Nios® V Processor Reference Manual

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ID 683632
Date 6/30/2022
Public

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Document Table of Contents
Document Table of Contents x
1. About this Document 2. Nios® V/m Processor 3. Nios V Processor Reference Manual Archives 4. Document Revision History for the Nios® V Processor Reference Manual
1. About this Document x
1.1. Overview
2. Nios® V/m Processor x
2.1. Processor Performance Benchmarks 2.2. Processor Pipeline 2.3. Processor Architecture 2.4. Programming Model 2.5. Core Implementation
2.3. Processor Architecture x
2.3.1. General Purpose Register File 2.3.2. Arithmetic Logic Unit 2.3.3. Reset and Debug Signals 2.3.4. Control and Status Registers 2.3.5. Exception Controller 2.3.6. Interrupt Controller 2.3.7. Memory and I/O Organization 2.3.8. RISC-V based Debug Module
2.3.6. Interrupt Controller x
2.3.6.1. Timer and Software Interrupt Module
2.3.7. Memory and I/O Organization x
2.3.7.1. Instruction and Data Buses
2.3.7.1. Instruction and Data Buses x
2.3.7.1.1. Instruction Manager Port 2.3.7.1.2. Data Manager Port 2.3.7.1.3. Address Map
2.3.8. RISC-V based Debug Module x
2.3.8.1. Debug Mode 2.3.8.2. Halt from Debug Module 2.3.8.3. Debug Implementation 2.3.8.4. Abstract Commands in Debug Mode 2.3.8.5. Hardware/Software Interface
2.4. Programming Model x
2.4.1. Privilege Levels 2.4.2. Control and Status Registers (CSR) Mapping
2.4.1. Privilege Levels x
2.4.1.1. Machine Mode (M-mode) 2.4.1.2. Debug Mode (D-mode)
2.4.2. Control and Status Registers (CSR) Mapping x
2.4.2.1. Control and Status Register Field
2.5. Core Implementation x
2.5.1. Instruction Set Reference
1. About this Document
2. Nios® V/m Processor
3. Nios V Processor Reference Manual Archives
4. Document Revision History for the Nios® V Processor Reference Manual

2.3.4. Control and Status Registers

Nios® V/m processor's Control and Status Registers (CSR) is both readable and writable. Nios® V/m updates the CSR during the E-stage of the pipeline. If a memory or multicycle instruction is pending in M-stage, CSR write does not take place until M-stage completes this instruction. The application's write to CSR is processed by the core after M-stage completes, only if M-stage completes without an exception. If an exception is generated during M-stage, all CSR and other pending instructions are flushed and exception handle takes over.

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