AN 977: Nios® V Processor Custom Instruction

ID 773194
Date 4/14/2023
Document Table of Contents

1.3. Implementing Custom Instruction Software

The Nios® V processor custom instruction software interface outlines the custom instruction details for the software developer.

For each custom instruction, the Board Support Package Editor generates a macro in the system header file, system.h and an accompanying GDB debug mnemonics file, custom_instruction_debug.xml. You can use the macro directly in your C or C++ application code. You do not need to program the assembly code to access the custom instructions. A software can also invoke custom instructions in the assembly language. The GDB debug mnemonics file can be used with the Ashling* RiscFree* IDE for Intel® FPGAs to provide debug mnemonics for user defined custom instruction encodings.