International Journal of Reconfigurable Computing The latest articles from Hindawi © 2017 , Hindawi Limited . All rights reserved. OpenCL-Based FPGA Accelerator for 3D FDTD with Periodic and Absorbing Boundary Conditions Sun, 16 Apr 2017 00:00:00 +0000 Finite difference time domain (FDTD) method is a very poplar way of numerically solving partial differential equations. FDTD has a low operational intensity so that the performances in CPUs and GPUs are often restricted by the memory bandwidth. Recently, deeply pipelined FPGA accelerators have shown a lot of success by exploiting streaming data flows in FDTD computation. In spite of this success, many FPGA accelerators are not suitable for real-world applications that contain complex boundary conditions. Boundary conditions break the regularity of the data flow, so that the performances are significantly reduced. This paper proposes an FPGA accelerator that computes commonly used absorbing and periodic boundary conditions in many 3D FDTD applications. Accelerator is designed using a “C-like” programming language called OpenCL (open computing language). As a result, the proposed accelerator can be customized easily by changing the software code. According to the experimental results, we achieved over 3.3 times and 1.5 times higher processing speed compared to the CPUs and GPUs, respectively. Moreover, the proposed accelerator is more than 14 times faster compared to the recently proposed FPGA accelerators that are capable of handling complex boundary conditions. Hasitha Muthumala Waidyasooriya, Tsukasa Endo, Masanori Hariyama, and Yasuo Ohtera Copyright © 2017 Hasitha Muthumala Waidyasooriya et al. All rights reserved. Efficient Realization of BCD Multipliers Using FPGAs Mon, 06 Mar 2017 09:06:56 +0000 In this paper, a novel BCD multiplier approach is proposed. The main highlight of the proposed architecture is the generation of the partial products and parallel binary operations based on 2-digit columns. 1 × 1-digit multipliers used for the partial product generation are implemented directly by 4-bit binary multipliers without any code conversion. The binary results of the 1 × 1-digit multiplications are organized according to their two-digit positions to generate the 2-digit column-based partial products. A binary-decimal compressor structure is developed and used for partial product reduction. These reduced partial products are added in optimized 6-LUT BCD adders. The parallel binary operations and the improved BCD addition result in improved performance and reduced resource usage. The proposed approach was implemented on Xilinx Virtex-5 and Virtex-6 FPGAs with emphasis on the critical path delay reduction. Pipelined BCD multipliers were implemented for 4 × 4, 8 × 8, and 16 × 16-digit multipliers. Our realizations achieve an increase in speed by up to 22% and a reduction of LUT count by up to 14% over previously reported results. Shuli Gao, Dhamin Al-Khalili, J. M. Pierre Langlois, and Noureddine Chabini Copyright © 2017 Shuli Gao et al. All rights reserved. Fuzzy Logic Based Hardware Accelerator with Partially Reconfigurable Defuzzification Stage for Image Edge Detection Wed, 01 Mar 2017 08:09:44 +0000 In this paper, the design and the implementation of a pipelined hardware accelerator based on a fuzzy logic approach for an edge detection system are presented. The fuzzy system comprises a preprocessing stage, a fuzzifier with four fuzzy inputs, an inference system with seven rules, and a defuzzification stage delivering a single crisp output, which represents the intensity value of a pixel in the output image. The hardware accelerator consists of seven stages with one clock cycle latency per stage. The defuzzification stage was implemented using three different defuzzification methods. These methods are the mean of maxima, the smallest of maxima, and the largest of maxima. The defuzzification modules are interchangeable while the system runs using partial reconfiguration design methodology. System development was carried out using Vivado High-Level Synthesis, Vivado Design Suite, Vivado Simulator, and a set of Xilinx 7000 FPGA devices. Depending upon the speed grade of the device that is employed, the system can operate at a frequency range from 83 MHz to 125 MHz. Its peak performance is up to 58 high definition frames per second. A comparison of this system’s performance and its software counterpart shows a significant speedup in the magnitude of hundred thousand times. Aous H. Kurdi, Janos L. Grantner, and Ikhlas M. Abdel-Qader Copyright © 2017 Aous H. Kurdi et al. All rights reserved. Operating System Concepts for Reconfigurable Computing: Review and Survey Wed, 30 Nov 2016 12:45:18 +0000 One of the key future challenges for reconfigurable computing is to enable higher design productivity and a more easy way to use reconfigurable computing systems for users that are unfamiliar with the underlying concepts. One way of doing this is to provide standardization and