Valavan Manohararajah

Learn More
—In this paper, an iterative technology-mapping tool called IMap is presented. It supports depth-oriented (area is a secondary objective), area-oriented (depth is a secondary objective), and duplication-free mapping modes. The edge-delay model (as opposed to the more commonly used unit-delay model) is used throughout. Two new heuristics are used to obtain(More)
In this paper, we present a new linear-time retiming algorithm that produces near-optimal results. Our implementation is specically targeted at Altera's Stratix [1] FPGA-based designs, although the techniques described are general enough for any implementation medium. The algorithm is able to handle the architectural constraints of the target device,(More)
— This paper presents an overview of an industrial physical synthesis CAD flow for FPGAs. The flow provides a performance speedup of 10%–15% for most circuits, and a significant number of circuits show a speedup of 20%–180%. We describe the algorithms used to achieve this result including: incremental retiming, BDD-based resynthesis, local rewiring, and(More)
This paper studies the prediction of interconnect delay in an industrial setting. Industrial circuits and two industrial FPGA architectures were used in the study. We show that there is a large amount of inherent randomness in a state-of-the-art FPGA placement algorithm. Thus, it is impossible to predict interconnect delay with a high degree of accuracy.(More)
This paper studies the difficulty of predicting interconnect delay in an industrial setting. Fifty industrial circuits, Altera's Quartus II CAD software, and Altera's Stratix and Stratix II FPGA architectures were used in the study. We show that there is a large amount of inherent randomness in a state-of-the-art FPGA placement algorithm. Thus, it is(More)
This work explores the effect of adding a timing driven functional decomposition step to the traditional field program-mable gate array (FPGA) CAD flow. Once placement has completed, alternative decompositions of the logic on the critical path are examined for potential delay improvements. The placed circuit is then modified to use the best decompo-sitions(More)
This work explores the effect of adding a new partitioning step into the traditional complex programmable logic device (CPLD) CAD flow. A novel algorithm based on Rent's rule and simulated an-nealing partitions a design before it enters the place and route stage in CPLD CAD. The resulting partitions are then placed using an enhanced placement tool.(More)
This paper describes architectural enhancements in the Altera Stratix? 10 HyperFlex? FPGA architecture, fabricated in the Intel 14nm FinFET process. Stratix 10 includes ubiquitous flip-flops in the routing to enable a high degree of pipelining. In contrast to the earlier architectural exploration of pipelining in pass-transistor based architectures, the(More)
This work describes a new mapping technique, <i>RAM-MAP</i>, that identifies parts of circuits that can be efficiently mapped into the <i>synchronous</i> embedded memories found on field programmable gate arrays (FPGAs). Previous techniques developed for mapping into <i>asynchronous</i> embedded memories cannot be used because modern FPGAs do not have(More)
This paper presents preliminary work exploring adaptive field programmable gate arrays (AFPGAs). An AFPGA is adap-tative in the sense that the functionality of subcircuits placed on the chip can change in response to changes observed on certain control signals. We describe the high-level architecture which adds additional control logic and SRAM bits to a(More)
  • 1