1 | /** @file
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2 | Implementation of synchronization functions.
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3 |
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4 | Copyright (c) 2006 - 2018, Intel Corporation. All rights reserved.<BR>
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5 | SPDX-License-Identifier: BSD-2-Clause-Patent
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6 |
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7 | **/
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8 |
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9 | #include "BaseSynchronizationLibInternals.h"
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10 |
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11 | /**
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12 | Microsoft Visual Studio 7.1 Function Prototypes for read write barrier Intrinsics.
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13 | **/
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14 |
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15 | void _ReadWriteBarrier (void);
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16 | #pragma intrinsic(_ReadWriteBarrier)
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17 |
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18 |
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19 | #define SPIN_LOCK_RELEASED ((UINTN) 1)
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20 | #define SPIN_LOCK_ACQUIRED ((UINTN) 2)
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21 |
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22 | /**
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23 | Retrieves the architecture specific spin lock alignment requirements for
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24 | optimal spin lock performance.
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25 |
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26 | This function retrieves the spin lock alignment requirements for optimal
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27 | performance on a given CPU architecture. The spin lock alignment is byte alignment.
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28 | It must be a power of two and is returned by this function. If there are no alignment
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29 | requirements, then 1 must be returned. The spin lock synchronization
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30 | functions must function correctly if the spin lock size and alignment values
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31 | returned by this function are not used at all. These values are hints to the
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32 | consumers of the spin lock synchronization functions to obtain optimal spin
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33 | lock performance.
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34 |
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35 | @return The architecture specific spin lock alignment.
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36 |
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37 | **/
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38 | UINTN
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39 | EFIAPI
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40 | GetSpinLockProperties (
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41 | VOID
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42 | )
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43 | {
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44 | return InternalGetSpinLockProperties ();
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45 | }
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46 |
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47 | /**
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48 | Initializes a spin lock to the released state and returns the spin lock.
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49 |
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50 | This function initializes the spin lock specified by SpinLock to the released
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51 | state, and returns SpinLock. Optimal performance can be achieved by calling
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52 | GetSpinLockProperties() to determine the size and alignment requirements for
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53 | SpinLock.
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54 |
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55 | If SpinLock is NULL, then ASSERT().
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56 |
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57 | @param SpinLock A pointer to the spin lock to initialize to the released
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58 | state.
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59 |
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60 | @return SpinLock is in release state.
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61 |
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62 | **/
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63 | SPIN_LOCK *
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64 | EFIAPI
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65 | InitializeSpinLock (
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66 | OUT SPIN_LOCK *SpinLock
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67 | )
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68 | {
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69 | ASSERT (SpinLock != NULL);
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70 |
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71 | _ReadWriteBarrier();
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72 | *SpinLock = SPIN_LOCK_RELEASED;
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73 | _ReadWriteBarrier();
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74 |
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75 | return SpinLock;
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76 | }
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77 |
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78 | /**
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79 | Waits until a spin lock can be placed in the acquired state.
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80 |
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81 | This function checks the state of the spin lock specified by SpinLock. If
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82 | SpinLock is in the released state, then this function places SpinLock in the
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83 | acquired state and returns SpinLock. Otherwise, this function waits
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84 | indefinitely for the spin lock to be released, and then places it in the
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85 | acquired state and returns SpinLock. All state transitions of SpinLock must
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86 | be performed using MP safe mechanisms.
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87 |
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88 | If SpinLock is NULL, then ASSERT().
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89 | If SpinLock was not initialized with InitializeSpinLock(), then ASSERT().
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90 | If PcdSpinLockTimeout is not zero, and SpinLock is can not be acquired in
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91 | PcdSpinLockTimeout microseconds, then ASSERT().
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92 |
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93 | @param SpinLock A pointer to the spin lock to place in the acquired state.
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94 |
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95 | @return SpinLock acquired the lock.
