Nios® II Processor Reference Guide

ID 683836
Date 8/28/2023
Document Table of Contents Understanding Register Usage

The bstatus control register and general-purpose registers bt (r25) and ba (r30) in the normal register set are reserved for debugging. Code is not prevented from writing to these registers, but debug code might overwrite the values. The break handler can use bt (r25) to help save additional registers.