libkern/libkern/i386/OSByteOrder.h

   1 /*
   2  * Copyright (c) 1999-2003 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 #        define OS_INLINE static inline
  36 #endif
  37
  38 /* Generic byte swapping functions. */
  39
  40 OS_INLINE
  41 uint16_t
  42 _OSSwapInt16(
  43     uint16_t        data
  44 )
  45 {
  46     __asm__ ("xchgb %b0, %h0" : "+q" (data));
  47     return data;
  48 }
  49
  50 OS_INLINE
  51 uint32_t
  52 _OSSwapInt32(
  53     uint32_t        data
  54 )
  55 {
  56     __asm__ ("bswap %0" : "+r" (data));
  57     return data;
  58 }
  59
  60 OS_INLINE
  61 uint64_t
  62 _OSSwapInt64(
  63     uint64_t        data
  64 )
  65 {
  66     union {
  67         uint64_t ull;
  68         uint32_t ul[2];
  69     } u;
  70
  71     /* This actually generates the best code */
  72     u.ul[0] = data >> 32;
  73     u.ul[1] = data & 0xffffffff;
  74     u.ul[0] = _OSSwapInt32(u.ul[0]);
  75     u.ul[1] = _OSSwapInt32(u.ul[1]);
  76     return u.ull;
  77 }
  78
  79 /* Functions for byte reversed loads. */
  80
  81 OS_INLINE
  82 uint16_t
  83 OSReadSwapInt16(
  84     const volatile void   * base,
  85     uintptr_t       offset
  86 )
  87 {
  88     uint16_t result;
  89
  90     result = *(volatile uint16_t *)((uintptr_t)base + offset);
  91     return _OSSwapInt16(result);
  92 }
  93
  94 OS_INLINE
  95 uint32_t
  96 OSReadSwapInt32(
  97     const volatile void   * base,
  98     uintptr_t       offset
  99 )
 100 {
 101     uint32_t result;
 102
 103     result = *(volatile uint32_t *)((uintptr_t)base + offset);
 104     return _OSSwapInt32(result);
 105 }
 106
 107 OS_INLINE
 108 uint64_t
 109 OSReadSwapInt64(
 110     const volatile void   * base,
 111     uintptr_t       offset
 112 )
 113 {
 114     const volatile uint32_t * inp;
 115     union ullc {
 116         uint64_t     ull;
 117         uint32_t     ul[2];
 118     } outv;
 119
 120     inp = (const volatile uint32_t *)((uintptr_t)base + offset);
 121     outv.ul[0] = inp[1];
 122     outv.ul[1] = inp[0];
 123     outv.ul[0] = _OSSwapInt32(outv.ul[0]);
 124     outv.ul[1] = _OSSwapInt32(outv.ul[1]);
 125     return outv.ull;
 126 }
 127
 128 /* Functions for byte reversed stores. */
 129
 130 OS_INLINE
 131 void
 132 OSWriteSwapInt16(
 133     volatile void   * base,
 134     uintptr_t       offset,
 135     uint16_t        data
 136 )
 137 {
 138     *(volatile uint16_t *)((uintptr_t)base + offset) = _OSSwapInt16(data);
 139 }
 140
 141 OS_INLINE
 142 void
 143 OSWriteSwapInt32(
 144     volatile void   * base,
 145     uintptr_t       offset,
 146     uint32_t        data
 147 )
 148 {
 149     *(volatile uint32_t *)((uintptr_t)base + offset) = _OSSwapInt32(data);
 150 }
 151
 152 OS_INLINE
 153 void
 154 OSWriteSwapInt64(
 155     volatile void    * base,
 156     uintptr_t        offset,
 157     uint64_t         data
 158 )
 159 {
 160     *(volatile uint64_t *)((uintptr_t)base + offset) = _OSSwapInt64(data);
 161 }
 162
 163 #endif /* ! _OS_OSBYTEORDERI386_H */