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96 |
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97 | **/
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98 | SPIN_LOCK *
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99 | EFIAPI
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100 | AcquireSpinLock (
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101 | IN OUT SPIN_LOCK *SpinLock
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102 | )
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103 | {
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104 | UINT64 Current;
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105 | UINT64 Previous;
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106 | UINT64 Total;
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107 | UINT64 Start;
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108 | UINT64 End;
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109 | UINT64 Timeout;
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110 | INT64 Cycle;
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111 | INT64 Delta;
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112 |
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113 | if (PcdGet32 (PcdSpinLockTimeout) == 0) {
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114 | while (!AcquireSpinLockOrFail (SpinLock)) {
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115 | CpuPause ();
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116 | }
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117 | } else if (!AcquireSpinLockOrFail (SpinLock)) {
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118 | //
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119 | // Get the current timer value
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120 | //
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121 | Current = GetPerformanceCounter();
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122 |
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123 | //
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124 | // Initialize local variables
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125 | //
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126 | Start = 0;
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127 | End = 0;
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128 | Total = 0;
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129 |
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130 | //
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131 | // Retrieve the performance counter properties and compute the number of performance
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132 | // counter ticks required to reach the timeout
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133 | //
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134 | Timeout = DivU64x32 (
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135 | MultU64x32 (
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136 | GetPerformanceCounterProperties (&Start, &End),
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137 | PcdGet32 (PcdSpinLockTimeout)
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138 | ),
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139 | 1000000
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140 | );
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141 | Cycle = End - Start;
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142 | if (Cycle < 0) {
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143 | Cycle = -Cycle;
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144 | }
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145 | Cycle++;
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146 |
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147 | while (!AcquireSpinLockOrFail (SpinLock)) {
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148 | CpuPause ();
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149 | Previous = Current;
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150 | Current = GetPerformanceCounter();
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151 | Delta = (INT64) (Current - Previous);
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152 | if (Start > End) {
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153 | Delta = -Delta;
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154 | }
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155 | if (Delta < 0) {
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156 | Delta += Cycle;
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157 | }
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158 | Total += Delta;
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159 | ASSERT (Total < Timeout);
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160 | }
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161 | }
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162 | return SpinLock;
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163 | }
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164 |
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165 | /**
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166 | Attempts to place a spin lock in the acquired state.
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167 |
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168 | This function checks the state of the spin lock specified by SpinLock. If
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169 | SpinLock is in the released state, then this function places SpinLock in the
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170 | acquired state and returns TRUE. Otherwise, FALSE is returned. All state
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171 | transitions of SpinLock must be performed using MP safe mechanisms.
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172 |
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173 | If SpinLock is NULL, then ASSERT().
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174 | If SpinLock was not initialized with InitializeSpinLock(), then ASSERT().
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175 |
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176 | @param SpinLock A pointer to the spin lock to place in the acquired state.
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177 |
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178 | @retval TRUE SpinLock was placed in the acquired state.
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179 | @retval FALSE SpinLock could not be acquired.
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180 |
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181 | **/
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182 | BOOLEAN
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183 | EFIAPI
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184 | AcquireSpinLockOrFail (
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185 | IN OUT SPIN_LOCK *SpinLock
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186 | )
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187 | {
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188 | SPIN_LOCK LockValue;
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189 | VOID *Result;
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190 |
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191 | ASSERT (SpinLock != NULL);
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192 |
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193 | LockValue = *SpinLock;
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194 | ASSERT (LockValue == SPIN_LOCK_ACQUIRED || LockValue == SPIN_LOCK_RELEASED);
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195 |
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196 | _ReadWriteBarrier ();
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197 | Result = InterlockedCompareExchangePointer (
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198 | (VOID**)SpinLock,
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199 | (VOID*)SPIN_LOCK_RELEASED,
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200 | (VOID*)SPIN_LOCK_ACQUIRED
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201 | );
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202 |
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203 | _ReadWriteBarrier ();
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204 | return (BOOLEAN) (Result == (VOID*) SPIN_LOCK_RELEASED);
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205 | }
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206 |
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207 | /**
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208 | Releases a spin lock.
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209 |
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210 | This function places the spin lock specified by SpinLock in the release state
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211 | and returns SpinLock.
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212 |
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213 | If SpinLock is NULL, then ASSERT().
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214 | If SpinLock was not initialized with InitializeSpinLock(), then ASSERT().
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215 |
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216 | @param SpinLock A pointer to the spin lock to release.