abstraction, usually supported and enforced by an operating system. This article gives historical review and a summary on ideas and key concepts to include reconfigurable computing aspects in operating systems. The article also presents an overview on published and available operating systems targeting the area of reconfigurable computing. The purpose of this article is to identify and summarize common patterns among those systems that can be seen as de facto standard. Furthermore, open problems, not covered by these already available systems, are identified. Marcel Eckert, Dominik Meyer, Jan Haase, and Bernd Klauer Copyright © 2016 Marcel Eckert et al. All rights reserved. Comment on “High Efficiency Generalized Parallel Counters for Look-Up Table Based FPGAs” Wed, 14 Sep 2016 09:53:28 +0000 This brief points out some problems when mapping the optimized GPCs using the heuristic of the paper above. A thorough analysis revealed that a significant number of additional LUTs are required to route the signals when mapping the optimized designs on current FPGAs. Taking these resources into account, the optimized GPCs require at least the same resources as previous state of the art. Martin Kumm and Peter Zipf Copyright © 2016 Martin Kumm and Peter Zipf. All rights reserved. An Efficient FPGA Implementation of Optimized Anisotropic Diffusion Filtering of Images Mon, 18 Jul 2016 16:08:39 +0000 Digital image processing is an exciting area of research with a variety of applications including medical, surveillance security systems, defence, and space applications. Noise removal as a preprocessing step helps to improve the performance of the signal processing algorithms, thereby enhancing image quality. Anisotropic diffusion filtering proposed by Perona and Malik can be used as an edge-preserving smoother, removing high-frequency components of images without blurring their edges. In this paper, we present the FPGA implementation of an edge-preserving anisotropic diffusion filter for digital images. The designed architecture completely replaced the convolution operation and implemented the same using simple arithmetic subtraction of the neighboring intensities within a kernel, preceded by multiple operations in parallel within the kernel. To improve the image reconstruction quality, the diffusion coefficient parameter, responsible for controlling the filtering process, has been properly analyzed. Its signal behavior has been studied by subsequently scaling and differentiating the signal. The hardware implementation of the proposed design shows better performance in terms of reconstruction quality and accelerated performance with respect to its software implementation. It also reduces computation, power consumption, and resource utilization with respect to other related works. Chandrajit Pal, Avik Kotal, Asit Samanta, Amlan Chakrabarti, and Ranjan Ghosh Copyright © 2016 Chandrajit Pal et al. All rights reserved. FPGA Based High Speed SPA Resistant Elliptic Curve Scalar Multiplier Architecture Sun, 10 Jul 2016 06:38:44 +0000 The higher computational complexity of an elliptic curve scalar point multiplication operation limits its implementation on general purpose processors. Dedicated hardware architectures are essential to reduce the computational time, which results in a substantial increase in the performance of associated cryptographic protocols. This paper presents a unified architecture to compute modular addition, subtraction, and multiplication operations over a finite field of large prime characteristic . Subsequently, dual instances of the unified architecture are utilized in the design of high speed elliptic curve scalar multiplier architecture. The proposed architecture is synthesized and implemented on several different Xilinx FPGA platforms for different field sizes. The proposed design computes a 192-bit elliptic curve scalar multiplication in 2.3 ms on Virtex-4 FPGA platform. It is 34 faster and requires 40 fewer clock cycles for elliptic curve scalar multiplication and consumes considerable fewer FPGA slices as compared to the other existing designs. The proposed design is also resistant to the timing and simple power analysis (SPA) attacks; therefore it is a good choice in the construction of fast and secure elliptic curve based cryptographic protocols. Khalid Javeed and Xiaojun Wang Copyright © 2016 Khalid Javeed and Xiaojun Wang. All rights reserved. An Accelerating Solution for -Body MOND Simulation with FPGA-SoC Sun, 12 Jun 2016 10:46:16 +0000 As a modified-gravity proposal to handle the dark matter problem on galactic scales, Modified Newtonian Dynamics (MOND) has shown a great success. However, the -body MOND simulation is quite challenged by its computation complexity, which appeals to acceleration of the simulation calculation. In this paper, we present a highly integrated accelerating solution for -body MOND simulations. By using the FPGA-SoC, which integrates both FPGA and SoC (system on chip) in one chip, our