AN 977: Nios® V Processor Custom Instruction

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ID 773194
Date 4/14/2023
Public
Document Table of Contents
Document Table of Contents x
1. Nios® V Processor Custom Instruction Overview 2. Custom Instruction Hardware Interface 3. Custom Instruction Software Interface 4. Designing with Intel® Quartus® Prime and Platform Designer 5. Document Revision History for AN 977: Nios® V Processor Custom Instruction
1. Nios® V Processor Custom Instruction Overview x
1.1. Implementing Custom Instruction 1.2. Implementing Custom Instruction Logic Block 1.3. Implementing Custom Instruction Software
2. Custom Instruction Hardware Interface x
2.1. Custom Instruction Types 2.2. Multicycle Custom Instructions 2.3. Extended Custom Instruction 2.4. External Interface Custom Instructions
2.2. Multicycle Custom Instructions x
2.2.1. Multicycle Custom Instruction Ports 2.2.2. Multicycle Custom Instruction Timing 2.2.3. Implementing Combinational Custom Instruction
2.3. Extended Custom Instruction x
2.3.1. Extended Custom Instruction Timing
3. Custom Instruction Software Interface x
3.1. Custom Instruction Software C Macro 3.2. Custom Instruction Assembly Language Interface 3.3. Custom Instruction Word Format
3.2. Custom Instruction Assembly Language Interface x
3.2.1. Custom Instruction Assembly Language Syntax
3.3. Custom Instruction Word Format x
3.3.1. Selector and Extension Indexes 3.3.2. ALU Switch 3.3.3. User-defined Immediate
4. Designing with Intel® Quartus® Prime and Platform Designer x
4.1. Interface Signals 4.2. Custom Instruction Manager 4.3. Custom Instruction Subordinate
4.1. Interface Signals x
4.1.1. alu_result port 4.1.2. ctrl port
4.2. Custom Instruction Manager x
4.2.1. Hardware Interfaces Table 4.2.2. Software C-Macro Table
4.3. Custom Instruction Subordinate x
4.3.1. Writing the Custom Instruction HDL File 4.3.2. Opening the Component Editor 4.3.3. Specifying the Custom Instruction Component Type 4.3.4. Displaying the Custom Instruction Block Symbol 4.3.5. Adding the Custom Instruction HDL File 4.3.6. Configuring the Custom Instruction Parameter Type 4.3.7. Setting Up the Custom Instruction Interfaces 4.3.8. Saving and Adding the Custom Instruction 4.3.9. Generating and Compiling the Processor System
1. Nios® V Processor Custom Instruction Overview
2. Custom Instruction Hardware Interface
3. Custom Instruction Software Interface
4. Designing with Intel® Quartus® Prime and Platform Designer
5. Document Revision History for AN 977: Nios® V Processor Custom Instruction

3.3.2. ALU Switch

The funct3 field determines the ALU switch. Using data0 and data1 as inputs, the ALU switch picks an ALU operation, and delivers the result as alu_result at the start of the custom instruction. You can use the alu_result, concurrently with the same data0 and data1 in the custom instruction. When applying this feature, Intel recommends you to hardcode the funct3 value in the Platform Designer.

Table 9.  ALU Switch Options
funct3 ALU Operation alu_result[31:0]
000 ADD

Addition of data0 and data1.

001 Reserved N/A
010 SLT (Set on Less Than (signed)) 1 if data0 < data1, 0 otherwise.
011 SLTU (Set on Less Than (unsigned)) 1 if data0 < data1, 0 otherwise.
100 XOR (Exclusive OR) Bitwise XOR operation of data0 and data1.
101 Reserved N/A
110 OR Bitwise OR operation of data0 and data1.
111 AND Bitwise AND operation of data0 and data1.
Figure 11. ALU Switch Block Diagram
Figure 12. ALU Switch Timing Diagram with AND Operation
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