tailieunhanh - Handbook of algorithms for physical design automation part 31

Handbook of Algorithms for Physical Design Automation part 31 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. | 282 Handbook of Algorithms for Physical Design Automation the design unroutable. A strategy of simple uniform spreading of the design may work well for dense designs but can unnecessarily hurt timing for sparse designs. Thus white space management is absolutely required in modern placement algorithms to achieve better timing and routability. 3. Mixed-size placement For the past few decades standard cell placement is considered as the norm. A standard cell based design consists of circuit elements called standard cells whose heights remain the same and the placement problem is to place these circuit elements within regular circuit row boundaries Figure . In today s design methodology designers are encouraged to take hierarchical or semihierarchical design approaches with reusable internal third-party IPs to reduce design turnaround time. As a result a wider distribution of circuit element sizes is observed during placement. In some sense mixed-size placement Figure as opposed to uniform-height placement of standard cells is a more complicated problem because these large macro blocks can cause a serious challenge during placement legalization. Also these chunky blocks play an important role in determining final timing performance. Hence the early placement of large macros during floorplanning or flat placement is an important problem in a modern timing closure flow. To provide further flexibility in floorplanning and placement sometimes all the standard cells as well as large macros are considered as movable objects and are placed simultaneously. This new problem is called floorplacement 8 . In general today s placement algorithms must be able to handle a wide range of object sizes because the trend indicates that more IP blocks are included in a design. 4. Region constraints movebounds In a hierarchical design methodology the functionality of a design is logically partitioned first and floorplanning is executed on the set of logically partitioned blocks