AN 977: Nios® V Processor Custom Instruction

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ID 773194
Date 4/14/2023
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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 C Macros in system.h
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

4.2.2. Software C-Macro Table

Unlike the Hardware Interfaces Table, the Software C-Macro Table configures the custom instruction software C Macro for software development. Note that, any assignment made need to correlates to the earlier assignments in Hardware Interfaces Table.

Select the symbol + to add new assignment, and - to delete it. Each assignment results in a single Nios® V processor custom instruction Software C Macro in the system.h file.

Table 12.  Software C-Macro Table Parameter
Parameter Description
Opcode
  • Correlate to the Hardware Interfaces Table.
  • The required selector index.
  • String assignment, with CUSTOM0, CUSTOM1, , CUSTOM2, or CUSTOM3 as options.
funct7[6:4]
  • Correlate to the Hardware Interfaces Table.
  • As optional selector index, or user-defined immediate.
  • 3-bits assignment, with available logic of 0, 1, or x.
  • Assign any bits as x to register it as input argument in the C Macro.
funct7[3:0]
  • As extension index, or user-defined immediate.
  • 4-bits assignment, with available logic of 0, 1, or x.
  • Assign any bits as x to register it as input argument in the C Macro.
funct3[2:0]
  • As extension index, ALU switch, or user-defined immediate.
  • 3-bits assignment, with available logic of 0, 1, or x.
  • Assign any bits as x to register it as input argument in the C Macro.
mnemonic
  • Define the mnemonic name of the custom instruction.
  • Intel recommends you to capitalize the name.
Figure 16. Example Assignments in Software C-Macro Table

C Macros in system.h 

#define CUSTOM_0_000(VAL_1, VAL_2) ({ \
 int output; \
 asm volatile (".insn r 0x0B, 0x0, 0x0, %[out], %[input1], %[input2]" \
    : [out] "=r" (output) \
    : [input1] "r" (VAL_1), [input2] "r" (VAL_2)); \
    output;  \
})

#define CUSTOM_0_111(VAL_1, VAL_2) ({ \
 int output; \
 asm volatile (".insn r 0x0B, 0x0, 0x70, %[out], %[input1], %[input2]" \
    : [out] "=r" (output) \
    : [input1] "r" (VAL_1), [input2] "r" (VAL_2)); \
    output;  \
})

#define CUSTOM_1_XXX(VAL_1, VAL_2, F3, F7) ({ \
 int output; \
 asm volatile (".insn r 0x2B, %[FUNCT3], (0x0 | (%[FUNCT7]<<0)), %[out], %[input1], %[input2]" \
    : [out] "=r" (output) \
    : [input1] "r" (VAL_1), [input2] "r" (VAL_2), [FUNCT3] "i" (F3), [FUNCT7] "i" (F7)); \
    output;  \
})

#define CUSTOM_2_0XX(VAL_1, VAL_2, F3, F7) ({ \
 int output; \
 asm volatile (".insn r 0x5B, %[FUNCT3], (0x10 | (%[FUNCT7]<<0)), %[out], %[input1], %[input2]" \
    : [out] "=r" (output) \
    : [input1] "r" (VAL_1), [input2] "r" (VAL_2), [FUNCT3] "i" (F3), [FUNCT7] "i" (F7)); \
    output;  \
})

#define CUSTOM_3_10X(VAL_1, VAL_2) ({ \
 int output; \
 asm volatile (".insn r 0x7B, 0x0, 0x50, %[out], %[input1], %[input2]" \
    : [out] "=r" (output) \
    : [input1] "r" (VAL_1), [input2] "r" (VAL_2)); \
    output;  \
})
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