solution exhibits potentials for better performance, higher integration, and lower power consumption. To handle the calculation bottleneck of potential summation, on one hand, we develop a strategy to simplify the pipeline, in which the square calculation task is conducted by the DSP48E1 of Xilinx 7 series FPGAs, so as to reduce the logic resource utilization of each pipeline; on the other hand, advantages of particle-mesh scheme are taken to overcome the bottleneck on bandwidth. Our experiment results show that 2 more pipelines can be integrated in Zynq-7020 FPGA-SoC with the simplified pipeline, and the bandwidth requirement is reduced significantly. Furthermore, our accelerating solution has a full range of advantages over different processors. Compared with GPU, our work is about 10 times better in performance per watt and 50% better in performance per cost. Bo Peng, Tianqi Wang, Xi Jin, and Chuanjun Wang Copyright © 2016 Bo Peng et al. All rights reserved. An FPGA-Based Quantum Computing Emulation Framework Based on Serial-Parallel Architecture Thu, 07 Apr 2016 07:59:21 +0000 Hardware emulation of quantum systems can mimic more efficiently the parallel behaviour of quantum computations, thus allowing higher processing speed-up than software simulations. In this paper, an efficient hardware emulation method that employs a serial-parallel hardware architecture targeted for field programmable gate array (FPGA) is proposed. Quantum Fourier transform and Grover’s search are chosen as case studies in this work since they are the core of many useful quantum algorithms. Experimental work shows that, with the proposed emulation architecture, a linear reduction in resource utilization is attained against the pipeline implementations proposed in prior works. The proposed work contributes to the formulation of a proof-of-concept baseline FPGA emulation framework with optimization on datapath designs that can be extended to emulate practical large-scale quantum circuits. Y. H. Lee, M. Khalil-Hani, and M. N. Marsono Copyright © 2016 Y. H. Lee et al. All rights reserved. FPGA-Based Real-Time Moving Target Detection System for Unmanned Aerial Vehicle Application Mon, 04 Apr 2016 11:35:00 +0000 Moving target detection is the most common task for Unmanned Aerial Vehicle (UAV) to find and track object of interest from a bird’s eye view in mobile aerial surveillance for civilian applications such as search and rescue operation. The complex detection algorithm can be implemented in a real-time embedded system using Field Programmable Gate Array (FPGA). This paper presents the development of real-time moving target detection System-on-Chip (SoC) using FPGA for deployment on a UAV. The detection algorithm utilizes area-based image registration technique which includes motion estimation and object segmentation processes. The moving target detection system has been prototyped on a low-cost Terasic DE2-115 board mounted with TRDB-D5M camera. The system consists of Nios II processor and stream-oriented dedicated hardware accelerators running at 100 MHz clock rate, achieving 30-frame per second processing speed for 640 × 480 pixels’ resolution greyscale videos. Jia Wei Tang, Nasir Shaikh-Husin, Usman Ullah Sheikh, and M. N. Marsono Copyright © 2016 Jia Wei Tang et al. All rights reserved. Modules for Pipelined Mixed Radix FFT Processors Tue, 22 Mar 2016 10:44:59 +0000 A set of soft IP cores for the Winograd -point fast Fourier transform (FFT) is considered. The cores are designed by the method of spatial SDF mapping into the hardware, which provides the minimized hardware volume at the cost of slowdown of the algorithm by times. Their clock frequency is equal to the data sampling frequency. The cores are intended for the high-speed pipelined FFT processors, which are implemented in FPGA. Anatolij Sergiyenko and Anastasia Serhienko Copyright © 2016 Anatolij Sergiyenko and Anastasia Serhienko. All rights reserved. How to Efficiently Reconfigure Tunable Lookup Tables for Dynamic Circuit Specialization Mon, 21 Mar 2016 07:22:53 +0000 Dynamic Circuit Specialization is used to optimize the implementation of a parameterized application on an FPGA. Instead of implementing the parameters as regular inputs, in the DCS approach these inputs are implemented as constants. When the parameter values change, the design is reoptimized for the new constant values by reconfiguring the FPGA. This allows faster and more resource-efficient implementation but investigations have shown that reconfiguration time is the major limitation for DCS implementation on Xilinx FPGAs. The limitation arises from the use of inefficient reconfiguration methods in conventional DCS implementation. To address this issue, we propose different approaches to reduce the reconfiguration time drastically and improve the reconfiguration speed. In this context, this paper presents the use of custom reconfiguration controllers and custom reconfiguration software drivers, along with placement