libkern/libkern/i386/OSByteOrder.h

   1 /*
   2  * Copyright (c) 1999-2003 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_OSREFERENCE_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
  10  * License may not be used to create, or enable the creation or
  11  * redistribution of, unlawful or unlicensed copies of an Apple operating
  12  * system, or to circumvent, violate, or enable the circumvention or
  13  * violation of, any terms of an Apple operating system software license
  14  * agreement.
  15  *
  16  * Please obtain a copy of the License at
  17  * http://www.opensource.apple.com/apsl/ and read it before using this
  18  * file.
  19  *
  20  * The Original Code and all software distributed under the License are
  21  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  22  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  23  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  24  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  25  * Please see the License for the specific language governing rights and
  26  * limitations under the License.
  27  *
  28  * @APPLE_LICENSE_OSREFERENCE_HEADER_END@
  29  */
  30
  31 #ifndef _OS_OSBYTEORDERI386_H
  32 #define _OS_OSBYTEORDERI386_H
  33
  34 #include <stdint.h>
  35
  36 #if !defined(OS_INLINE)
  37 #        define OS_INLINE static inline
  38 #endif
  39
  40 /* Generic byte swapping functions. */
  41
  42 OS_INLINE
  43 uint16_t
  44 _OSSwapInt16(
  45     uint16_t        data
  46 )
  47 {
  48     __asm__ ("xchgb %b0, %h0" : "+q" (data));
  49     return data;
  50 }
  51
  52 OS_INLINE
  53 uint32_t
  54 _OSSwapInt32(
  55     uint32_t        data
  56 )
  57 {
  58     __asm__ ("bswap %0" : "+r" (data));
  59     return data;
  60 }
  61
  62 OS_INLINE
  63 uint64_t
  64 _OSSwapInt64(
  65     uint64_t        data
  66 )
  67 {
  68     union {
  69         uint64_t ull;
  70         uint32_t ul[2];
  71     } u;
  72
  73     /* This actually generates the best code */
  74     u.ul[0] = data >> 32;
  75     u.ul[1] = data & 0xffffffff;
  76     u.ul[0] = _OSSwapInt32(u.ul[0]);
  77     u.ul[1] = _OSSwapInt32(u.ul[1]);
  78     return u.ull;
  79 }
  80
  81 /* Functions for byte reversed loads. */
  82
  83 OS_INLINE
  84 uint16_t
  85 OSReadSwapInt16(
  86     const volatile void   * base,
  87     uintptr_t       offset
  88 )
  89 {
  90     uint16_t result;
  91
  92     result = *(volatile uint16_t *)((uintptr_t)base + offset);
  93     return _OSSwapInt16(result);
  94 }
  95
  96 OS_INLINE
  97 uint32_t
  98 OSReadSwapInt32(
  99     const volatile void   * base,
 100     uintptr_t       offset
 101 )
 102 {
 103     uint32_t result;
 104
 105     result = *(volatile uint32_t *)((uintptr_t)base + offset);
 106     return _OSSwapInt32(result);
 107 }
 108
 109 OS_INLINE
 110 uint64_t
 111 OSReadSwapInt64(
 112     const volatile void   * base,
 113     uintptr_t       offset
 114 )
 115 {
 116     const volatile uint32_t * inp;
 117     union ullc {
 118         uint64_t     ull;
 119         uint32_t     ul[2];
 120     } outv;
 121
 122     inp = (const volatile uint32_t *)((uintptr_t)base + offset);
 123     outv.ul[0] = inp[1];
 124     outv.ul[1] = inp[0];
 125     outv.ul[0] = _OSSwapInt32(outv.ul[0]);
 126     outv.ul[1] = _OSSwapInt32(outv.ul[1]);
 127     return outv.ull;
 128 }
 129
 130 /* Functions for byte reversed stores. */
 131
 132 OS_INLINE
 133 void
 134 OSWriteSwapInt16(
 135     volatile void   * base,
 136     uintptr_t       offset,
 137     uint16_t        data
 138 )
 139 {
 140     *(volatile uint16_t *)((uintptr_t)base + offset) = _OSSwapInt16(data);
 141 }
 142
 143 OS_INLINE
 144 void
 145 OSWriteSwapInt32(
 146     volatile void   * base,
 147     uintptr_t       offset,
 148     uint32_t        data
 149 )
 150 {
 151     *(volatile uint32_t *)((uintptr_t)base + offset) = _OSSwapInt32(data);
 152 }
 153
 154 OS_INLINE
 155 void
 156 OSWriteSwapInt64(
 157     volatile void    * base,
 158     uintptr_t        offset,
 159     uint64_t         data
 160 )
 161 {
 162     *(volatile uint64_t *)((uintptr_t)base + offset) = _OSSwapInt64(data);
 163 }
 164
 165 #endif /* ! _OS_OSBYTEORDERI386_H */