Support for Arbitrary Fixed-Point Numbers

[chhzh123]

Hi, thanks for your excellent work to improve the scalability and performance of HLS, which is very helpful for hardware accelerator development.

After looking through your paper and code, I am wondering if there are any supports for arbitrary fixed-point numbers in ScaleHLS. I only found one test case involving a fixed integer in your repo (https://github.com/hanchenye/scalehls/blob/master/test/EmitHLSCpp/test_signature.mlir#L36). Though you have included the <ap_fixed> library in the generated C++ HLS code, it seems the fixed-point arithmetics have not been implemented in MLIR. Then how can users do quantization in ScaleHLS?

[hanchenye]

Hi @chhzh123, thanks for your interest! Unfortunately, currently ScaleHLS only supports the built-in types implemented in MLIR and cannot model the ap_fixed types of Xilinx. A related discussion happened here which you can refer to a bit.

[chhzh123]

Thanks for your quick reply! The attached discussion is very helpful. I will stay tuned for the updates.