A breakpoint, BKPT, instruction operates as though the instruction causes a prefetch abort. A breakpoint instruction does not cause the processor to take the prefetch abort exception until the instruction reaches the Execute stage of the pipeline. If the processor does not execute the instruction, for example because a branch occurs while it is in the pipeline, the breakpoint does not take place.

After dealing with the breakpoint, the handler executes the following instruction irrespective of the processor operating state:

SUBS PC,R14_abt,#4

This action restores both the PC and the CPSR, and retries the breakpointed instruction.