libkern/libkern/OSAtomic.h

   1 /*
   2  * Copyright (c) 2000 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  * Copyright (c) 1999 Apple Computer, Inc.  All rights reserved.
  25  *
  26  * HISTORY
  27  *
  28  */
  29
  30 #ifndef _OS_OSATOMIC_H
  31 #define _OS_OSATOMIC_H
  32
  33 #include <libkern/OSBase.h>
  34
  35 #if defined(__cplusplus)
  36 extern "C" {
  37 #endif
  38
  39 /*! @function OSCompareAndSwap
  40     @abstract Compare and swap operation, performed atomically with respect to all devices that participate in the coherency architecture of the platform.
  41     @discussion The OSCompareAndSwap function compares the value at the specified address with oldVal. The value of newValue is written to the address only if oldValue and the value at the address are equal. OSCompareAndSwap returns true if newValue is written to the address; otherwise, it returns false.
  42
  43     This function guarantees atomicity only with main system memory. It is specifically unsuitable for use on noncacheable memory such as that in devices; this function cannot guarantee atomicity, for example, on memory mapped from a PCI device.
  44     @param oldValue The value to compare at address.
  45     @param newValue The value to write to address if oldValue compares true.
  46     @param address The 4-byte aligned address of the data to update atomically.
  47     @result true if newValue was written to the address. */
  48
  49 extern Boolean OSCompareAndSwap( UInt32 oldValue, UInt32 newValue, UInt32 * address );
  50
  51 /*! @function OSAddAtomic
  52     @abstract 32-bit add operation, performed atomically with respect to all devices that participate in the coherency architecture of the platform.
  53     @discussion The OSAddAtomic function adds the specified amount to the value at the specified address and returns the original value.
  54
  55     This function guarantees atomicity only with main system memory. It is specifically unsuitable for use on noncacheable memory such as that in devices; this function cannot guarantee atomicity, for example, on memory mapped from a PCI device.
  56     @param amount The amount to add.
  57     @param address The 4-byte aligned address of the value to update atomically.
  58     @result The value before the addition */
  59
  60 extern SInt32   OSAddAtomic(SInt32 amount, SInt32 * address);
  61
  62 /*! @function OSAddAtomic16
  63     @abstract 16-bit add operation, performed atomically with respect to all devices that participate in the coherency architecture of the platform.
  64     @discussion The OSAddAtomic16 function adds the specified amount to the value at the specified address and returns the original value.
  65
  66     This function guarantees atomicity only with main system memory. It is specifically unsuitable for use on noncacheable memory such as that in devices; this function cannot guarantee atomicity, for example, on memory mapped from a PCI device.
  67     @param amount The amount to add.
  68     @param address The 2-byte aligned address of the value to update atomically.
  69     @result The value before the addition */
  70
  71 extern SInt16   OSAddAtomic16(SInt32 amount, SInt16 * address);
  72
  73 /*! @function OSAddAtomic8
  74     @abstract 8-bit add operation, performed atomically with respect to all devices that participate in the coherency architecture of the platform.
  75     @discussion The OSAddAtomic8 function adds the specified amount to the value at the specified address and returns the original value.
  76
  77     This function guarantees atomicity only with main system memory. It is specifically unsuitable for use on noncacheable memory such as that in devices; this function cannot guarantee atomicity, for example, on memory mapped from a PCI device.
  78     @param amount The amount to add.
  79     @param address The address of the value to update atomically.
  80     @result The value before the addition */
  81
  82 extern SInt8    OSAddAtomic8(SInt32 amount, SInt8 * address);
  83
  84 /*! @function OSIncrementAtomic
  85     @abstract 32-bit increment operation, performed atomically with respect to all devices that participate in the coherency architecture of the platform.
  86     @discussion The OSIncrementAtomic function increments the value at the specified address by one and returns the original value.
  87
  88     This function guarantees atomicity only with main system memory. It is specifically unsuitable for use on noncacheable memory such as that in devices; this function cannot guarantee atomicity, for example, on memory mapped from a PCI device.
  89     @param address The 4-byte aligned address of the value to update atomically.
  90     @result The value before the increment. */
  91
  92 extern SInt32   OSIncrementAtomic(SInt32 * address);
  93
  94 /*! @function OSIncrementAtomic16
  95     @abstract 16-bit increment operation, performed atomically with respect to all devices that participate in the coherency architecture of the platform.
  96     @discussion The OSIncrementAtomic16 function increments the value at the specified address by one and returns the original value.
