Nios® V Processor Reference Manual

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ID 683632
Date 11/15/2021
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Document Table of Contents
Document Table of Contents x
1. About this Document 2. Nios® V/m Processor 3. 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. Control and Status Registers 2.3.4. Exception Controller 2.3.5. Interrupt Controller 2.3.6. Memory and I/O Organization 2.3.7. RISC-V based Debug Module
2.3.5. Interrupt Controller x
2.3.5.1. Timer and Software Interrupt Module
2.3.6. Memory and I/O Organization x
2.3.6.1. Instruction and Data Buses
2.3.6.1. Instruction and Data Buses x
2.3.6.1.1. Instruction Manager Port 2.3.6.1.2. Data Manager Port 2.3.6.1.3. Address Map
2.3.7. RISC-V based Debug Module x
2.3.7.1. Debug Mode 2.3.7.2. Halt from Debug Module 2.3.7.3. Debug Implementation 2.3.7.4. Abstract Commands in Debug Mode 2.3.7.5. 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. Document Revision History for the Nios® V Processor Reference Manual

2.3.2. Arithmetic Logic Unit

The Arithmetic Logic Unit (ALU) operates on data stored in general-purpose registers. ALU operations take one or two inputs from registers and store the result back into the register. The ALU supports four fundamental data operations described in the following table.

Table 5.  Supported Operations
Category Description
Arithmetic The ALU supports addition and subtraction on signed and unsigned operands.
Relational The ALU supports the equal, not-equal, greater-than-or-equal, and less-than relational operations (==, != >=, <) .
Logical The ALU supports AND, OR, NOR, and XOR logical operations.
Shift The ALU supports logical and arithmetic shift operations.

For load/store instructions, Nios® V/m processor uses ALU to calculate the memory address. For conditional control transfer instructions, Nios® V/m processor uses the relational operations in ALU area to decide whether to take the branch or not.

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