31 # elif defined(__MWERKS__) || defined(__cplusplus)
  32 #        define OS_INLINE static inline
  33 # else
  34 #        define OS_INLINE static __inline__
  35 # endif
  36 #endif
  37
  38 /* Generic byte swapping functions. */
  39
  40 OS_INLINE
  41 uint16_t
  42 _OSSwapInt16(
  43     uint16_t        data
  44 )
  45 {
  46     return ((data << 8) | (data >> 8));
  47 }
  48
  49 OS_INLINE
  50 uint32_t
  51 _OSSwapInt32(
  52     uint32_t        data
  53 )
  54 {
  55     __asm__ ("bswap   %0" : "+r" (data));
  56     return data;
  57 }
  58
  59 #if defined(__i386__)
  60 OS_INLINE
  61 uint64_t
  62 _OSSwapInt64(
  63     uint64_t        data
  64 )
  65 {
  66     __asm__ ("bswap   %%eax\n\t"
  67              "bswap   %%edx\n\t"
  68              "xchgl   %%eax, %%edx"
  69              : "+A" (data));
  70     return data;
  71 }
  72 #elif defined(__x86_64__)
  73 OS_INLINE
  74 uint64_t
  75 _OSSwapInt64(
  76     uint64_t        data
  77 )
  78 {
  79     __asm__ ("bswap   %0" : "+r" (data));
  80     return data;
  81 }
  82 #else
  83 #error Unknown architecture
  84 #endif
  85
  86 /* Functions for byte reversed loads. */
  87
  88 OS_INLINE
  89 uint16_t
  90 OSReadSwapInt16(
  91     const volatile void   * base,
  92     uintptr_t       byteOffset
  93 )
  94 {
  95     uint16_t result;
  96
  97     result = *(volatile uint16_t *)((uintptr_t)base + byteOffset);
  98     return _OSSwapInt16(result);
  99 }
 100
 101 OS_INLINE
 102 uint32_t
 103 OSReadSwapInt32(
 104     const volatile void   * base,
 105     uintptr_t       byteOffset
 106 )
 107 {
 108     uint32_t result;
 109
 110     result = *(volatile uint32_t *)((uintptr_t)base + byteOffset);
 111     return _OSSwapInt32(result);
 112 }
 113
 114 OS_INLINE
 115 uint64_t
 116 OSReadSwapInt64(
 117     const volatile void   * base,
 118     uintptr_t       byteOffset
 119 )
 120 {
 121     uint64_t result;
 122
 123     result = *(volatile uint64_t *)((uintptr_t)base + byteOffset);
 124     return _OSSwapInt64(result);
 125 }
 126
 127 /* Functions for byte reversed stores. */
 128
 129 OS_INLINE
 130 void
 131 OSWriteSwapInt16(
 132     volatile void   * base,
 133     uintptr_t       byteOffset,
 134     uint16_t        data
 135 )
 136 {
 137     *(volatile uint16_t *)((uintptr_t)base + byteOffset) = _OSSwapInt16(data);
 138 }
 139
 140 OS_INLINE
 141 void
 142 OSWriteSwapInt32(
 143     volatile void   * base,
 144     uintptr_t       byteOffset,
 145     uint32_t        data
 146 )
 147 {
 148     *(volatile uint32_t *)((uintptr_t)base + byteOffset) = _OSSwapInt32(data);
 149 }
 150
 151 OS_INLINE
 152 void
 153 OSWriteSwapInt64(
 154     volatile void    * base,
 155     uintptr_t        byteOffset,
 156     uint64_t         data
 157 )
 158 {
 159     *(volatile uint64_t *)((uintptr_t)base + byteOffset) = _OSSwapInt64(data);
 160 }
 161
 162 #endif /* ! _OS_OSBYTEORDERI386_H */