  97
  98     This function guarantees atomicity only with main system memory. It is specifically unsuitable for use on noncacheable memory such as that in devices; this function cannot guarantee atomicity, for example, on memory mapped from a PCI device.
  99     @param address The 2-byte aligned address of the value to update atomically.
 100     @result The value before the increment. */
 101
 102 extern SInt16   OSIncrementAtomic16(SInt16 * address);
 103
 104 /*! @function OSIncrementAtomic8
 105     @abstract 8-bit increment operation, performed atomically with respect to all devices that participate in the coherency architecture of the platform.
 106     @discussion The OSIncrementAtomic8 function increments the value at the specified address by one and returns the original value.
 107
 108     This function guarantees atomicity only with main system memory. It is specifically unsuitable for use on noncacheable memory such as that in devices; this function cannot guarantee atomicity, for example, on memory mapped from a PCI device.
 109     @param address The address of the value to update atomically.
 110     @result The value before the increment. */
 111
 112 extern SInt8    OSIncrementAtomic8(SInt8 * address);
 113
 114 /*! @function OSDecrementAtomic
 115     @abstract 32-bit decrement operation, performed atomically with respect to all devices that participate in the coherency architecture of the platform.
 116     @discussion The OSDecrementAtomic function decrements the value at the specified address by one and returns the original value.
 117
 118     This function guarantees atomicity only with main system memory. It is specifically unsuitable for use on noncacheable memory such as that in devices; this function cannot guarantee atomicity, for example, on memory mapped from a PCI device.
 119     @param address The 4-byte aligned address of the value to update atomically.
 120     @result The value before the decrement. */
 121
 122 extern SInt32   OSDecrementAtomic(SInt32 * address);
 123
 124 /*! @function OSDecrementAtomic16
 125     @abstract 16-bit decrement operation, performed atomically with respect to all devices that participate in the coherency architecture of the platform.
 126     @discussion The OSDecrementAtomic16 function decrements the value at the specified address by one and returns the original value.
 127
 128     This function guarantees atomicity only with main system memory. It is specifically unsuitable for use on noncacheable memory such as that in devices; this function cannot guarantee atomicity, for example, on memory mapped from a PCI device.
 129     @param address The 2-byte aligned address of the value to update atomically.
 130     @result The value before the decrement. */
 131
 132 extern SInt16   OSDecrementAtomic16(SInt16 * address);
 133
 134 /*! @function OSDecrementAtomic8
 135     @abstract 8-bit decrement operation, performed atomically with respect to all devices that participate in the coherency architecture of the platform.
 136     @discussion The OSDecrementAtomic8 function decrements the value at the specified address by one and returns the original value.
 137
 138     This function guarantees atomicity only with main system memory. It is specifically unsuitable for use on noncacheable memory such as that in devices; this function cannot guarantee atomicity, for example, on memory mapped from a PCI device.
 139     @param address The address of the value to update atomically.
 140     @result The value before the decrement. */
 141
 142 extern SInt8    OSDecrementAtomic8(SInt8 * address);
 143
 144 /*! @function OSBitAndAtomic
 145     @abstract 32-bit logical and operation, performed atomically with respect to all devices that participate in the coherency architecture of the platform.
 146     @discussion The OSBitAndAtomic function logically ands the bits of the specified mask into the value at the specified address and returns the original value.
 147
 148     This function guarantees atomicity only with main system memory. It is specifically unsuitable for use on noncacheable memory such as that in devices; this function cannot guarantee atomicity, for example, on memory mapped from a PCI device.
 149     @param mask The mask to logically and with the value.
 150     @param address The 4-byte aligned address of the value to update atomically.
 151     @result The value before the bitwise operation */
 152
 153 extern UInt32   OSBitAndAtomic(UInt32 mask, UInt32 * address);
 154
 155 /*! @function OSBitAndAtomic16
 156     @abstract 16-bit logical and operation, performed atomically with respect to all devices that participate in the coherency architecture of the platform.
 157     @discussion The OSBitAndAtomic16 function logically ands the bits of the specified mask into the value at the specified address and returns the original value.
 158
 159     This function guarantees atomicity only with main system memory. It is specifically unsuitable for use on noncacheable memory such as that in devices; this function cannot guarantee atomicity, for example, on memory mapped from a PCI device.
 160     @param mask The mask to logically and with the value.
 161     @param address The 2-byte aligned address of the value to update atomically.
 162     @result The value before the bitwise operation. */
 163
 164 extern UInt16   OSBitAndAtomic16(UInt32 mask, UInt16 * address);
 165
 166 /*! @function OSBitAndAtomic8
 167     @abstract 8-bit logical and operation, performed atomically with respect to all devices that participate in the coherency architecture of the platform.
