Beyond the arithmetic constraint: depth-optimal mapping of logic chains in reconfigurable fabrics

Look-up table based FPGAs have migrated from a niche technology for design prototyping to a valuable end-product component and, in some cases, a replacement for general purpose processors and ASICs alike. One way architects have bridged the performance gap between FPGAs and ASICs is through the inclusion of specialized components such as multipliers, RAM modules, and microcontrollers. Another dedicated structure that has become standard in reconfigurable fabrics is the arithmetic carry chain. Currently, it is only used to map arithmetic operations as identified by HDL macros. For non-arithmetic operations, it is an idle but potentially powerful resource.;Obstacles to using the carry chain for generic logic operations include lack of architectural and computer-aided design support. Current carry-select architectures facilitate carry chain reuse, although they do so only for (K-1)-input operations. Additionally, hardware description language (HDL) macros are the only recourse for a designer wishing to map generic logic chains in a carry-select architecture. A novel architecture that allows the full K-input operational capacity of the carry chain to be harnessed is presented as a solution to current architectural limitations. It is shown to have negligible impact on logic element area and delay. Using only two additional 2:1 pass transistor multiplexers, it enables the transmission of a K-input operation to the carry chain and general routing simultaneously. To successfully identify logic chains in an arbitrary Boolean network, ChainMap is presented as a novel technology mapping algorithm. ChainMap creates delay-optimal generic logic chains in polynomial time without HDL macros. It maps both arithmetic and non-arithmetic logic chains whenever depth increasing nodes, which increase logic depth but not routing depth, are encountered. Use of the chain is not reserved for arithmetic, but rather any set of gates exhibiting similar characteristics. By using the carry chain as a generic, near zero-delay adjacent cell interconnection structure a potential average optimal speedup of 1.4x is revealed. Post place and route experiments indicate that ChainMap solutions perform similarly to HDL chains when cluster resources are abundant and significantly better in cluster-constrained arrays

Intelligent optimization of Circuit placement on FPGA

Field programmable gate arrays (FPGAs) have revolutionized the way digital systems are designed and built over the past decade. With architectures capable of holding tens of millions of logic gates on the horizon and planned integration of configurable logic into system-on-chip platforms, the versatility of programmable devices expected to increase dramatically. Placement is one of the vital steps in mapping a design into FPGA in order to take best advantage of the resources and flexibility provided by it. Here, we propose to test techniques of Placement Optimization on MCNC Benchmark circuits. PSO (Particle Swarm Optimization) has been implemented on circuit netlist with bounding box as cost function. Alternate cost functions were also employed to verify efficiency of optimization. Furthermore, lazy descent was introduced into the algorithm to impede premature convergence. Different values of acceleration and weighing factors were used in the implementation and corresponding convergence results were analyzed. Keywords- FPGA Placement; Particle Swarm Optimization; MCNC Benchmarks Circuits; Bounding Box driven Placement

A Basic, Four Logic Cluster, Disjoint Switch Connected FPGA Architecture

This paper seeks to describe the process of developing a new FPGA architecture from nothing, both in terms of knowledge about FPGAs and in initial design material. Specifically, this project set out to design an FPGA architecture which can implement a simple state machine type design with 10 inputs, 10 outputs and 10 states. The open source Verilog-to-Routing FPGA CAD flow tool was used in order to synthesize, place, and route HDL files onto the architecture. This project was completed in terms of the spirit of the original goals of implementing an FPGA from scratch. Although, the project resulted in an architecture which slightly underperformed in its ability to route 100% of 10 input, 10 output, 10 state designs due to the general place and route algorithm used and the lack of non-contrived 10 input 10 output 10 state FSM designs

A Field Programmable Gate Array Architecture for Two-Dimensional Partial Reconfiguration

Reconfigurable machines can accelerate many applications by adapting to their needs through hardware reconfiguration. Partial reconfiguration allows the reconfiguration of a portion of a chip while the rest of the chip is busy working on tasks. Operating system models have been proposed for partially reconfigurable machines to handle the scheduling and placement of tasks. They are called OS4RC in this dissertation. The main goal of this research is to address some problems that come from the gap between OS4RC and existing chip architectures and the gap between OS4RC models and practical applications. Some existing OS4RC models are based on an impractical assumption that there is no data exchange channel between IP (Intellectual Property) circuits residing on a Field Programmable Gate Array (FPGA) chip and between an IP circuit and FPGA I/O pins. For models that do not have such an assumption, their inter-IP communication channels have severe drawbacks. Those channels do not work well with 2-D partial reconfiguration. They are not suitable for intensive data stream processing. And frequently they are very complicated to design and very expensive. To address these problems, a new chip architecture that can better support inter-IP and IP-I/O communication is proposed and a corresponding OS4RC kernel is then specified. The proposed FPGA architecture is based on an array of clusters of configurable logic blocks, with each cluster serving as a partial reconfiguration unit, and a mesh of segmented buses that provides inter-IP and IP-I/O communication channels. The proposed OS4RC kernel takes care of the scheduling, placement, and routing of circuits under the constraints of the proposed architecture. Features of the new architecture in turns reduce the kernel execution times and enable the runtime scheduling, placement and routing. The area cost and the configuration memory size of the new chip architecture are calculated and analyzed. And the efficiency of the OS4RC kernel is evaluated via simulation using three different task models

The IPS fidelity scale as a guideline to implement Supported Employment

info:eu-repo/semantics/publishe

A study on coarse-grained placement and routing for low-power FPGA architecture

制度:新 ; 報告番号:甲3603号 ; 学位の種類:博士(工学) ; 授与年月日:2012/3/15 ; 早大学位記番号:新595