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// Implementation of synchronization functions for ARM architecture (AArch64)
//
// Copyright (c) 2012-2015, ARM Limited. All rights reserved.
// Copyright (c) 2015, Linaro Limited. All rights reserved.
//
// SPDX-License-Identifier: BSD-2-Clause-Patent
//
//
.text
.align 3
GCC_ASM_EXPORT(InternalSyncCompareExchange16)
GCC_ASM_EXPORT(InternalSyncCompareExchange32)
GCC_ASM_EXPORT(InternalSyncCompareExchange64)
GCC_ASM_EXPORT(InternalSyncIncrement)
GCC_ASM_EXPORT(InternalSyncDecrement)
/**
Performs an atomic compare exchange operation on a 16-bit unsigned integer.
Performs an atomic compare exchange operation on the 16-bit unsigned integer
specified by Value. If Value is equal to CompareValue, then Value is set to
ExchangeValue and CompareValue is returned. If Value is not equal to CompareValue,
then Value is returned. The compare exchange operation must be performed using
MP safe mechanisms.
@param Value A pointer to the 16-bit value for the compare exchange
operation.
@param CompareValue 16-bit value used in compare operation.
@param ExchangeValue 16-bit value used in exchange operation.
@return The original *Value before exchange.
**/
//UINT16
//EFIAPI
//InternalSyncCompareExchange16 (
// IN volatile UINT16 *Value,
// IN UINT16 CompareValue,
// IN UINT16 ExchangeValue
// )
ASM_PFX(InternalSyncCompareExchange16):
AARCH64_BTI(c)
uxth w1, w1
uxth w2, w2
dmb sy
InternalSyncCompareExchange16Again:
ldxrh w3, [x0]
cmp w3, w1
bne InternalSyncCompareExchange16Fail
InternalSyncCompareExchange16Exchange:
stxrh w4, w2, [x0]
cbnz w4, InternalSyncCompareExchange16Again
InternalSyncCompareExchange16Fail:
dmb sy
mov w0, w3
ret
/**
Performs an atomic compare exchange operation on a 32-bit unsigned integer.
Performs an atomic compare exchange operation on the 32-bit unsigned integer
specified by Value. If Value is equal to CompareValue, then Value is set to
ExchangeValue and CompareValue is returned. If Value is not equal to CompareValue,
then Value is returned. The compare exchange operation must be performed using
MP safe mechanisms.
@param Value A pointer to the 32-bit value for the compare exchange
operation.
@param CompareValue 32-bit value used in compare operation.
@param ExchangeValue 32-bit value used in exchange operation.
@return The original *Value before exchange.
**/
//UINT32
//EFIAPI
//InternalSyncCompareExchange32 (
// IN volatile UINT32 *Value,
// IN UINT32 CompareValue,
// IN UINT32 ExchangeValue
// )
ASM_PFX(InternalSyncCompareExchange32):
AARCH64_BTI(c)
dmb sy
InternalSyncCompareExchange32Again:
ldxr w3, [x0]
cmp w3, w1
bne InternalSyncCompareExchange32Fail
InternalSyncCompareExchange32Exchange:
stxr w4, w2, [x0]
cbnz w4, InternalSyncCompareExchange32Again
InternalSyncCompareExchange32Fail:
dmb sy
mov w0, w3
ret
/**
Performs an atomic compare exchange operation on a 64-bit unsigned integer.
Performs an atomic compare exchange operation on the 64-bit unsigned integer specified
by Value. If Value is equal to CompareValue, then Value is set to ExchangeValue and
CompareValue is returned. If Value is not equal to CompareValue, then Value is returned.
The compare exchange operation must be performed using MP safe mechanisms.
@param Value A pointer to the 64-bit value for the compare exchange
operation.
@param CompareValue 64-bit value used in compare operation.
@param ExchangeValue 64-bit value used in exchange operation.
@return The original *Value before exchange.
**/
//UINT64
//EFIAPI
//InternalSyncCompareExchange64 (
// IN volatile UINT64 *Value,
// IN UINT64 CompareValue,
// IN UINT64 ExchangeValue
// )
ASM_PFX(InternalSyncCompareExchange64):
AARCH64_BTI(c)
dmb sy
InternalSyncCompareExchange64Again:
ldxr x3, [x0]
cmp x3, x1
bne InternalSyncCompareExchange64Fail
InternalSyncCompareExchange64Exchange:
stxr w4, x2, [x0]
cbnz w4, InternalSyncCompareExchange64Again
InternalSyncCompareExchange64Fail:
dmb sy
mov x0, x3
ret
/**
Performs an atomic increment of an 32-bit unsigned integer.
Performs an atomic increment of the 32-bit unsigned integer specified by
Value and returns the incremented value. The increment operation must be
performed using MP safe mechanisms. The state of the return value is not
guaranteed to be MP safe.
@param Value A pointer to the 32-bit value to increment.
@return The incremented value.
**/
//UINT32
//EFIAPI
//InternalSyncIncrement (
// IN volatile UINT32 *Value
// )
ASM_PFX(InternalSyncIncrement):
AARCH64_BTI(c)
dmb sy
TryInternalSyncIncrement:
ldxr w1, [x0]
add w1, w1, #1
stxr w2, w1, [x0]
cbnz w2, TryInternalSyncIncrement
mov w0, w1
dmb sy
ret
/**
Performs an atomic decrement of an 32-bit unsigned integer.
Performs an atomic decrement of the 32-bit unsigned integer specified by
Value and returns the decrement value. The decrement operation must be
performed using MP safe mechanisms. The state of the return value is not
guaranteed to be MP safe.
@param Value A pointer to the 32-bit value to decrement.
@return The decrement value.
**/
//UINT32
//EFIAPI
//InternalSyncDecrement (
// IN volatile UINT32 *Value
// )
ASM_PFX(InternalSyncDecrement):
AARCH64_BTI(c)
dmb sy
TryInternalSyncDecrement:
ldxr w1, [x0]
sub w1, w1, #1
stxr w2, w1, [x0]
cbnz w2, TryInternalSyncDecrement
mov w0, w1
dmb sy
ret
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