ARM Architecture Reference Manual ARMv7-A and ARMv7-R edition

Table A3-7 shows the effect of the operations shown in Figure A3-3 on page A3-18.
Initial
state a Operation b Effect
Open CLREX(n),
CLREX(!n)
Application Level Memory Model
Table A3-7 Effect of load/store operations on global monitor for processor(n)
Final
state a
None Open
StoreExcl(x,n) Does not update memory, returns status 1 Open
LoadExcl(x,!n) Loads value from memory, no effect on tag address for processor(n) Open
StoreExcl(x,!n) Depends on state machine and tag address for processor issuing
STREX c
Store(x,n),
Store(x,!n)
ARM DDI 0406B Copyright © 1996-1998, 2000, 2004-2008 ARM Limited. All rights reserved. A3-19
Open
Updates memory, no effect on monitor Open
LoadExcl(x,n) Loads value from memory, tags address x Exclusive
Exclusive LoadExcl(x,n) Loads value from memory, tags address x Exclusive
CLREX(n) None. Effect on the final state is IMPLEMENTATION DEFINED.
Exclusive e
Open e
CLREX(!n) None Exclusive
StoreExcl(t,!n)
Updates memory, returns status 0 c Open
Does not update memory, returns status 1 c Exclusive
StoreExcl(t,n) Updates memory, returns status 0 d
StoreExcl(!t,n)
Updates memory, returns status 0 e
Does not update memory, returns status 1 e
StoreExcl(!t,!n) Depends on state machine and tag address for processor issuing
STREX
Open
Exclusive
Open
Exclusive
Open
Exclusive
Exclusive