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217 |
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218 | @return SpinLock released the lock.
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219 |
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220 | **/
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221 | SPIN_LOCK *
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222 | EFIAPI
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223 | ReleaseSpinLock (
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224 | IN OUT SPIN_LOCK *SpinLock
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225 | )
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226 | {
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227 | SPIN_LOCK LockValue;
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228 |
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229 | ASSERT (SpinLock != NULL);
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230 |
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231 | LockValue = *SpinLock;
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232 | ASSERT (LockValue == SPIN_LOCK_ACQUIRED || LockValue == SPIN_LOCK_RELEASED);
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233 |
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234 | _ReadWriteBarrier ();
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235 | *SpinLock = SPIN_LOCK_RELEASED;
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236 | _ReadWriteBarrier ();
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237 |
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238 | return SpinLock;
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239 | }
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240 |
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241 | /**
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242 | Performs an atomic increment of an 32-bit unsigned integer.
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243 |
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244 | Performs an atomic increment of the 32-bit unsigned integer specified by
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245 | Value and returns the incremented value. The increment operation must be
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246 | performed using MP safe mechanisms.
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247 |
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248 | If Value is NULL, then ASSERT().
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249 |
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250 | @param Value A pointer to the 32-bit value to increment.
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251 |
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252 | @return The incremented value.
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253 |
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254 | **/
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255 | UINT32
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256 | EFIAPI
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257 | InterlockedIncrement (
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258 | IN volatile UINT32 *Value
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259 | )
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260 | {
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261 | ASSERT (Value != NULL);
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262 | return InternalSyncIncrement (Value);
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263 | }
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264 |
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265 | /**
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266 | Performs an atomic decrement of an 32-bit unsigned integer.
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267 |
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268 | Performs an atomic decrement of the 32-bit unsigned integer specified by
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269 | Value and returns the decremented value. The decrement operation must be
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270 | performed using MP safe mechanisms.
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271 |
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272 | If Value is NULL, then ASSERT().
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273 |
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274 | @param Value A pointer to the 32-bit value to decrement.
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275 |
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276 | @return The decremented value.
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277 |
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278 | **/
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279 | UINT32
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280 | EFIAPI
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281 | InterlockedDecrement (
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282 | IN volatile UINT32 *Value
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283 | )
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284 | {
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285 | ASSERT (Value != NULL);
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286 | return InternalSyncDecrement (Value);
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287 | }
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288 |
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289 | /**
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290 | Performs an atomic compare exchange operation on a 16-bit unsigned integer.
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291 |
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292 | Performs an atomic compare exchange operation on the 16-bit unsigned integer
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293 | specified by Value. If Value is equal to CompareValue, then Value is set to
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294 | ExchangeValue and CompareValue is returned. If Value is not equal to CompareValue,
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295 | then Value is returned. The compare exchange operation must be performed using
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296 | MP safe mechanisms.
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297 |
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298 | If Value is NULL, then ASSERT().
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299 |
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300 | @param Value A pointer to the 16-bit value for the compare exchange
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301 | operation.
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302 | @param CompareValue A 16-bit value used in a compare operation.
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303 | @param ExchangeValue A 16-bit value used in an exchange operation.
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304 |
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305 | @return The original *Value before exchange.
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306 |
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307 | **/
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308 | UINT16
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309 | EFIAPI
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310 | InterlockedCompareExchange16 (
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311 | IN OUT volatile UINT16 *Value,
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312 | IN UINT16 CompareValue,
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313 | IN UINT16 ExchangeValue
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314 | )
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315 | {
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316 | ASSERT (Value != NULL);
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317 | return InternalSyncCompareExchange16 (Value, CompareValue, ExchangeValue);
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318 | }
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319 |
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320 | /**
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321 | Performs an atomic compare exchange operation on a 32-bit unsigned integer.
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322 |
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323 | Performs an atomic compare exchange operation on the 32-bit unsigned integer
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324 | specified by Value. If Value is equal to CompareValue, then Value is set to
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325 | ExchangeValue and CompareValue is returned. If Value is not equal to CompareValue,
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326 | then Value is returned. The compare exchange operation must be performed using
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327 | MP safe mechanisms.
