Exploring High-Level Synthesis with Bambu-HLS: A Journey into Efficient Hardware Design

In the ever-evolving landscape of hardware design, transitioning from traditional methods to high-level synthesis (HLS) has been a game-changer. HLS tools enable designers to work at a higher level of abstraction, allowing for faster and more efficient hardware design processes. One such powerful tool in this domain is Bambu-HLS.

In this blog post, we’ll dive into the capabilities and features of Bambu-HLS, leveraging the repository srsapireddy/Bambu-HLS as our guide.

What is Bambu-HLS?

Bambu-HLS is an open-source high-level synthesis tool that converts C/C++ code into hardware description language (HDL). It aims to streamline the hardware design process by allowing designers to write high-level code, which Bambu then translates into an efficient hardware implementation. This approach significantly reduces the complexity and time required for designing custom hardware.

Key Features of Bambu-HLS

1. High-Level Abstraction: Bambu-HLS allows designers to write hardware designs in C/C++, which are then synthesized into HDL. This high-level abstraction simplifies the design process and makes it accessible to software engineers.
2. Optimization: The tool includes various optimization techniques to generate efficient hardware implementations. These optimizations ensure that the resulting hardware is functionally correct and performance-optimized.
3. Extensibility: Bambu-HLS is open-source, meaning you can extend and customize it according to your needs. This flexibility makes it a valuable tool for research and development in hardware design.
4. Comprehensive Documentation: The repository includes detailed documentation and example projects, making it easy for new users to get started and understand Bambu-HLS's capabilities.

Getting Started with Bambu-HLS:

To get started with Bambu-HLS, you need to install dependencies. Here’s a step-by-step guide to setting up and using Bambu-HLS:

Install Dependencies:

sudo apt-get install -y --no-install-recommends build-essential ca-certificates gcc-multilib git iverilog verilator wget

Download Bambu-HLS AppImage:

wget https://release.bambu.bambu.tech.eu/release/bambu-0.9.7.AppImage

Make the AppImage Executable:

chmod a+x bambu-0.9.7.AppImage

Add the ‘universe’ Repository:

sudo add-apt-repository universe

Update Package Lists:

sudo apt-get update

Running Bambu:

./bambu-0.9.7.AppImage

A Practical Example

Let’s walk through a practical example to illustrate how Bambu-HLS can be used to design hardware.

1. Write High-Level Code: Write your hardware logic in C/C++. For instance, consider a simple function (saved as ex_tut3.c):

long func(int,int,int,int);
main()
{
 int j;
 int k;
 
 int c;
 int d;
 
 int res = func(j,k,c,d);
 return 0;
}

long func(int j, int k, int c, int d)
{
 int i = 0;
 if(c > 2){
  i = j - k;
 } else if (d < 5) {
  i = j + k;
 } else {
  i = 12;
 }
return i;
}

2. Synthesize to HDL: Use Bambu-HLS to synthesize the C code into HDL. This step involves running the Bambu tool with appropriate commands, which are documented in the repository.

./bambu-0.9.7.AppImage Lab/Tutorial3/ex_tut3.c --top-fname=func

3. Simulate and Verify (func.v file is created): After generating the HDL, use simulation tools to verify the correctness of the synthesized hardware. Bambu-HLS provides integration with simulation tools to facilitate this process.

RTL description of C file

4. Optimize and Iterate: Apply various optimization techniques provided by Bambu-HLS to improve the performance of your hardware design. Iterate through the design-simulation-optimization cycle to achieve the desired results.

Bambu-HLS is a powerful tool that brings the advantages of high-level synthesis to hardware design. Allowing designers to work at a higher level of abstraction simplifies the design process and reduces development time.

Whether you’re a seasoned hardware designer or a software engineer venturing into hardware design, Bambu-HLS offers the tools and flexibility to bring your ideas to life. Happy designing!