constraints to shorten the reconfiguration time. Our results show an improvement in the reconfiguration speed by at least a factor 14 by using Xilinx reconfiguration controller along with placement constraints. However, the improvement can go up to a factor 40 with the combination of a custom reconfiguration controller, custom software drivers, and placement constraints. We also observe depreciation in the system’s performance by at least 6% due to placement constraints. Amit Kulkarni and Dirk Stroobandt Copyright © 2016 Amit Kulkarni and Dirk Stroobandt. All rights reserved. On-Chip Reconfigurable Hardware Accelerators for Popcount Computations Thu, 10 Mar 2016 14:32:46 +0000 Popcount computations are widely used in such areas as combinatorial search, data processing, statistical analysis, and bio- and chemical informatics. In many practical problems the size of initial data is very large and increase in throughput is important. The paper suggests two types of hardware accelerators that are (1) designed in FPGAs and (2) implemented in Zynq-7000 all programmable systems-on-chip with partitioning of algorithms that use popcounts between software of ARM Cortex-A9 processing system and advanced programmable logic. A three-level system architecture that includes a general-purpose computer, the problem-specific ARM, and reconfigurable hardware is then proposed. The results of experiments and comparisons with existing benchmarks demonstrate that although throughput of popcount computations is increased in FPGA-based designs interacting with general-purpose computers, communication overheads (in experiments with PCI express) are significant and actual advantages can be gained if not only popcount but also other types of relevant computations are implemented in hardware. The comparison of software/hardware designs for Zynq-7000 all programmable systems-on-chip with pure software implementations in the same Zynq-7000 devices demonstrates increase in performance by a factor ranging from 5 to 19 (taking into account all the involved communication overheads between the programmable logic and the processing systems). Valery Sklyarov, Iouliia Skliarova, and João Silva Copyright © 2016 Valery Sklyarov et al. All rights reserved. An Efficient Evolutionary Task Scheduling/Binding Framework for Reconfigurable Systems Mon, 07 Mar 2016 12:06:42 +0000 Several embedded application domains for reconfigurable systems tend to combine frequent changes with high performance demands of their workloads such as image processing, wearable computing, and network processors. Time multiplexing of reconfigurable hardware resources raises a number of new issues, ranging from run-time systems to complex programming models that usually form a reconfigurable operating system (ROS). In this paper, an efficient ROS framework that aids the designer from the early design stages all the way to the actual hardware implementation is proposed and implemented. An efficient reconfigurable platform is implemented along with novel placement/scheduling algorithms. The proposed algorithms tend to reuse hardware tasks to reduce reconfiguration overhead, migrate tasks between software and hardware to efficiently utilize resources, and reduce computation time. A supporting framework for efficient mapping of execution units to task graphs in a run-time reconfigurable system is also designed. The framework utilizes an Island Based Genetic Algorithm flow that optimizes several objectives including performance, area, and power consumption. The proposed Island Based GA framework achieves on average 55.2% improvement over a single-GA implementation and an 80.7% improvement over a baseline random allocation and binding approach. A. Al-Wattar, S. Areibi, and G. Grewal Copyright © 2016 A. Al-Wattar et al. All rights reserved. XOR-FREE Implementation of Convolutional Encoder for Reconfigurable Hardware Tue, 23 Feb 2016 13:25:36 +0000 This paper presents a novel XOR-FREE algorithm to implement the convolutional encoder using reconfigurable hardware. The approach completely removes the XOR processing of a chosen nonsystematic, feedforward generator polynomial of larger constraint length. The hardware (HW) implementation of new architecture uses Lookup Table (LUT) for storing the parity bits. The design implements architectural reconfigurability by modifying the generator polynomial of the same constraint length and code rate to reduce the design complexity. The proposed architecture reduces the dynamic power up to 30% and improves the hardware cost and propagation delay up to 20% and 32%, respectively. The performance of the proposed architecture is validated in MATLAB Simulink and tested on Zynq-7 series FPGA. Gaurav Purohit, Kota Solomon Raju, and Vinod Kumar Chaubey Copyright © 2016 Gaurav Purohit et al. All rights reserved. A Scalable Unsegmented Multiport Memory for FPGA-Based Systems Thu, 31 Dec 2015 13:20:44 +0000 On-chip multiport memory cores are crucial primitives for many