8 References

several points within the design space are examined by the involved advice tool. Thus, predictions of the final result can be computed without completely synthesizing the whole design. This leads to a reasonable reduction of design time because only the design with the best estimated characteristics is given to logic synthesis for implementation. Future work will concentrate on bringing the advice to higher levels of abstraction, i.e. profiling of design characteristics in the behavioral domain. A fast computational algorithm for the discrete cosine transform. 12 because fidelity corresponds to the percentage of correctly predicted comparisons between design implementations. The fidelity of our experiments is 78, which indicates that estimates computed by the considered advice tool reflect the real situation quite good. Additionally, the time savings which can be achieved inside an design space exploration loop by using estimation instead of synthesis is considered. It has been found that the computation time for estimation is only about one third of logic synthesis time (see figure 9). Considered a logic synthesis path for one design as one time unit, design space exploration of our experiment consisting of nine design versions by logic synthesis takes (9 • 1 =) 9 time units. Using our methodology, the estimation phase takes (9 • 1/3 =) 3 time units plus one unit for the final implementation. Thus, in our experiment design time is reduced from 9 to 4 time units. So, using the presented approach far more points in design space can be explored within acceptable time limits. 7 Conclusion This paper shows the integration of RT-level advice into our system-level synthesis methodology. A standard C file is analyzed, HW is extracted and synthesized by our high-level synthesis tool PMOSS. For supporting a fast exploration of the design space, the final task of logic synthesis is done after a separate estimation phase. In this estimation phase Figure 8. Comparison of component count (estimated) and area (of synthesized design).