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ARM DDI 0301H
ID012310
4.
Write the context ID to the BVRb register.
5.
Write to the BCRb with its fields set as follows:
•
BCRb[22:21] meaning of BVR bit set to b01, to indicate that the value loaded into
BVRb is to be compared against the CP15 context ID register 13
•
BCRb[20] enable linking bit, set
•
BCR [15:14] Secure access set to b00.
•
BCRb[8:5] byte address select set to b1111
•
BCRb[2:1] supervisor access set to b11
•
BCRb[0] enable breakpoint bit set.
6.
Write to the BCRa with its fields set as follows:
•
BCRa[22:21] meaning of BVR bit set to b00 or b10, to indicate that the value loaded
into BVRa is to be compared against the IMVA bus as a match or mismatch
•
BCRa[20] enable linking bit set, to link this BRP with the one indicated by
BCRa[19:16], BRPb in this example
•
BCR [15:14] Secure access as required.
•
binary representation of b into BCR[9:6] linked BRP field
•
BCRa[8:5] byte address select field as required
•
BCRa[2:1] supervisor access field as required
•
BCRa[0] enable breakpoint set.
Setting a simple watchpoint
You can set a simple watchpoint as follows:
1.
Read the WCR.
2.
Clear the WCR[0] enable watchpoint bit in the read word and write it back to the WCR.
Now the watchpoint is disabled.
3.
Write the DMVA to the WVR register.
4.
Write to the WCR with its fields set as follows:
•
WCR[20] enable linking bit cleared, to indicate that this watchpoint is not to be
linked
•
WCR byte address select, load/store access, Secure access field, and supervisor
access fields as required
•
WCR[0] enable watchpoint bit set.
Note
Any WVR can be compared against the DMVA bus.
Setting a linked watchpoint
In the following sequence b is any of the BRPs with context ID comparison capability. You can
use any of the WRPs. You can link WRPs and contextID-holding BRPs as follows:
1.
Read the WCR and BCRb.
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