Related Information
Embedded Peripherals IP User Guide
1.4.2.2. Custom Components
You can also create custom components and integrate them in Nios II processor
systems. For performance-critical systems that spend most CPU cycles executing a
specific section of code, it is a common technique to create a custom peripheral that
implements the same function in hardware.
This approach offers a double performance benefit:
•
Hardware implementation is faster than software.
•
Processor is free to perform other functions in parallel while the custom peripheral
operates on data.
Related Information
Creating Platform Designer Components
1.4.2.3. Custom Instructions
Like custom peripherals, custom instructions allow you to increase system
performance by augmenting the processor with custom hardware. You can achieve
significant performance improvements, often on the order of 10 to 100 times, by
implementing performance-critical operations in hardware using custom instruction
logic.
The custom logic is integrated into the Nios II processor’s arithmetic logic unit (ALU).
Similar to native Nios II instructions, custom instruction logic can take values from up
to two source registers and optionally write back a result to a destination register.
Because the processor is implemented on reprogrammable Intel FPGAs, software and
hardware engineers can work together to iteratively optimize the hardware and test
the results of software running on hardware.
From the software perspective, custom instructions appear as machine-generated
assembly macros or C functions, so programmers do not need to understand assembly
language to use custom instructions.
1.4.3. Automated System Generation
Intel FPGA’s Platform Designer system integration tools fully automate the process of
configuring processor features and generating a hardware design that you program in
an Intel FPGA device. The Platform Designer graphical user interface (GUI) enables
you to configure Nios II processor systems with any number of peripherals and
memory interfaces. You can create entire processor systems without performing any
schematic or HDL design entry. Platform Designer can also import HDL design files,
providing an easy mechanism to integrate custom logic in a Nios II processor system.
After system generation, you can download the design onto a board, and debug
software executing on the board. To the software developer, the processor architecture
of the design is set. Software development proceeds in the same manner as for
traditional, nonconfigurable processors.
1. Introduction
NII-PRG | 2018.04.18
Nios II Processor Reference Guide
12
