Scheduling of Behavioral VHDL by Retiming Techniques

Abstract In this paper we present a new approach to the scheduling of behavioral VHDL descriptions for control-ow dominated applications containing a large number of nested conditionals and data dependent loops. The proposed algorithm is able to schedule and re-schedule descriptions for optimization subject to various cost functions. The timing of the I/O signals can be c ompletely xed, partially xed o r left to the scheduler. In this case the algorithm produces a schedule such that the number of clock cycles required f o r a c omplete execution of the behavioral description is minimized. Scheduling is performed a s a b ehavioral VHDL code transformation and allows taking advantage of all the power of commercial RT synthesis systems. The corresponding problem is solved b ased on an analogy to the retiming problem on RT-level networks which can be solved i n p olynomial time. The eciency of our approach is demonstrated on various examples

L'autoionisation dans les molécules biatomiques: un exemple d'autoionisation électrostatique dans CO.

A review is presented of the different types of autoionization which have been studied theoretically in diatomic molecules: electronic (or electrostatic), rotational, spin-orbit and vibrational autoionizations. An example involving a large number of vibrational channels is treated. It concerns the electrostatic autoionization in the 730-708 Angstöm wavelength region which appears in the CO photoionization spectrum. The structure observed at 721 Angstrôm is explained by the enhancement in intensity of numerous levels of Rydberg series converging to excited levels of the A 2Pi state caused by two autoionized Rydberg levels with a B 2Sigma+ core