Nios® V Processor Reference Manual

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ID 683632
Date 1/27/2025
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Document Table of Contents
Document Table of Contents x
1. Overview 2. Nios® V/c Processor 3. Nios® V/m Processor 4. Nios® V/g Processor 5. Nios V Processor Reference Manual Archives 6. Document Revision History for the Nios® V Processor Reference Manual
1. Overview x
1.1. Quartus® Prime Software Support
2. Nios® V/c 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. Instruction Cycles 2.3.5. Memory and I/O Organization 2.3.6. Error Correction Code (ECC)
2.3.5. Memory and I/O Organization x
2.3.5.1. Instruction and Data Buses 2.3.5.2. Address Map
2.3.5.1. Instruction and Data Buses x
2.3.5.1.1. Instruction Manager Port 2.3.5.1.2. Data Manager Port 2.3.5.1.3. Choosing a Suitable Interface
2.4. Programming Model x
2.4.1. Privilege Levels
2.5. Core Implementation x
2.5.1. Instruction Set Reference
3. Nios® V/m Processor x
3.1. Processor Performance Benchmarks 3.2. Processor Pipeline 3.3. Processor Architecture 3.4. Programming Model 3.5. Core Implementation
3.1. Processor Performance Benchmarks x
3.1.1. Pipelined 3.1.2. Non-pipelined
3.2. Processor Pipeline x
3.2.1. Pipelined Architecture 3.2.2. Non-pipelined Architecture
3.3. Processor Architecture x
3.3.1. General-Purpose Register File 3.3.2. Arithmetic Logic Unit 3.3.3. Reset and Debug Signals 3.3.4. Control and Status Registers 3.3.5. Instruction Cycles 3.3.6. Trap Controller (CLINT) 3.3.7. Memory and I/O Organization 3.3.8. RISC-V based Debug Module 3.3.9. Error Correction Code (ECC)
3.3.6. Trap Controller (CLINT) x
3.3.6.1. Related Control and Status Register 3.3.6.2. Direct Mode 3.3.6.3. Vectored Mode
3.3.6.1. Related Control and Status Register x
3.3.6.1.1. Machine Status Register (mstatus) 3.3.6.1.2. Machine Trap-Vector Base-Address Register (mtvec) 3.3.6.1.3. Machine Interrupt Register (mip and mie) 3.3.6.1.4. Machine Exception Program Counter Register (mepc) 3.3.6.1.5. Machine Cause Register (mcause) 3.3.6.1.6. Machine Trap Value Register (mtval)
3.3.6.2. Direct Mode x
3.3.6.2.1. Hardware Implementation 3.3.6.2.2. Software Implementation
3.3.6.3. Vectored Mode x
3.3.6.3.1. Hardware Implementation 3.3.6.3.2. Software Implementation
3.3.7. Memory and I/O Organization x
3.3.7.1. Instruction and Data Buses 3.3.7.2. Address Map
3.3.7.1. Instruction and Data Buses x
3.3.7.1.1. Instruction Manager Port 3.3.7.1.2. Data Manager Port 3.3.7.1.3. Choosing a Suitable Interface
3.3.8. RISC-V based Debug Module x
3.3.8.1. Debug Module 3.3.8.2. Abstract Commands 3.3.8.3. Program Buffer 3.3.8.4. Debug Mode 3.3.8.5. Hardware Trigger Module 3.3.8.6. JTAG Debug Transport Module 3.3.8.7. Nios® V Processor Implementation
3.3.8.1. Debug Module x
3.3.8.1.1. Reset/Halt/Run Control 3.3.8.1.2. Hart States 3.3.8.1.3. Debug Module Register
3.3.8.2. Abstract Commands x
3.3.8.2.1. Access Register Command 3.3.8.2.2. Using Access Register Command
3.3.8.3. Program Buffer x
3.3.8.3.1. Using Program Buffer
3.3.8.4. Debug Mode x
3.3.8.4.1. Enter Debug Mode 3.3.8.4.2. Exit Debug Mode 3.3.8.4.3. Core Debug Registers
3.3.8.5. Hardware Trigger Module x
3.3.8.5.1. Trigger Registers 3.3.8.5.2. Type of Address/Data Match Triggers 3.3.8.5.3. Using Triggers
3.3.8.6. JTAG Debug Transport Module x
3.3.8.6.1. JTAG DTM Registers 3.3.8.6.2. Accessing Debug Module Interface
3.4. Programming Model x
3.4.1. Privilege Levels 3.4.2. Control and Status Registers (CSR) Mapping
3.4.1. Privilege Levels x
3.4.1.1. Machine Mode (M-mode) 3.4.1.2. Debug Mode (D-mode)
3.4.2. Control and Status Registers (CSR) Mapping x
3.4.2.1. Control and Status Register Field 3.4.2.2. Memory Mapped Registers Fields
3.5. Core Implementation x
3.5.1. Instruction Set Reference
4. Nios® V/g Processor x
4.1. Processor Performance Benchmarks 4.2. Processor Pipeline 4.3. Processor Architecture 4.4. Programming Model 4.5. Core Implementation
4.3. Processor Architecture x
4.3.1. General-Purpose Register File 4.3.2. Arithmetic Logic Unit 4.3.3. Multipy and Divide Units 4.3.4. Floating-Point Unit 4.3.5. Custom Instruction 4.3.6. Instruction Cycles 4.3.7. Reset and Debug Signals 4.3.8. Control and Status Registers 4.3.9. Trap Controller (CLINT) 4.3.10. Memory and I/O Organization 4.3.11. RISC-V based Debug Module 4.3.12. Error Correction Code (ECC) 4.3.13. Branch Prediction 4.3.14. Lockstep Module
4.3.4. Floating-Point Unit x
4.3.4.1. IEEE 754 Exception Conditions 4.3.4.2. Floating Point Operations
4.3.4.2. Floating Point Operations x
4.3.4.2.1. Floating Point Classification
4.3.9. Trap Controller (CLINT) x
4.3.9.1. Related Control and Status Register 4.3.9.2. Direct Mode 4.3.9.3. Vectored Mode
4.3.9.1. Related Control and Status Register x
4.3.9.1.1. Machine Status Register (mstatus) 4.3.9.1.2. Machine Trap-Vector Base-Address Register (mtvec) 4.3.9.1.3. Machine Interrupt Register (mip and mie) 4.3.9.1.4. Machine Exception Program Counter Register (mepc) 4.3.9.1.5. Machine Cause Register (mcause) 4.3.9.1.6. Machine Trap Value Register (mtval) 4.3.9.1.7. Machine Second Trap Value Register (mtval2)
4.3.9.2. Direct Mode x
4.3.9.2.1. Hardware Implementation 4.3.9.2.2. Software Implementation
4.3.9.3. Vectored Mode x
4.3.9.3.1. Hardware Implementation 4.3.9.3.2. Software Implementation
4.3.10. Memory and I/O Organization x
4.3.10.1. Instruction and Data Buses 4.3.10.2. Address Map 4.3.10.3. Cache Memory 4.3.10.4. Tightly Coupled Memory
4.3.10.1. Instruction and Data Buses x
4.3.10.1.1. Instruction Manager Port 4.3.10.1.2. Data Manager Port
4.3.10.3. Cache Memory x
4.3.10.3.1. Instruction Cache 4.3.10.3.2. Data Cache 4.3.10.3.3. Configurable Cache Memory 4.3.10.3.4. Bypassing Cache (Peripheral Region) 4.3.10.3.5. Using Cache Memory Effectively
4.3.10.4. Tightly Coupled Memory x
4.3.10.4.1. Instruction and Data Tightly Coupled Memory 4.3.10.4.2. Accessing Tightly Coupled Memory 4.3.10.4.3. Using Tightly Coupled Memory Effectively
4.3.11. RISC-V based Debug Module x
4.3.11.1. Debug Module 4.3.11.2. Abstract Commands 4.3.11.3. Program Buffer 4.3.11.4. Debug Mode 4.3.11.5. Hardware Trigger Module 4.3.11.6. JTAG Debug Transport Module 4.3.11.7. Nios® V Processor Implementation
4.3.11.1. Debug Module x
4.3.11.1.1. Reset/Halt/Run Control 4.3.11.1.2. Hart States 4.3.11.1.3. Debug Module Register
4.3.11.2. Abstract Commands x
4.3.11.2.1. Access Register Command 4.3.11.2.2. Using Access Register Command
4.3.11.3. Program Buffer x
4.3.11.3.1. Using Program Buffer
4.3.11.4. Debug Mode x
4.3.11.4.1. Enter Debug Mode 4.3.11.4.2. Exit Debug Mode 4.3.11.4.3. Core Debug Registers
4.3.11.5. Hardware Trigger Module x
4.3.11.5.1. Trigger Registers 4.3.11.5.2. Type of Address/Data Match Triggers 4.3.11.5.3. Using Triggers
4.3.11.6. JTAG Debug Transport Module x
4.3.11.6.1. JTAG DTM Registers 4.3.11.6.2. Accessing Debug Module Interface
4.3.12. Error Correction Code (ECC) x
4.3.12.1. ECC Interface 4.3.12.2. ECC Error Injection 4.3.12.3. Affected CSR during ECC Event
4.4. Programming Model x
4.4.1. Privilege Levels 4.4.2. Control and Status Registers (CSR) Mapping (CLINT)
4.4.1. Privilege Levels x
4.4.1.1. Machine Mode (M-mode) 4.4.1.2. Debug Mode (D-mode)
4.4.2. Control and Status Registers (CSR) Mapping (CLINT) x
4.4.2.1. Control and Status Register Field (CLINT) 4.4.2.2. Memory Mapped Registers Fields
4.5. Core Implementation x
4.5.1. Instruction Set Reference
1. Overview
2. Nios® V/c Processor
3. Nios® V/m Processor
4. Nios® V/g Processor
5. Nios V Processor Reference Manual Archives
6. Document Revision History for the Nios® V Processor Reference Manual