 168     @discussion The OSBitAndAtomic8 function logically ands the bits of the specified mask into the value at the specified address and returns the original value.
 169
 170     This function guarantees atomicity only with main system memory. It is specifically unsuitable for use on noncacheable memory such as that in devices; this function cannot guarantee atomicity, for example, on memory mapped from a PCI device.
 171     @param mask The mask to logically and with the value.
 172     @param address The address of the value to update atomically.
 173     @result The value before the bitwise operation. */
 174
 175 extern UInt8    OSBitAndAtomic8(UInt32 mask, UInt8 * address);
 176
 177 /*! @function OSBitOrAtomic
 178     @abstract 32-bit logical or operation, performed atomically with respect to all devices that participate in the coherency architecture of the platform.
 179     @discussion The OSBitOrAtomic function logically ors the bits of the specified mask into the value at the specified address and returns the original value.
 180
 181     This function guarantees atomicity only with main system memory. It is specifically unsuitable for use on noncacheable memory such as that in devices; this function cannot guarantee atomicity, for example, on memory mapped from a PCI device.
 182     @param mask The mask to logically or with the value.
 183     @param address The 4-byte aligned address of the value to update atomically.
 184     @result The value before the bitwise operation. */
 185
 186 extern UInt32   OSBitOrAtomic(UInt32 mask, UInt32 * address);
 187
 188 /*! @function OSBitOrAtomic16
 189     @abstract 16-bit logical or operation, performed atomically with respect to all devices that participate in the coherency architecture of the platform.
 190     @discussion The OSBitOrAtomic16 function logically ors the bits of the specified mask into the value at the specified address and returns the original value.
 191
 192     This function guarantees atomicity only with main system memory. It is specifically unsuitable for use on noncacheable memory such as that in devices; this function cannot guarantee atomicity, for example, on memory mapped from a PCI device.
 193     @param mask The mask to logically or with the value.
 194     @param address The 2-byte aligned address of the value to update atomically.
 195     @result The value before the bitwise operation. */
 196
 197 extern UInt16   OSBitOrAtomic16(UInt32 mask, UInt16 * address);
 198
 199 /*! @function OSBitOrAtomic8
 200     @abstract 8-bit logical or operation, performed atomically with respect to all devices that participate in the coherency architecture of the platform.
 201
 202     This function guarantees atomicity only with main system memory. It is specifically unsuitable for use on noncacheable memory such as that in devices; this function cannot guarantee atomicity, for example, on memory mapped from a PCI device.
 203     @discussion The OSBitOrAtomic8 function logically ors the bits of the specified mask into the value at the specified address and returns the original value.
 204     @param mask The mask to logically or with the value.
 205     @param address The address of the value to update atomically.
 206     @result The value before the bitwise operation. */
 207
 208 extern UInt8    OSBitOrAtomic8(UInt32 mask, UInt8 * address);
 209
 210 /*! @function OSBitXorAtomic
 211     @abstract 32-bit logical xor operation, performed atomically with respect to all devices that participate in the coherency architecture of the platform.
 212
 213     This function guarantees atomicity only with main system memory. It is specifically unsuitable for use on noncacheable memory such as that in devices; this function cannot guarantee atomicity, for example, on memory mapped from a PCI device.
 214     @discussion The OSBitXorAtomic function logically xors the bits of the specified mask into the value at the specified address and returns the original value.
 215     @param mask The mask to logically or with the value.
 216     @param address The 4-byte aligned address of the value to update atomically.
 217     @result The value before the bitwise operation. */
 218
 219 extern UInt32   OSBitXorAtomic(UInt32 mask, UInt32 * address);
 220
 221 /*! @function OSBitXorAtomic16
 222     @abstract 16-bit logical xor operation, performed atomically with respect to all devices that participate in the coherency architecture of the platform.
 223     @discussion The OSBitXorAtomic16 function logically xors the bits of the specified mask into the value at the specified address and returns the original value.
 224
 225     This function guarantees atomicity only with main system memory. It is specifically unsuitable for use on noncacheable memory such as that in devices; this function cannot guarantee atomicity, for example, on memory mapped from a PCI device.
 226     @param mask The mask to logically or with the value.
 227     @param address The 2-byte aligned address of the value to update atomically.
 228     @result The value before the bitwise operation. */
 229
 230 extern UInt16   OSBitXorAtomic16(UInt32 mask, UInt16 * address);
 231
 232 /*! @function OSBitXorAtomic8
 233     @abstract 8-bit logical xor operation, performed atomically with respect to all devices that participate in the coherency architecture of the platform.
