15.5.2. Exception return

The ETM explicitly indicates return from an exception in the trace stream. This is because exception return functionality is encoded in a data-dependent manner, and an exception return behaves differently from a simple branch.

The packet encoding indicates a return from an exception. Figure 15.2 shows this.

Figure 15.2. Return from exception packet encoding

If a new, higher priority exception pre-empts the stack pop, the branch to the exception handler must indicate that the last instruction was cancelled. This indicates that the return from exception packet was cancelled, but the return from exception instruction was not cancelled. If the return from exception packet is present, then this means that the previous instruction did complete.

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