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

0b01 watchpoint generated on match only in Non-secure state
0b10 watchpoint generated on match only in Secure state
0b11 Reserved.
Debug Registers Reference
For more information about watchpoint matching when this field is set to a value other than
0b00, see About security state control on page C10-66.
Bits [15:14], when the Security Extensions are not implemented
Reserved, UNK/SBZP.
Bit [12:9], v6 Debug and v6.1 Debug
Reserved, UNK/SBZP.
Byte address select, bits [12:5] or bits [8:5]
The width of this field can depend on the ARM Debug architecture version:
v6 Debug and v6.1 Debug
The Byte address select field is always 4 bits, DBGWCR[8:5]
v7 Debug
It is IMPLEMENTATION DEFINED whether a 4-bit or an 8-bit Byte address select
field is implemented:
an 8-bit Byte address select field is DBGWCR[12:5]
if a 4-bit Byte address select field is implemented then the Byte address
select field is DBGWCR[8:5] and DBGWCR[12:9] is RAZ/WI.
DBGWVRs are programmed with word-aligned addresses. This field enables the
watchpoint to hits only if certain byte addresses are accessed. The watchpoint hits if an
access hits any byte being watched, even if:
the access size is larger than the size of the region being watched
the access is unaligned, and the base address of the access is not in the same word of
memory as the address in the DBGWVR.
For details of the use of this field see Byte address masking behavior on DVA match on
page C10-65.
If the Address range mask field is implemented and programmed to a value other than
0b00000, no mask, then this field must be programmed to:
0b1111, if a 4-bit Byte address select field is implemented.
0b11111111, an 8-bit Byte address select field is implemented.
If this is not done, the generation of Watchpoint debug events is UNPREDICTABLE.
Load/store access control, bits [4:3]
This field enables watchpoint matching conditional on the type of access being made.
Possible values of this field are:
0b00 Reserved.
0b01 Match on any load, Load-Exclusive, or swap.
ARM DDI 0406B Copyright © 1996-1998, 2000, 2004-2008 ARM Limited. All rights reserved. C10-63