4.2.3
Acceptance of Exceptions
Processor resets and interrupts are asynchronous events unrelated to the instruction stream. All
exception events are prioritized to establish an acceptance order whenever two or more exception
events occur simultaneously.
All general exception events occur in a relative order in the execution sequence of an instruction
(i.e. execution order), but are handled at priority level 2 in instruction-stream order (i.e. program
order), where an exception detected in a preceding instruction is accepted prior to an exception
detected in a subsequent instruction.
Three general exception events (reserved instruction code exception, unconditional trap, and slot
illegal instruction exception) are detected in the decode stage (ID stage) of different instructions
and are mutually exclusive events in the instruction pipeline. They have the same execution
priority. Figure 4.2 shows the order of general exception acceptance.
Rev. 5.00, 09/03, page 88 of 760
RENESAS [ RENESAS TECHNOLOGY CORP ]
