ARM Cortex R4F - Manual (Page 295)

Debug
ARM DDI 0363E Copyright © 2009 ARM Limited. All rights reserved. 11-26
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11.4.14 Watchpoint Value Registers
Each WVR is associated with a Watchpoint Control Register (WCR). WCRy is the
corresponding register for WVRy.
A pair of watchpoint registers, WVRy and WCRy, is called a Watchpoint Register Pair (WRP).
WVR0-7 are paired with WCR0-7 to make WRP0-7.
The watchpoint value contained in the WVR always corresponds to a data address and can be
set either on:
•
a data address
• a data address and context ID pair.
For a data address and context ID pair, a WRP and a BRP with context ID comparison capability
must be linked. A debug event is generated when both the data address and the context ID pair
match simultaneously. Table 11-19 shows the bit field definitions for the Watchpoint Value
Registers.
11.4.15 Watchpoint Control Registers
The WCRs contain the necessary control bits for setting:
•
watchpoints
• linked watchpoints.
Figure 11-11 on page 11-27 shows the bit arrangement of the Watchpoint Control Registers.
b011 The corresponding BVR[31:0] is compared against CP15 Context ID Register, c13. This BRP links
another BRP (of the BCR[21:20]=b01 type), or WRP (with WCR[20]=b1). They generate a breakpoint
or watchpoint debug event on a joint instruction address or data address and context ID match. For this
BRP, BCR[8:5] must be set to b1111, BCR[15:14] must be set to b00, and BCR[2:1] must be set to b11.
Otherwise it is Unpredictable whether a breakpoint debug event is generated.
b100 The corresponding BVR[31:2] and BCR[8:5] are compared against the instruction address bus and the
state of the processor against this BCR. It generates a breakpoint debug event on a joint instruction
address mismatch and state match.
b101 The corresponding BVR[31:2] and BCR[8:5] are compared against the instruction address bus and the
state of the processor against this BCR. This BRP is linked with the one indicated by BCR[19:16] linked
BRP field. It generates a breakpoint debug event on a joint instruction address mismatch, state and
context ID match.
b11x Reserved. The behavior is Unpredictable.
Table 11-18 Meaning of BVR bits [22:20] (continued)
BVR[22:20] Meaning
Table 11-19 Watchpoint Value Registers functions
Bits Description
[31:2] Watchpoint address.
[1:0] Reserved. Do not modify on writes. On reads, the value returns zero.