tailieunhanh - Handbook of algorithms for physical design automation part 27

Handbook of Algorithms for Physical Design Automation part 27 provides a detailed overview of VLSI physical design automation, emphasizing state-of-the-art techniques, trends and improvements that have emerged during the previous decade. After a brief introduction to the modern physical design problem, basic algorithmic techniques, and partitioning, the book discusses significant advances in floorplanning representations and describes recent formulations of the floorplanning problem. The text also addresses issues of placement, net layout and optimization, routing multiple signal nets, manufacturability, physical synthesis, special nets, and designing for specialized technologies. It includes a personal perspective from Ralph Otten as he looks back on. | 242 Handbook of Algorithms for Physical Design Automation Module Locations Known or Unknown The whole point of floorplanning is to find suitable locations for modules and so it would seem that this information would be unknown at the start of the process. However there are scenarios when locations may be approximately known. For example if a chip is based off of an earlier generation of the same chip a floorplan architect who was familiar with the design of the original chip may wish to place modules in the same approximate locations manual or interactive floorplanning . Or if the floorplan is the result of engineering change order modifications . incremental floorplanning the floorplan architect may not want to radically change the locations of the modules. Alternatively the approximate locations may be the result of a preceding step such as dualization or force directed placement Chapter 8 or a quick rough placement as described in the next chapter. There is a substantial body of research related to the addition of location constraints such as range and boundary constraints discussed in Chapters 9 through 11 and symmetry constraints discussed later in this chapter to SA-based algorithms that address situations where there is some insight into module locations. Human Intervention The preceding section brings up another question. Should floorplanning be completely automated This is the ideal scenario but may be unrealistic because of the number of issues involved. Therefore it may be necessary to build tools that enable an interactive type of floorplanning paradigm that involves interaction between the architect and the tool. fixed-outline floorplanning Automated Floorplanning with Rectangular Modules Adya and Markov 3 present a fixed-outline floorplanning algorithm based on SA using sequence pairs. We refer to this as automated fixed-outline floorplanning to differentiate it from the incremental interactive formulation described in the