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215 lines
6.2 KiB
215 lines
6.2 KiB
// Implementation of synchronization functions for ARM architecture
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//
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// Copyright (c) 2012-2015, ARM Limited. All rights reserved.
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// Copyright (c) 2015, Linaro Limited. All rights reserved.
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//
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// This program and the accompanying materials
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// are licensed and made available under the terms and conditions of the BSD License
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// which accompanies this distribution. The full text of the license may be found at
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// http://opensource.org/licenses/bsd-license.php
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//
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// THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
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// WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
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//
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//
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EXPORT InternalSyncCompareExchange16
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EXPORT InternalSyncCompareExchange32
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EXPORT InternalSyncCompareExchange64
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EXPORT InternalSyncIncrement
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EXPORT InternalSyncDecrement
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AREA ArmSynchronization, CODE, READONLY
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/**
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Performs an atomic compare exchange operation on a 16-bit unsigned integer.
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Performs an atomic compare exchange operation on the 16-bit unsigned integer
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specified by Value. If Value is equal to CompareValue, then Value is set to
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ExchangeValue and CompareValue is returned. If Value is not equal to CompareValue,
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then Value is returned. The compare exchange operation must be performed using
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MP safe mechanisms.
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@param Value A pointer to the 16-bit value for the compare exchange
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operation.
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@param CompareValue 16-bit value used in compare operation.
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@param ExchangeValue 16-bit value used in exchange operation.
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@return The original *Value before exchange.
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**/
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//UINT16
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//EFIAPI
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//InternalSyncCompareExchange16 (
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// IN volatile UINT16 *Value,
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// IN UINT16 CompareValue,
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// IN UINT16 ExchangeValue
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// )
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InternalSyncCompareExchange16
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dmb
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InternalSyncCompareExchange16Again
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ldrexh r3, [r0]
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cmp r3, r1
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bne InternalSyncCompareExchange16Fail
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InternalSyncCompareExchange16Exchange
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strexh ip, r2, [r0]
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cmp ip, #0
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bne InternalSyncCompareExchange16Again
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InternalSyncCompareExchange16Fail
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dmb
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mov r0, r3
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bx lr
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/**
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Performs an atomic compare exchange operation on a 32-bit unsigned integer.
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Performs an atomic compare exchange operation on the 32-bit unsigned integer
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specified by Value. If Value is equal to CompareValue, then Value is set to
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ExchangeValue and CompareValue is returned. If Value is not equal to CompareValue,
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then Value is returned. The compare exchange operation must be performed using
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MP safe mechanisms.
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@param Value A pointer to the 32-bit value for the compare exchange
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operation.
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@param CompareValue 32-bit value used in compare operation.
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@param ExchangeValue 32-bit value used in exchange operation.
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@return The original *Value before exchange.
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**/
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//UINT32
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//EFIAPI
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//InternalSyncCompareExchange32 (
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// IN volatile UINT32 *Value,
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// IN UINT32 CompareValue,
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// IN UINT32 ExchangeValue
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// )
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InternalSyncCompareExchange32
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dmb
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InternalSyncCompareExchange32Again
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ldrex r3, [r0]
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cmp r3, r1
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bne InternalSyncCompareExchange32Fail
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InternalSyncCompareExchange32Exchange
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strex ip, r2, [r0]
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cmp ip, #0
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bne InternalSyncCompareExchange32Again
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InternalSyncCompareExchange32Fail
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dmb
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mov r0, r3
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bx lr
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/**
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Performs an atomic compare exchange operation on a 64-bit unsigned integer.
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Performs an atomic compare exchange operation on the 64-bit unsigned integer specified
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by Value. If Value is equal to CompareValue, then Value is set to ExchangeValue and
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CompareValue is returned. If Value is not equal to CompareValue, then Value is returned.
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The compare exchange operation must be performed using MP safe mechanisms.
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@param Value A pointer to the 64-bit value for the compare exchange
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operation.
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@param CompareValue 64-bit value used in compare operation.
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@param ExchangeValue 64-bit value used in exchange operation.
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@return The original *Value before exchange.
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**/
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//UINT64
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//EFIAPI
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//InternalSyncCompareExchange64 (
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// IN volatile UINT64 *Value, // r0
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// IN UINT64 CompareValue, // r2-r3
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// IN UINT64 ExchangeValue // stack
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// )
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InternalSyncCompareExchange64
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push { r4-r7 }
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ldrd r4, r5, [sp, #16]
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dmb
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InternalSyncCompareExchange64Again
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ldrexd r6, r7, [r0]
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cmp r6, r2
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cmpeq r7, r3
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bne InternalSyncCompareExchange64Fail
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InternalSyncCompareExchange64Exchange
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strexd ip, r4, r5, [r0]
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cmp ip, #0
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bne InternalSyncCompareExchange64Again
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InternalSyncCompareExchange64Fail
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dmb
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mov r0, r6
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mov r1, r7
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pop { r4-r7 }
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bx lr
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/**
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Performs an atomic increment of an 32-bit unsigned integer.
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Performs an atomic increment of the 32-bit unsigned integer specified by
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Value and returns the incremented value. The increment operation must be
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performed using MP safe mechanisms. The state of the return value is not
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guaranteed to be MP safe.
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@param Value A pointer to the 32-bit value to increment.
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@return The incremented value.
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**/
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//UINT32
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//EFIAPI
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//InternalSyncIncrement (
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// IN volatile UINT32 *Value
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// )
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InternalSyncIncrement
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dmb
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TryInternalSyncIncrement
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ldrex r1, [r0]
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add r1, r1, #1
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strex r2, r1, [r0]
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cmp r2, #0
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bne TryInternalSyncIncrement
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dmb
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mov r0, r1
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bx lr
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/**
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Performs an atomic decrement of an 32-bit unsigned integer.
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Performs an atomic decrement of the 32-bit unsigned integer specified by
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Value and returns the decrement value. The decrement operation must be
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performed using MP safe mechanisms. The state of the return value is not
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guaranteed to be MP safe.
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@param Value A pointer to the 32-bit value to decrement.
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@return The decrement value.
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**/
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//UINT32
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//EFIAPI
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//InternalSyncDecrement (
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// IN volatile UINT32 *Value
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// )
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InternalSyncDecrement
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dmb
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TryInternalSyncDecrement
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ldrex r1, [r0]
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sub r1, r1, #1
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strex r2, r1, [r0]
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cmp r2, #0
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bne TryInternalSyncDecrement
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dmb
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mov r0, r1
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bx lr
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END
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