Nios II Classic Processor Reference Guide

ID 683620
Date 10/28/2016
Document Table of Contents Return Address Considerations

The return address requires some consideration when returning from exception processing routines. After an exception occurs, ea contains the address of the instruction following the point where the exception occurred.

When returning from instruction-related exceptions, execution must resume from the instruction following the instruction where the exception occurred. Therefore, ea contains the correct return address.

On the other hand, hardware interrupt exceptions must resume execution from the interrupted instruction itself. In this case, the exception handler must subtract 4 from ea to point to the interrupted instruction.