Nios® V Processor Reference Manual

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ID 683632
Date 7/26/2024
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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. Memory and I/O Organization 2.3.5. Error Correction Code (ECC)
2.3.4. Memory and I/O Organization x
2.3.4.1. Instruction and Data Buses 2.3.4.2. Address Map
2.3.4.1. Instruction and Data Buses x
2.3.4.1.1. Instruction Manager Port 2.3.4.1.2. Data Manager Port
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. Trap Controller 3.3.6. Memory and I/O Organization 3.3.7. RISC-V based Debug Module 3.3.8. Error Correction Code (ECC)
3.3.5. Trap Controller x
3.3.5.1. Exception Handling 3.3.5.2. Interrupt Handling
3.3.5.2. Interrupt Handling x
3.3.5.2.1. Timer and Software Interrupt Module
3.3.6. Memory and I/O Organization x
3.3.6.1. Instruction and Data Buses 3.3.6.2. Address Map
3.3.6.1. Instruction and Data Buses x
3.3.6.1.1. Instruction Manager Port 3.3.6.1.2. Data Manager Port
3.3.7. RISC-V based Debug Module x
3.3.7.1. Debug Mode 3.3.7.2. Halt from Debug Module 3.3.7.3. Trigger 3.3.7.4. Abstract Commands in Debug Mode 3.3.7.5. Hardware/Software 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
3.5. 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. Reset and Debug Signals 4.3.7. Control and Status Registers 4.3.8. Trap Controller 4.3.9. Memory and I/O Organization 4.3.10. RISC-V based Debug Module 4.3.11. Error Correction Code (ECC)
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
4.3.8. Trap Controller x
4.3.8.1. Exception Controller 4.3.8.2. Interrupt Controller
4.3.8.2. Interrupt Controller x
4.3.8.2.1. Timer and Software Interrupt Module
4.3.9. Memory and I/O Organization x
4.3.9.1. Instruction and Data Buses 4.3.9.2. Address Map 4.3.9.3. Cache Memory 4.3.9.4. Tightly Coupled Memory
4.3.9.1. Instruction and Data Buses x
4.3.9.1.1. Instruction Manager Port 4.3.9.1.2. Data Manager Port
4.3.9.3. Cache Memory x
4.3.9.3.1. Instruction Cache 4.3.9.3.2. Data Cache 4.3.9.3.3. Configurable Cache Memory 4.3.9.3.4. Bypassing Cache (Peripheral Region) 4.3.9.3.5. Using Cache Memory Effectively
4.3.9.4. Tightly Coupled Memory x
4.3.9.4.1. Instruction and Data Tightly Coupled Memory 4.3.9.4.2. Accessing Tightly Coupled Memory 4.3.9.4.3. Using Tightly Coupled Memory Effectively
4.3.10. RISC-V based Debug Module x
4.3.10.1. Debug Mode 4.3.10.2. Halt from Debug Module 4.3.10.3. Trigger 4.3.10.4. Abstract Commands in Debug Mode 4.3.10.5. Hardware/Software Interface
4.4. Programming Model x
4.4.1. Privilege Levels 4.4.2. Control and Status Registers (CSR) Mapping
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 x
4.4.2.1. Control and Status Register Field
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

4.3.9.1.1. Instruction Manager Port

Nios® V/g processor instruction bus is implemented as a 32-bit AMBA* 4 AXI manager port.

The instruction manager port:
  • Performs a single function: it fetches instructions to be executed by the processor.
  • Does not perform any write operations.
  • Can issue successive read requests before data return from prior requests.
  • Can prefetch sequential instructions.
  • Always retrieves 32-bit of data. Every instruction fetch returns a full instruction word, regardless of the width of the target memory. The widths of memory in the Nios® V/g processor system is not applicable to the programs. Instruction address is always aligned to a 32-bit word boundary.
  • Implements a burst adapter because it is bursting capable and can issue wrapping burst.
Table 70.  Instruction Interface Signals
Interface Signal Role Width Direction
Write Address Channel awaddr Unused [31:0] Output
awlen Unused [7:0] Output
awsize Unused [2:0] Output
awburst Unused [1:0] Output
awprot Unused [2:0] Output
awvalid Unused 1 Output
awready Unused 1 Input
Write Data Channel wdata Unused [31:0] Output
wstrb Unused [3:0] Output
wlast Unused 1 Output
wvalid Unused 1 Output
wready Unused 1 Input
Write Response Channel bresp Unused [1:0] Input
bvalid Unused 1 Input
bready Unused 1 Output
Read Address Channel araddr

Instruction Address

(Program Counter)

 [31:0] Output
arlen

Read burst length

• 0 for peripheral region access

• 7 for cacheable region access

 [7:0] Output
arsize Constant 2 (4 bytes) [2:0] Output
arburst Constant 2 (WRAP) [1:0] Output
arprot Unused [2:0] Output
arvalid Instruction address valid 1 Output
arready

Instruction address ready

(from memory)

 1 Input
Read Data Channel rdata Instruction [31:0] Input
rresp Instruction response: Non-zero value denotes instruction access fault exception [1:0] Input
rlast Last transfer in a read burst 1 Input
rvalid Instruction valid 1 Input
rready Constant 1 1 Output
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