modern high-performance reconfigurable architectures and multicore systems. Previous approaches for scaling memory cores come at the cost of operating frequency, communication overhead, and logic resources without increasing the storage capacity of the memory. In this paper, we present two approaches for designing multiport memory cores that are suitable for reconfigurable accelerators with substantial on-chip memory or complex communication. Our design approaches tackle these challenges by banking RAM blocks and utilizing interconnect networks which allows scaling without sacrificing logic resources. With banking, memory congestion is unavoidable and we evaluate our multiport memory cores under different memory access patterns to gain insights about different design trade-offs. We demonstrate our implementation with up to 256 memory ports using a Xilinx Virtex-7 FPGA. Our experimental results report high throughput memories with resource usage that scales with the number of ports. Kevin R. Townsend, Osama G. Attia, Phillip H. Jones, and Joseph Zambreno Copyright © 2015 Kevin R. Townsend et al. All rights reserved. Exploring Trade-Offs between Specialized Dataflow Kernels and a Reusable Overlay in a Stereo Matching Case Study Wed, 30 Dec 2015 11:48:26 +0000 FPGAs are known to permit huge gains in performance and efficiency for suitable applications but still require reduced design efforts and shorter development cycles for wider adoption. In this work, we compare the resulting performance of two design concepts that in different ways promise such increased productivity. As common starting point, we employ a kernel-centric design approach, where computational hotspots in an application are identified and individually accelerated on FPGA. By means of a complex stereo matching application, we evaluate two fundamentally different design philosophies and approaches for implementing the required kernels on FPGAs. In the first implementation approach, we designed individually specialized data flow kernels in a spatial programming language for a Maxeler FPGA platform; in the alternative design approach, we target a vector coprocessor with large vector lengths, which is implemented as a form of programmable overlay on the application FPGAs of a Convey HC-1. We assess both approaches in terms of overall system performance, raw kernel performance, and performance relative to invested resources. After compensating for the effects of the underlying hardware platforms, the specialized dataflow kernels on the Maxeler platform are around 3x faster than kernels executing on the Convey vector coprocessor. In our concrete scenario, due to trade-offs between reconfiguration overheads and exposed parallelism, the advantage of specialized dataflow kernels is reduced to around 2.5x. Tobias Kenter, Henning Schmitz, and Christian Plessl Copyright © 2015 Tobias Kenter et al. All rights reserved. AC_ICAP: A Flexible High Speed ICAP Controller Thu, 17 Dec 2015 09:49:10 +0000 The Internal Configuration Access Port (ICAP) is the core component of any dynamic partial reconfigurable system implemented in Xilinx SRAM-based Field Programmable Gate Arrays (FPGAs). We developed a new high speed ICAP controller, named AC_ICAP, completely implemented in hardware. In addition to similar solutions to accelerate the management of partial bitstreams and frames, AC_ICAP also supports run-time reconfiguration of LUTs without requiring precomputed partial bitstreams. This last characteristic was possible by performing reverse engineering on the bitstream. Besides, we adapted this hardware-based solution to provide IP cores accessible from the MicroBlaze processor. To this end, the controller was extended and three versions were implemented to evaluate its performance when connected to Peripheral Local Bus (PLB), Fast Simplex Link (FSL), and AXI interfaces of the processor. In consequence, the controller can exploit the flexibility that the processor offers but taking advantage of the hardware speed-up. It was implemented in both Virtex-5 and Kintex7 FPGAs. Results of reconfiguration time showed that run-time reconfiguration of single LUTs in Virtex-5 devices was performed in less than 5 μs which implies a speed-up of more than 380x compared to the Xilinx XPS_HWICAP controller. Luis Andres Cardona and Carles Ferrer Copyright © 2015 Luis Andres Cardona and Carles Ferrer. All rights reserved. Dynamic Task Distribution Model for On-Chip Reconfigurable High Speed Computing System Thu, 10 Dec 2015 07:08:20 +0000 Modern embedded systems are being modeled as Reconfigurable High Speed Computing System (RHSCS) where Reconfigurable Hardware, that is, Field Programmable Gate Array (FPGA), and softcore processors configured on FPGA act as computing elements. As system complexity increases, efficient task distribution methodologies are essential to obtain high performance. A dynamic task distribution methodology based on Minimum Laxity First (MLF) policy (DTD-MLF) distributes