Duplicating same argument of function to realize efficient hardware for high-level synthesis

Abstract

High-level synthesis (HLS) automatically converting software into hardware is a promising technology to reduce the design burden significantly. However, to use HLS technology efficiently, software program must be described considering the hardware organization that HLS tool will generate. We are developing the HLS image processing library. However, some caution is required when using HLS for programs that read images. When the same image is read through an argument of the function, the input port corresponding to this argument on the hardware generated by HLS tool may cause the port conflict. As a result, the image reading is made serialized and this serialization disturbs the performance of the data path well pipelined by the HLS tool. This paper shows how to write a software program to avoid this problem. In addition, we adapt this method to two image processing and evaluate the effect of our proposal to them.