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10.5.4. Watchpoint Control Registers

The WCRs contain the necessary control bits for setting:

  • watchpoints

  • linked watchpoints.

Figure 10.4 shows the WCRs bit assignments.

Figure 10.4. WCR Register bit assignments

Figure 10.4. WCR Register bit assignments

Table 10.8 shows the WCRs bit assignments.

Table 10.8. WCR Register bit assignments
BitsNameDescription

[31:29]

-RAZ on reads, SBZP on writes.

[28:24]

Watchpoint address mask

Watchpoint address mask.

[23:21]

-RAZ on reads, SBZP on writes.

[20]

E

Enable linking bit:

0

Linking disabled.

1

Linking enabled.

When this bit is set, this watchpoint is linked with the context ID holding BRP selected by the linked BRP field.

[19:16]

Linked BRP

Linked BRP number. The binary number encoded here indicates a context ID holding BRP to link this WRP with. If this WRP is linked to a BRP that is not configured for linked context ID matching, it is unpredictable whether a watchpoint debug event is generated.

[15:14]

Secure state access control

Secure state access control. This field enables the watchpoint to be conditioned on the security state of the processor:

b00

Watchpoint matches in both Secure and Non-secure state.

b01

Watchpoint only matches in Non-secure state.

b10

Watchpoint only matches in Secure state.

b11

Reserved.

[13]

-RAZ on reads, SBZP on writes.

[12:9]

-RAZ/WI.
[8:5]Byte address select

Byte address select. The WVR is programmed with word-aligned address. You can use this field to program the watchpoint so it only hits if certain byte addresses are accessed.

[4:3]

L/S

Load/store access. The watchpoint can be conditioned to the type of access being done:

b00

Reserved.

b01

Load, load exclusive, or swap.

b10

Store, store exclusive or swap.

b11

Either.

SWP and SWPB trigger a watchpoint on b01, b10, or b11. A load exclusive instruction triggers a watchpoint on b01 or b11. A store exclusive instruction triggers a watchpoint on b10 or b11 only if it passes the local monitor within the processor.[a]

[2:1]

SP

Privileged access control. The watchpoint can be conditioned to the privilege of the access being done:

b00

Reserved.

b01

Privileged, match if the processor does a privileged access to memory.

b10

User, match only on nonprivileged accesses.

b11

Either, match all accesses.

Note

For all cases, the match refers to the privilege of the access, not the mode of the processor.

[0]

W

Watchpoint enable:

0

Watchpoint disabled, reset value.

1

Watchpoint enabled.

[a] A store exclusive can generate an MMU fault or cause the processor to take a data watchpoint exception regardless of the state of the local monitor.


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