Section: Software

ID.Fix: Infrastructure for the Design of Fixed-point Systems

Participants : Daniel Menard, Olivier Sentieys [corresponding author] , Romuald Rocher, Nicolas Simon.

Keywords: fixed-point arithmetic, source-to-source code transformation, accuracy optimization, dynamic range evaluation

The different techniques proposed by the team for fixed-point conversion are implemented on the ID.Fix infrastructure. The application is described with a C code using floating-point data types and different pragmas, used to specify parameters (dynamic, input/output word-length, delay operations) for the fixed-point conversion. This tool determines and optimizes the fixed-point specification and then, generates a C code using fixed-point data types (ac_fixed ) from Mentor Graphics. The infrastructure is made-up of two main modules corresponding to the fixed-point conversion (ID.Fix-Conv) and the accuracy evaluation (ID.Fix-Eval)

The different developments carried-out in 2012 allowed us to obtain a fixed-point conversion tool handling functions, conditional structures and repetitive structures having a fixed number of iterations during time. New optimization algorithms have been added. A simulator has been created to verify the results from our analytical approach. For the accuracy evaluation (Acc.Eval), conditional structures and correlation between noise sources have been considered. Some optimizations have been implemented to reduce the computing time and the division operator treatment has been integrated. A tutorial has also been created to install and use this tool.

The development of this tool has been achieved thanks to a University of Rennes graduate engineer from November 2011 in the context of DEFIS ANR project and different students during their training period.