Debug
ARM DDI 0388I
Copyright © 2008-2012 ARM. All rights reserved.
10-15
ID073015
Non-Confidential
10.7
Debug events
A debug event can be either:
•
a software debug event
•
a halting debug event.
A processor responds to a debug event in one of the following ways:
•
ignores the debug event
•
takes a debug exception
•
enters debug state.
This section describes debug events in:
•
•
10.7.1
Watchpoints
A watchpoint event is always synchronous. It has the same behavior as a synchronous data
abort. The method of debug entry, DBGDSCR[5:2], never has the value b0010.
If a synchronous abort occurs on a watchpointed access, the synchronous abort takes priority
over the watchpoint.
If the abort is asynchronous and cannot be associated with the access, the exception that is taken
is
UNPREDICTABLE
.
Cache maintenance operations do not generate watchpoint events.
10.7.2
Asynchronous aborts
The Cortex-A9 processor ensures that all possible outstanding asynchronous data aborts are
recognized prior to entry to debug state.