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Publicações

Publicações por João Paiva Cardoso

2009

AUTOMATIC GENERATION OF FPGA HARDWARE ACCELERATORS USING A DOMAIN SPECIFIC LANGUAGE

Autores
Menotti, R; Cardoso, JMP; Fernandes, MM; Marques, E;

Publicação
FPL: 2009 INTERNATIONAL CONFERENCE ON FIELD PROGRAMMABLE LOGIC AND APPLICATIONS

Abstract
This paper describes an alternative approach to direct mapping loops described in high-level languages onto FPGAs. Different from other approaches, this technique does not inherit from software pipelining techniques. The control is distributed over operations, thus a finite state machine is not necessary to control the order of operations, allowing efficient hardware implementations. The specification of a hardware block is done by means of LALP, a domain specific language specially designed to help the application of the techniques. While the language syntax resembles C, it contains certain constructs that allow programmer interventions to enforce or relax data dependences as needed, and so optimize the performance of the generated hardware blocks.

2008

Combining Rewriting-Logic, Architecture Generation, and Simulation to Exploit Coarse-Grained Reconfigurable Architectures

Autores
Morra, C; Bispo, J; Cardoso, JMP; Becker, J;

Publicação
PROCEEDINGS OF THE SIXTEENTH IEEE SYMPOSIUM ON FIELD-PROGRAMMABLE CUSTOM COMPUTING MACHINES

Abstract

2008

Retargeting, evaluating, and generating reconfigurable array-based architectures

Autores
Morra, C; Cardoso, JMP; Bispo, J; Becker, J;

Publicação
2008 SYMPOSIUM ON APPLICATION SPECIFIC PROCESSORS

Abstract
Coarse-grained reconfigurable architectures have proven their value as programmable accelerators for general purpose processors. For early evaluation of those architectures, we need an approach able to exploit and retarget different Processing Elements (PEs) while maintaining the same compilation flow. Bearing in mind those aspects, this paper describes an approach able to map, evaluate and generate reconfigurable architectures based on an array of PEs. We use Rewriting Logic to map computations described by imperative programming languages to the PEs of the target architecture, a VHDL generation step to prototype the architectures being evaluated, and a clock cycle-based simulator to achieve first assessments about the performance of those architectures. In order to show the potential of our approach, we present results of 1-D coarse-grained reconfigurable arrays as accelerator softcores implemented in an FPGA, and the effects of different PE's structures and complexities.

2007

Aggressive loop pipelining for reconfigurable architectures

Autores
Menotti, R; Marques, E; Cardoso, JMP;

Publicação
2007 INTERNATIONAL CONFERENCE ON FIELD PROGRAMMABLE LOGIC AND APPLICATIONS, PROCEEDINGS, VOLS 1 AND 2

Abstract

2007

On adapting power estimation models for embedded soft-core processors

Autores
de Holanda, JA; Assumpcao, J; Wolf, DE; Marques, E; Cardoso, JMP;

Publicação
2007 INTERNATIONAL SYMPOSIUM ON INDUSTRIAL EMBEDDED SYSTEMS

Abstract
The increasing use of battery-powered embedded systems has motivated the development of power consumption models in order to help designers to build low-power systems. Due to the configurability features of FPGAs, the adoption of systems containing one or more soft-core processors on a single chip is becoming more and more attractive. This paper presents an adaptation of the instruction-level power estimation model to soft-core processors implemented in FPGAs. This model allowed to estimate the power dissipated in eleven test applications with a maximum error of 4.78%. The Ongoing work includes efforts towards a software power estimation model for multi-core systems embedded in a single FPGA device.

2007

An FPGA implementation for a kalman filter with application to mobile robotics

Autores
Bonato, V; Peron, R; Wolf, DF; de Holanda, JAM; Marques, E; Cardoso, JMP;

Publicação
2007 INTERNATIONAL SYMPOSIUM ON INDUSTRIAL EMBEDDED SYSTEMS

Abstract
The problem of simultaneous localization and mapping has been studied by the mobile robotics scientific community over the last two decades. Most solutions for this problem are based on probabilistic theory in order to represent the uncertainty in robot perception and action. One of the most efficient probabilistic methods is the Extended Kalman Filter (EKF). However, the EKF demands a considerable amount of computing power and is usually processed by high-end laptops coupled to the robots. In this work, we present an implementation of the EKF targeting an embedded system based on an FPGA device. In order to improve performance, our approach combines a softcore processor with customized hardware. We present experiments with four different FPGA implementations, being the first purely based on software, the second using custom instruction logic directly connected to the processor's ALU, the third using hardware accelerators connected to the processor's data bus, and finally the fourth combining those two hardware/software solutions. For the experiments conducted, the results obtained with a small addition of hardware resources permitted to increase from 2x to 4x the performance of the global system.

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