EURASIP Journal on Embedded Systems 
Volume 2008 (2008), Article ID 916867, 11 pages
doi:10.1155/2008/916867
Research Article

Multiple Word-Length High-Level Synthesis

Philippe Coussy, Ghizlane Lhairech-Lebreton, and Dominique Heller

Lab-STICC (CNRS), European University of Brittany, The Université de Bretagne-Sud, Centre de Recherche, BP 92116, F-56321 Lorient Cedex, France

Received 29 February 2008; Revised 5 May 2008; Accepted 21 July 2008

Recommended by Markus Rupp

Abstract

Digital signal processing (DSP) applications are nowadays widely used and their complexity is ever growing. The design of dedicated hardware accelerators is thus still needed in system-on-chip and embedded systems. Realistic hardware implementation requires first to convert the floating-point data of the initial specification into arbitrary length data (finite-precision) while keeping an acceptable computation accuracy. Next, an optimized hardware architecture has to be designed. Considering uniform bit-width specification allows to use traditional automated design flow. However, it leads to oversized design. On the other hand, considering non uniform bit-width specification allows to get a smaller circuit but requires complex design tasks. In this paper, we propose an approach that inputs a C/C++ specification. The design flow, based on high-level synthesis (HLS) techniques, automatically generates a potentially pipeline RTL architecture described in VHDL. Both bitaccurate integer and fixed-point data types can be used in the input specification. The generated architecture uses components (operator, register, etc.) that have different widths. The design constraints are the clock period and the throughput of the application. The proposed approach considers data word-length information in all the synthesis steps by using dedicated algorithms. We show in this paper the effectiveness of the proposed approach through several design experiments in the DSP domain.