the tasks of an application dynamically onto RHSCS and utilizes available RHSCS resources effectively. The DTD-MLF methodology takes the advantage of runtime design parameters of an application represented as DAG and considers the attributes of tasks in DAG and computing resources to distribute the tasks of an application onto RHSCS. In this paper, we have described the DTD-MLF model and verified its effectiveness by distributing some of real life benchmark applications onto RHSCS configured on Virtex-5 FPGA device. Some benchmark applications are represented as DAG and are distributed to the resources of RHSCS based on DTD-MLF model. The performance of the MLF based dynamic task distribution methodology is compared with static task distribution methodology. The comparison shows that the dynamic task distribution model with MLF criteria outperforms the static task distribution techniques in terms of schedule length and effective utilization of available RHSCS resources. Mahendra Vucha and Arvind Rajawat Copyright © 2015 Mahendra Vucha and Arvind Rajawat. All rights reserved. An Improved Diffusion Based Placement Algorithm for Reducing Interconnect Demand in Congested Regions of FPGAs Wed, 11 Nov 2015 12:47:11 +0000 An FPGA has a finite routing capacity due to which a fair number of highly dense circuits fail to map on slightly underresourced architecture. The high-interconnect demand in the congested regions is not met by the available resources as a result of which the circuit becomes unroutable for that particular architecture. In this paper, we present a new placement approach which is based on a natural process called diffusion. Our placer attempts to minimize the routing congestion by evenly disseminating the interconnect demand across an FPGA chip. For the 20 MCNC benchmark circuits, our algorithm reduced the channel width for 15 circuits. The results showed on average ~33% reduction in standard deviation of interconnect usage at an expense of an average ~13% penalty on critical path delay. Maximum channel width gain of ~33% was also observed. Ali Asghar and Husain Parvez Copyright © 2015 Ali Asghar and Husain Parvez. All rights reserved. High Efficiency Generalized Parallel Counters for Look-Up Table Based FPGAs Mon, 19 Oct 2015 09:12:02 +0000 Generalized parallel counters (GPCs) are used in constructing high speed compressor trees. Prior work has focused on utilizing the fast carry chain and mapping the logic onto Look-Up Tables (LUTs). This mapping is not optimal in the sense that the LUT fabric is not fully utilized. This results in low efficiency GPCs. In this work, we present a heuristic that efficiently maps the GPC logic onto the LUT fabric. We have used our heuristic on various GPCs and have achieved an improvement in efficiency ranging from 33% to 100% in most of the cases. Experimental results using Xilinx 5th-, 6th-, and 7th-generation FPGAs and Stratix IV and V devices from Altera show a considerable reduction in resources utilization and dynamic power dissipation, for almost the same critical path delay. We have also implemented GPC-based FIR filters on 7th-generation Xilinx FPGAs using our proposed heuristic and compared their performance against conventional implementations. Implementations based on our heuristic show improved performance. Comparisons are also made against filters based on integrated DSP blocks and inherent IP cores from Xilinx. The results show that the proposed heuristic provides performance that is comparable to the structures based on these specialized resources. Burhan Khurshid and Roohie Naaz Mir Copyright © 2015 Burhan Khurshid and Roohie Naaz Mir. All rights reserved. Leakage Immune Modified Pass Transistor Based 8T SRAM Cell in Subthreshold Region Wed, 30 Sep 2015 07:11:37 +0000 The paper presents a novel 8T SRAM cell with access pass gates replaced with modified PMOS pass transistor logic. In comparison to 6T SRAM cell, the proposed cell achieves 3.5x higher read SNM and 2.4x higher write SNM with 16.6% improved SINM (static current noise margin) distribution at the expense of 7x lower WTI (write trip current) at 0.4 V power supply voltage, while maintaining similar stability in hold mode. The proposed 8T SRAM cell shows improvements in terms of 7.735x narrower spread in average standby power, 2.61x less in average (write access time), and 1.07x less in average (read access time) at supply voltage varying from 0.3 V to 0.5 V as compared to 6T SRAM equivalent at 45 nm technology node. Thus, comparative analysis shows that the proposed design has a significant improvement, thereby achieving high cell stability at 45 nm technology node. Priya Gupta, Anu Gupta, and Abhijit Asati Copyright © 2015 Priya Gupta et al. All rights reserved. Core-Level Modeling and Frequency Prediction for DSP Applications on FPGAs Thu, 03 Sep 2015 10:20:57 +0000 Field-programmable gate arrays (FPGAs) provide a promising technology that can improve performance of many high-performance computing