 234
 235     This function guarantees atomicity only with main system memory. It is specifically unsuitable for use on noncacheable memory such as that in devices; this function cannot guarantee atomicity, for example, on memory mapped from a PCI device.
 236     @discussion The OSBitXorAtomic8 function logically xors the bits of the specified mask into the value at the specified address and returns the original value.
 237     @param mask The mask to logically or with the value.
 238     @param address The address of the value to update atomically.
 239     @result The value before the bitwise operation. */
 240
 241 extern UInt8    OSBitXorAtomic8(UInt32 mask, UInt8 * address);
 242
 243 /*! @function OSTestAndSet
 244     @abstract Bit test and set operation, performed atomically with respect to all devices that participate in the coherency architecture of the platform.
 245
 246     This function guarantees atomicity only with main system memory. It is specifically unsuitable for use on noncacheable memory such as that in devices; this function cannot guarantee atomicity, for example, on memory mapped from a PCI device.
 247     @discussion The OSTestAndSet function sets a single bit in a byte at a specified address. It returns true if the bit was already set, false otherwise.
 248     @param bit The bit number in the range 0 through 7.
 249     @param address The address of the byte to update atomically.
 250     @result true if the bit was already set, false otherwise. */
 251
 252 extern Boolean  OSTestAndSet(UInt32 bit, UInt8 * startAddress);
 253
 254 /*! @function OSTestAndClear
 255     @abstract Bit test and clear operation, performed atomically with respect to all devices that participate in the coherency architecture of the platform.
 256     @discussion The OSTestAndClear function clears a single bit in a byte at a specified address. It returns true if the bit was already clear, false otherwise.
 257
 258     This function guarantees atomicity only with main system memory. It is specifically unsuitable for use on noncacheable memory such as that in devices; this function cannot guarantee atomicity, for example, on memory mapped from a PCI device.
 259     @param bit The bit number in the range 0 through 7.
 260     @param address The address of the byte to update atomically.
 261     @result true if the bit was already clear, false otherwise. */
 262
 263 extern Boolean  OSTestAndClear(UInt32 bit, UInt8 * startAddress);
 264
 265 /*! @function OSEnqueueAtomic
 266     @abstract Singly linked list head insertion, performed atomically with respect to all devices that participate in the coherency architecture of the platform.
 267     @discussion The OSEnqueueAtomic function places an element at the head of a single linked list, which is specified with the address of a head pointer, listHead. The element structure has a next field whose offset is specified.
 268
 269     This function guarantees atomicity only with main system memory. It is specifically unsuitable for use on noncacheable memory such as that in devices; this function cannot guarantee atomicity, for example, on memory mapped from a PCI device.
 270     @param listHead The address of a head pointer for the list .
 271     @param element The list element to insert at the head of the list.
 272     @param elementNextFieldOffset The byte offset into the element where a pointer to the next element in the list is stored. */
 273
 274 extern void     OSEnqueueAtomic(void ** listHead, void * element,
 275                                 SInt32 elementNextFieldOffset);
 276
 277 /*! @function OSDequeueAtomic
 278     @abstract Singly linked list element head removal, performed atomically with respect to all devices that participate in the coherency architecture of the platform.
 279     @discussion The OSDequeueAtomic function removes an element from the head of a single linked list, which is specified with the address of a head pointer, listHead. The element structure has a next field whose offset is specified.
 280
 281     This function guarantees atomicity only with main system memory. It is specifically unsuitable for use on noncacheable memory such as that in devices; this function cannot guarantee atomicity, for example, on memory mapped from a PCI device.
 282     @param listHead The address of a head pointer for the list .
 283     @param elementNextFieldOffset The byte offset into the element where a pointer to the next element in the list is stored.
 284     @result A removed element, or zero if the list is empty. */
 285
 286 extern void *   OSDequeueAtomic(void ** listHead,
 287                                 SInt32 elementNextFieldOffset);
 288
 289 /*! @function OSSynchronizeIO
 290     @abstract The OSSynchronizeIO routine ensures orderly load and store operations to noncached memory mapped I/O devices.
 291     @discussion The OSSynchronizeIO routine ensures orderly load and store operations to noncached memory mapped I/O devices. It executes the eieio instruction on PowerPC processors. */
 292
 293 static __inline__ void OSSynchronizeIO(void)
 294 {
 295 #if defined(__ppc__)
 296         __asm__ ("eieio");
 297 #endif
 298 }
 299
 300 #if defined(__cplusplus)
 301 }
 302 #endif
 303
 304 #endif /* ! _OS_OSATOMIC_H */