libkern/libkern/i386/OSByteOrder.h

   1 /*
   2  * Copyright (c) 1999-2003 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_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. Please obtain a copy of the License at
  10  * http://www.opensource.apple.com/apsl/ and read it before using this
  11  * file.
  12  *
  13  * The Original Code and all software distributed under the License are
  14  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  15  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  16  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  17  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  18  * Please see the License for the specific language governing rights and
  19  * limitations under the License.
  20  *
  21  * @APPLE_LICENSE_HEADER_END@
  22  */
  23
  24 #ifndef _OS_OSBYTEORDERI386_H
  25 #define _OS_OSBYTEORDERI386_H
  26
  27 #include <stdint.h>
  28
  29 #if !defined(OS_INLINE)
  30 #        define OS_INLINE static inline
  31 #endif
  32
  33 /* Generic byte swapping functions. */
  34
  35 OS_INLINE
  36 uint16_t
  37 _OSSwapInt16(
  38     uint16_t        data
  39 )
  40 {
  41     __asm__ ("xchgb %b0, %h0" : "+q" (data));
  42     return data;
  43 }
  44
  45 OS_INLINE
  46 uint32_t
  47 _OSSwapInt32(
  48     uint32_t        data
  49 )
  50 {
  51     __asm__ ("bswap %0" : "+r" (data));
  52     return data;
  53 }
  54
  55 OS_INLINE
  56 uint64_t
  57 _OSSwapInt64(
  58     uint64_t        data
  59 )
  60 {
  61     union {
  62         uint64_t ull;
  63         uint32_t ul[2];
  64     } u;
  65
  66     /* This actually generates the best code */
  67     u.ul[0] = data >> 32;
  68     u.ul[1] = data & 0xffffffff;
  69     u.ul[0] = _OSSwapInt32(u.ul[0]);
  70     u.ul[1] = _OSSwapInt32(u.ul[1]);
  71     return u.ull;
  72 }
  73
  74 /* Functions for byte reversed loads. */
  75
  76 OS_INLINE
  77 uint16_t
  78 OSReadSwapInt16(
  79     const volatile void   * base,
  80     uintptr_t       offset
  81 )
  82 {
  83     uint16_t result;
  84
  85     result = *(volatile uint16_t *)((uintptr_t)base + offset);
  86     return _OSSwapInt16(result);
  87 }
  88
  89 OS_INLINE
  90 uint32_t
  91 OSReadSwapInt32(
  92     const volatile void   * base,
  93     uintptr_t       offset
  94 )
  95 {
  96     uint32_t result;
  97
  98     result = *(volatile uint32_t *)((uintptr_t)base + offset);
  99     return _OSSwapInt32(result);
 100 }
 101
 102 OS_INLINE
 103 uint64_t
 104 OSReadSwapInt64(
 105     const volatile void   * base,
 106     uintptr_t       offset
 107 )
 108 {
 109     const volatile uint32_t * inp;
 110     union ullc {
 111         uint64_t     ull;
 112         uint32_t     ul[2];
 113     } outv;
 114
 115     inp = (const volatile uint32_t *)((uintptr_t)base + offset);
 116     outv.ul[0] = inp[1];
 117     outv.ul[1] = inp[0];
 118     outv.ul[0] = _OSSwapInt32(outv.ul[0]);
 119     outv.ul[1] = _OSSwapInt32(outv.ul[1]);
 120     return outv.ull;
 121 }
 122
 123 /* Functions for byte reversed stores. */
 124
 125 OS_INLINE
 126 void
 127 OSWriteSwapInt16(
 128     volatile void   * base,
 129     uintptr_t       offset,
 130     uint16_t        data
 131 )
 132 {
 133     *(volatile uint16_t *)((uintptr_t)base + offset) = _OSSwapInt16(data);
 134 }
 135
 136 OS_INLINE
 137 void
 138 OSWriteSwapInt32(
 139     volatile void   * base,
 140     uintptr_t       offset,
 141     uint32_t        data
 142 )
 143 {
 144     *(volatile uint32_t *)((uintptr_t)base + offset) = _OSSwapInt32(data);
 145 }
 146
 147 OS_INLINE
 148 void
 149 OSWriteSwapInt64(
 150     volatile void    * base,
 151     uintptr_t        offset,
 152     uint64_t         data
 153 )
 154 {
 155     *(volatile uint64_t *)((uintptr_t)base + offset) = _OSSwapInt64(data);
 156 }
 157
 158 #endif /* ! _OS_OSBYTEORDERI386_H */