and embedded applications. However, unlike software design tools, the relatively immature state of FPGA tools significantly limits productivity and consequently prevents widespread adoption of the technology. For example, the lengthy design-translate-execute (DTE) process often must be iterated to meet the application requirements. Previous works have enabled model-based, design-space exploration to reduce DTE iterations but are limited by a lack of accurate model-based prediction of key design parameters, the most important of which is clock frequency. In this paper, we present a core-level modeling and design (CMD) methodology that enables modeling of FPGA applications at an abstract level and yet produces accurate predictions of parameters such as clock frequency, resource utilization (i.e., area), and latency. We evaluate CMD’s prediction methods using several high-performance DSP applications on various families of FPGAs and show an average clock-frequency prediction error of 3.6%, with a worst-case error of 20.4%, compared to the best of existing high-level prediction methods, 13.9% average error with 48.2% worst-case error. We also demonstrate how such prediction enables accurate design-space exploration without coding in a hardware-description language (HDL), significantly reducing the total design time. Gongyu Wang, Greg Stitt, Herman Lam, and Alan George Copyright © 2015 Gongyu Wang et al. All rights reserved. Representing Tactics for Fault Recovery: A Reconfigurable, Modular, and Hierarchical Approach Tue, 16 Jun 2015 10:02:34 +0000 We show the advantages of modular and hierarchical design in obtaining fault-tolerant software. Modularity enables the identification of faulty software units simplifying key operations, like software removal and replacement. We describe three approaches to repair faulty software based on replication, namely, Passive Replication, N-Version Replication, and Active Replication, based on modular components. We show that the key construct to represent these tactics is the ability to make ad hoc changes in software topologies. We consider hierarchical mobility as a useful operation to introduce new software units for replacing faulty ones. For illustration purposes, we use connecton, a hierarchical, modular, and self-modifying software specification formalism, and its implementation in the Desmos framework. Fernando J. Barros Copyright © 2015 Fernando J. Barros. All rights reserved. Low Latency Network-on-Chip Router Microarchitecture Using Request Masking Technique Sun, 15 Mar 2015 08:48:59 +0000 Network-on-Chip (NoC) is fast emerging as an on-chip communication alternative for many-core System-on-Chips (SoCs). However, designing a high performance low latency NoC with low area overhead has remained a challenge. In this paper, we present a two-clock-cycle latency NoC microarchitecture. An efficient request masking technique is proposed to combine virtual channel (VC) allocation with switch allocation nonspeculatively. Our proposed NoC architecture is optimized in terms of area overhead, operating frequency, and quality-of-service (QoS). We evaluate our NoC against CONNECT, an open source low latency NoC design targeted for field-programmable gate array (FPGA). The experimental results on several FPGA devices show that our NoC router outperforms CONNECT with 50% reduction of logic cells (LCs) utilization, while it works with 100% and 35%~20% higher operating frequency compared to the one- and two-clock-cycle latency CONNECT NoC routers, respectively. Moreover, the proposed NoC router achieves 2.3 times better performance compared to CONNECT. Alireza Monemi, Chia Yee Ooi, and Muhammad Nadzir Marsono Copyright © 2015 Alireza Monemi et al. All rights reserved. Optimization of Lookup Schemes for Flow-Based Packet Classification on FPGAs Sun, 08 Mar 2015 11:25:26 +0000 Packet classification has become a key processing function to enable future flow-based networking schemes. As network capacity increases and new services are deployed, both high throughput and reconfigurability are required for packet classification architectures. FPGA technology can provide the best trade-off among them. However, to date, lookup stages have been mostly developed as independent schemes from the classification stage, which makes their efficient integration on FPGAs difficult. In this context, we propose a new interpretation of the lookup problem in the general context of packet classification, which enables comparing existing lookup schemes on a common basis. From this analysis, we recognize new opportunities for optimization of lookup schemes and their associated classification schemes on FPGA. In particular, we focus on the most appropriate candidate for future networking needs and propose optimizations for it. To validate our analysis, we provide estimation and implementation results for typical lookup architectures on FPGA and observe their convenience for different lookup and classification cases, demonstrating