4.3.12.1. ECC Interface

The ECC interface allows external logic to monitor ECC errors in the Nios® V/g processor. The interface is a conduit and made up of two output signals.
  • cpu_ecc_status: Indicates the error status.
  • cpu_ecc_source: Indicates the error source
Table 136.   cpu_ecc_status
2-bits Encoding ECC Status Effects on Software Next Action
2’b00 No ECC event None None
2’b01 Reserved Not Applicable Not Applicable
2’b10 Correctable single bit ECC error None None
2’b11 Un-correctable ECC error Likely fatal and halts processor Reset either processor or entire system
Table 137.   cpu_ecc_source
4-bits Encoding ECC Source Available
4’b0000 No ECC event Always
4’b0001 General Purpose Register (GPR) Always
4’b0010 Instruction Cache Data RAM Always
4’b0011 Instruction Cache Tag RAM Always
4’b0100 Data Cache Data RAM Always
4’b0101 Data Cache Tag RAM Always
4’b0110 Instruction TCM1 When Instruction TCM1 is present
4’b0111 Instruction TCM2 When Instruction TCM2 is present
4’b1000 Data TCM1 When Data TCM1 is present
4’b1001 Data TCM2 When Data TCM2 is present
4’b1010 Floating Point Register (FPR) When FPU is present
4’b1111 Reserved Not Applicable
Level Two Title