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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
;
;
EXPORT InternalSyncCompareExchange16
EXPORT InternalSyncCompareExchange32
EXPORT InternalSyncCompareExchange64
EXPORT InternalSyncIncrement
EXPORT InternalSyncDecrement
AREA BaseSynchronizationLib_LowLevel, CODE, READONLY
;/**
; 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
; )
InternalSyncCompareExchange16
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
; )
InternalSyncCompareExchange32
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
; )
InternalSyncCompareExchange64
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
; )
InternalSyncIncrement
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
; )
InternalSyncDecrement
dmb sy
TryInternalSyncDecrement
ldxr w1, [x0]
sub w1, w1, #1
stxr w2, w1, [x0]
cbnz w2, TryInternalSyncDecrement
mov w0, w1
dmb sy
ret
END
|