the benefits of our proposed optimization. Carlos A. Zerbini and Jorge M. Finochietto Copyright © 2015 Carlos A. Zerbini and Jorge M. Finochietto. All rights reserved. Using Genetic Algorithms for Hardware Core Placement and Mapping in NoC-Based Reconfigurable Systems Mon, 02 Feb 2015 13:38:30 +0000 Mapping of cores has been an important activity in NoC-based system design aimed to find the best topological location onto the NoC, such that the metrics of interest can be greatly optimized. In the last years, partial reconfigurable systems (PRSs) have included Networks-on-Chips (NoCs) as their communication structure, adding complexity to the problem of mapping. Several works have proposed specific and robust NoC architectures for PRSs, forming indirect and irregular networks, in which cases the mapping and placement problems must be treated altogether. The placement deals with the physical positioning of those cores inside the reconfigurable device. Up to now, to the best of our knowledge, the mapping-placement problem for those kinds of architectures has not been addressed yet. In this work, the problem formalization for the design-time hardware core placement and mapping in PRS-NoCs is proposed and methodologies for solving it with genetic algorithms (GAs) are presented. Several GA crossovers and methodologies are compared for obtaining the best solution. Results have shown that best GA solution obtained, in average, communication costs with 4% of penalty when compared with global minimum cost, obtained in a semiexhaustive approach. In addition, the algorithm presents low execution times. Jonas Gomes Filho, Marius Strum, and Wang Jiang Chau Copyright © 2015 Jonas Gomes Filho et al. All rights reserved. Scalable Fixed Point QRD Core Using Dynamic Partial Reconfiguration Sun, 14 Dec 2014 00:10:17 +0000 A Givens rotation based scalable QRD core which utilizes an efficient pipelined and unfolded 2D multiply and accumulate (MAC) based systolic array architecture with dynamic partial reconfiguration (DPR) capability is proposed. The square root and inverse square root operations in the Givens rotation algorithm are handled using a modified look-up table (LUT) based Newton-Raphson method, thereby reducing the area by 71% and latency by 50% while operating at a frequency 49% higher than the existing boundary cell architectures. The proposed architecture is implemented on Xilinx Virtex-6 FPGA for any real matrices of size , where and by dynamically inserting or removing the partial modules. The evaluation results demonstrate a significant reduction in latency, area, and power as compared to other existing architectures. The functionality of the proposed core is evaluated for a variable length adaptive equalizer. Gayathri R. Prabhu, Bibin Johnson, and J. Sheeba Rani Copyright © 2014 Gayathri R. Prabhu et al. All rights reserved. Multi-Softcore Architecture on FPGA Thu, 27 Nov 2014 06:22:28 +0000 To meet the high performance demands of embedded multimedia applications, embedded systems are integrating multiple processing units. However, they are mostly based on custom-logic design methodology. Designing parallel multicore systems using available standards intellectual properties yet maintaining high performance is also a challenging issue. Softcore processors and field programmable gate arrays (FPGAs) are a cheap and fast option to develop and test such systems. This paper describes a FPGA-based design methodology to implement a rapid prototype of parametric multicore systems. A study of the viability of making the SoC using the NIOS II soft-processor core from Altera is also presented. The NIOS II features a general-purpose RISC CPU architecture designed to address a wide range of applications. The performance of the implemented architecture is discussed, and also some parallel applications are used for testing speedup and efficiency of the system. Experimental results demonstrate the performance of the proposed multicore system, which achieves better speedup than the GPU (29.5% faster for the FIR filter and 23.6% faster for the matrix-matrix multiplication). Mouna Baklouti and Mohamed Abid Copyright © 2014 Mouna Baklouti and Mohamed Abid. All rights reserved. Low-Cost Fault Tolerant Methodology for Real Time MPSoC Based Embedded System Wed, 19 Nov 2014 08:50:55 +0000 We are proposing a design methodology for a fault tolerant homogeneous MPSoC having additional design objectives that include low hardware overhead and performance. We have implemented three different FT methodologies on MPSoCs and compared them against the defined constraints. The comparison of these FT methodologies is carried out by modelling their architectures in VHDL-RTL, on Spartan 3 FPGA. The results obtained through simulations helped us to identify the most relevant scheme in terms of the given design constraints. Mohsin Amin, Muhammad Shakir, Aqib Javed, Muhammad Hassan, and Syed Ali Raza Copyright © 2014 Mohsin Amin et al. All rights reserved.