ARM r1p3, R4, R4F 11.6 Debug events

Debug

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11.6 Debug events

A processor responds to a debug event in one of the following ways:

• ignores the debug event

• takes a debug exception

• enters debug state.

This section describes:

•Software debug event

•Halting debug event on page 11-40.

•Behavior of the processor on debug events on page11-40

•Debug event priority on page11-40

•Watchpoint debug events on page11-40.

11.6.1 Software debug event

A software debug event is any of the following:

• A watchpoint debug event. This occurs when:

— The data address for a load or store matches the watchpoint value.

— All the conditions of the WCR match.

— The watchpoint is enabled.

— The linked context ID-holding BRP, if any, is enabled and its value matches the

context ID in CP15 c13. See Chapter 4 System Control Coprocessor.

— The instruction that initiated the memory access is committed for execution.

Watchpoint debug events are only generated if the instruction passes its condition code.

• A breakpoint debug event. This occurs when:

— An instruction was fetched and the instruction address or the CP15 Con text ID

— At the same time the instruction was fetched, all the conditions of th e BCR for

unlinked context ID breakpoint generation matched the I-side control signals.

— The breakpoint is enabled.

— The instruction is committed for execution. These debug events are generated

whether the instruction passes or fails its condition code.

• A BKPT debug event. This occurs when a

BKPT

instruction is committed for execution.

BKPT

is an unconditional instruction.

• A vector catch debug event. This occurs when:

— An instruction was prefetched and the address matched a vector location address.

This includes any kind of prefetch, not only the ones because of exception entry.

— At the same time the instruction wa s fetched, the corresponding bit of the VCR was

set, that is, the vector catch is enabled.

— The instruction is committed for execution. These debug events are generated

whether the instruction passes or fails its condition code.