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328 |
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329 | If Value is NULL, then ASSERT().
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330 |
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331 | @param Value A pointer to the 32-bit value for the compare exchange
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332 | operation.
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333 | @param CompareValue A 32-bit value used in a compare operation.
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334 | @param ExchangeValue A 32-bit value used in an exchange operation.
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335 |
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336 | @return The original *Value before exchange.
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337 |
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338 | **/
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339 | UINT32
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340 | EFIAPI
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341 | InterlockedCompareExchange32 (
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342 | IN OUT volatile UINT32 *Value,
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343 | IN UINT32 CompareValue,
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344 | IN UINT32 ExchangeValue
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345 | )
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346 | {
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347 | ASSERT (Value != NULL);
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348 | return InternalSyncCompareExchange32 (Value, CompareValue, ExchangeValue);
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349 | }
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350 |
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351 | /**
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352 | Performs an atomic compare exchange operation on a 64-bit unsigned integer.
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353 |
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354 | Performs an atomic compare exchange operation on the 64-bit unsigned integer specified
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355 | by Value. If Value is equal to CompareValue, then Value is set to ExchangeValue and
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356 | CompareValue is returned. If Value is not equal to CompareValue, then Value is returned.
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357 | The compare exchange operation must be performed using MP safe mechanisms.
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358 |
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359 | If Value is NULL, then ASSERT().
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360 |
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361 | @param Value A pointer to the 64-bit value for the compare exchange
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362 | operation.
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363 | @param CompareValue A 64-bit value used in a compare operation.
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364 | @param ExchangeValue A 64-bit value used in an exchange operation.
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365 |
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366 | @return The original *Value before exchange.
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367 |
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368 | **/
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369 | UINT64
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370 | EFIAPI
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371 | InterlockedCompareExchange64 (
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372 | IN OUT volatile UINT64 *Value,
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373 | IN UINT64 CompareValue,
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374 | IN UINT64 ExchangeValue
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375 | )
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376 | {
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377 | ASSERT (Value != NULL);
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378 | return InternalSyncCompareExchange64 (Value, CompareValue, ExchangeValue);
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379 | }
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380 |
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381 | /**
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382 | Performs an atomic compare exchange operation on a pointer value.
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383 |
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384 | Performs an atomic compare exchange operation on the pointer value specified
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385 | by Value. If Value is equal to CompareValue, then Value is set to
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386 | ExchangeValue and CompareValue is returned. If Value is not equal to
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387 | CompareValue, then Value is returned. The compare exchange operation must be
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388 | performed using MP safe mechanisms.
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389 |
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390 | If Value is NULL, then ASSERT().
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391 |
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392 | @param Value A pointer to the pointer value for the compare exchange
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393 | operation.
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394 | @param CompareValue A pointer value used in a compare operation.
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395 | @param ExchangeValue A pointer value used in an exchange operation.
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396 |
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397 | @return The original *Value before exchange.
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398 | **/
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399 | VOID *
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400 | EFIAPI
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401 | InterlockedCompareExchangePointer (
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402 | IN OUT VOID * volatile *Value,
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403 | IN VOID *CompareValue,
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404 | IN VOID *ExchangeValue
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405 | )
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406 | {
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407 | UINT8 SizeOfValue;
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408 |
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409 | SizeOfValue = (UINT8) sizeof (*Value);
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410 |
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411 | switch (SizeOfValue) {
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412 | case sizeof (UINT32):
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413 | return (VOID*)(UINTN)InterlockedCompareExchange32 (
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414 | (volatile UINT32*)Value,
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415 | (UINT32)(UINTN)CompareValue,
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416 | (UINT32)(UINTN)ExchangeValue
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417 | );
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418 | case sizeof (UINT64):
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419 | return (VOID*)(UINTN)InterlockedCompareExchange64 (
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420 | (volatile UINT64*)Value,
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421 | (UINT64)(UINTN)CompareValue,
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422 | (UINT64)(UINTN)ExchangeValue
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423 | );
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424 | default:
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425 | ASSERT (FALSE);
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426 | return NULL;
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427 | }
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428 | }
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