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UM10360_0
© NXP B.V. 2009. All rights reserved.
User manual
Rev. 00.06 — 5 June 2009
645 of 808
NXP Semiconductors
UM10360
Chapter 34: Appendix: Cortex-M3 User Guide
2.4.9 CLREX
Clear Exclusive.
2.4.9.1
Syntax
CLREX{
cond
}
where:
cond i
s an optional condition code, see
Section 34–2.3.7 “Conditional execution”
.
2.4.9.2
Operation
Use
CLREX
to make the next
STREX
,
STREXB
, or
STREXH
instruction write 1 to its destination
register and fail to perform the store. It is useful in exception handler code to force the
failure of the store exclusive if the exception occurs between a load exclusive instruction
and the matching store exclusive instruction in a synchronization operation.
See
Section 35–1.2.7 “Synchronization primitives”
for more information.
2.4.9.3
Condition flags
These instructions do not change the flags.
2.4.9.4
Examples
CLREX