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  * 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 #        define OS_INLINE static inline
  30 #endif
  31
  32 /* Generic byte swapping functions. */
  33
  34 OS_INLINE
  35 uint16_t
  36 _OSSwapInt16(
  37     uint16_t        data
  38 )
  39 {
  40     __asm__ ("xchgb %b0, %h0" : "+q" (data));
  41     return data;
  42 }
  43
  44 OS_INLINE
  45 uint32_t
  46 _OSSwapInt32(
  47     uint32_t        data
  48 )
  49 {
  50     __asm__ ("bswap %0" : "+r" (data));
  51     return data;
  52 }
  53
  54 OS_INLINE
  55 uint64_t
  56 _OSSwapInt64(
  57     uint64_t        data
  58 )
  59 {
  60     union {
  61         uint64_t ull;
  62         uint32_t ul[2];
  63     } u;
  64
  65     /* This actually generates the best code */
  66     u.ul[0] = data >> 32;
  67     u.ul[1] = data & 0xffffffff;
  68     u.ul[0] = _OSSwapInt32(u.ul[0]);
  69     u.ul[1] = _OSSwapInt32(u.ul[1]);
  70     return u.ull;
  71 }
  72
  73 /* Functions for byte reversed loads. */
  74
  75 OS_INLINE
  76 uint16_t
  77 OSReadSwapInt16(
  78     const volatile void   * base,
  79     uintptr_t       offset
  80 )
  81 {
  82     uint16_t result;
  83
  84     result = *(volatile uint16_t *)((uintptr_t)base + offset);
  85     return _OSSwapInt16(result);
  86 }
  87
  88 OS_INLINE
  89 uint32_t
  90 OSReadSwapInt32(
  91     const volatile void   * base,
  92     uintptr_t       offset
  93 )
  94 {
  95     uint32_t result;
  96
  97     result = *(volatile uint32_t *)((uintptr_t)base + offset);
  98     return _OSSwapInt32(result);
  99 }
 100
 101 OS_INLINE
 102 uint64_t
 103 OSReadSwapInt64(
 104     const volatile void   * base,
 105     uintptr_t       offset
 106 )
 107 {
 108     const volatile uint32_t * inp;
 109     union ullc {
 110         uint64_t     ull;
 111         uint32_t     ul[2];
 112     } outv;
 113
 114     inp = (const volatile uint32_t *)((uintptr_t)base + offset);
 115     outv.ul[0] = inp[1];
 116     outv.ul[1] = inp[0];
 117     outv.ul[0] = _OSSwapInt32(outv.ul[0]);
 118     outv.ul[1] = _OSSwapInt32(outv.ul[1]);
 119     return outv.ull;
 120 }
 121
 122 /* Functions for byte reversed stores. */
 123
 124 OS_INLINE
 125 void
 126 OSWriteSwapInt16(
 127     volatile void   * base,
 128     uintptr_t       offset,
 129     uint16_t        data
 130 )
 131 {
 132     *(volatile uint16_t *)((uintptr_t)base + offset) = _OSSwapInt16(data);
 133 }
 134
 135 OS_INLINE
 136 void
 137 OSWriteSwapInt32(
 138     volatile void   * base,
 139     uintptr_t       offset,
 140     uint32_t        data
 141 )
 142 {
 143     *(volatile uint32_t *)((uintptr_t)base + offset) = _OSSwapInt32(data);
 144 }
 145
 146 OS_INLINE
 147 void
 148 OSWriteSwapInt64(
 149     volatile void    * base,
 150     uintptr_t        offset,
 151     uint64_t         data
 152 )
 153 {
 154     *(volatile uint64_t *)((uintptr_t)base + offset) = _OSSwapInt64(data);
 155 }
 156
 157 #endif /* ! _OS_OSBYTEORDERI386_H */