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

Debug Registers Reference
C10.5 Software debug event registers
This section contains the following subsections:
Breakpoint Value Registers (DBGBVR)
Breakpoint Control Registers (DBGBCR) on page C10-49
Watchpoint Value Registers (DBGWVR) on page C10-60
Watchpoint Control Registers (DBGWCR) on page C10-61
Vector Catch Register (DBGVCR) on page C10-67.
In addition, when the OS Save and Restore mechanism is implemented, the Event Catch Register can be
used to enable generation of a debug event when the OS Lock is unlocked, see Event Catch Register
(DBGECR) on page C10-78.
C10.5.1 Breakpoint Value Registers (DBGBVR)
A Breakpoint Value Register, DBGBVR, holds a value for use in breakpoint matching. The value is either
an Instruction Virtual Address (IVA) or a Context ID. Each DBGBVR is associated with a DBGBCR to form
a Breakpoint Register Pair (BRP). DBGBVRn is associated with DBGBCRn to form BRPn, where n takes
the values from 0 to 15. A debug event is generated when an instruction that matches the BRP is committed
for execution. For more information, see Breakpoint debug events on page C3-5.
A breakpoint can be set on any one of:
an IVA match or mismatch
a Context ID match
an IVA match or mismatch occurring with a Context ID match.
For the third case:
two BRPs must be linked, see Breakpoint Control Registers (DBGBCR) on page C10-49.
a debug event is generated when, on the same instruction, both:
— the IVA matches or mismatches, as required
— the Context ID matches.
See Memory addresses on page C3-23 for a definition of the IVA used to program a DBGBVR.
Note
Some BRPs might not support Context ID comparison. For more information, see the description of the
DBGDIDR.CTX_CMPs field in Debug ID Register (DBGDIDR) on page C10-3.
The DBGBVRs are:
debug registers 64-79, at offsets 0x100-0x13C
read/write registers
when the Security Extensions are implemented, Common registers.
C10-48 Copyright © 1996-1998, 2000, 2004-2008 ARM Limited. All rights reserved. ARM DDI 0406B