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Section 11 User Break Controller (UBC)
Rev. 4.00 Sep. 14, 2005 Page 267 of 982
REJ09B0023-0400
4. When a user break and another exception occur at the same instruction, which has higher
priority is determined according to the priority levels defined in table 9.1 in section 9,
Exception Handling. If an exception with higher priority occurs, the user break is not
generated.
Pre-execution break has the highest priority.
When a post-execution break or data access break occurs simultaneously with a re-
execution-type exception (including pre-execution break) that has higher priority, the re-
execution-type exception is accepted, and the condition match flag is not set (see the
exception in the following note). The break will occur and the condition match flag will be
set only after the exception source of the re-execution-type exception has been cleared by
the exception handling routine and re-execution of the same instruction has ended.
When a post-execution break or data access break occurs simultaneously with a
completion-type exception (TRAPA) that has higher priority, though a break does not
occur, the condition match flag is set.
5. Note the following exception for the above note.
If a post-execution break or data access break is satisfied by an instruction that generates a
CPU address error by data access, the CPU address error is given priority to the break. Note
that the UBC condition match flag is set in this case.
6. Note the following when a break occurs in a delay slot.
If a pre-execution break is set at the delay slot instruction of the RTE instruction, the break
does not occur until the branch destination of the RTE instruction.
7. User breaks are disabled during USB module standby mode. Do not read from or write to the
UBC registers during USB module standby mode; the values are not guaranteed.
8. When the repeat loop of the DSP extended function is used, even though a break condition is
satisfied during execution of the entire repeat loop or several instructions in the repeat loop, the
break may be held. For details, see section 9, Exception Handling.