Division with speculation of quotient digits

The speed of SRT-type dividers is mainly determined by the complexity of the quotient-digit selection, so that implementations are limited to low-radix stages. A scheme is presented in which the quotient-digit is speculated and, when this speculation is incorrect, a rollback or a partial advance is performed. This results in a division operation with a shorter cycle time and a variable number of cycles. Several designs have been realized, and a radix-64 implementation that is 30% faster than the fastest conventional implementation (radix-8) at an increase of about 45% in area per quotient bit has been obtained. A radix-16 implementation that is about 10% faster than the radix-8 conventional one, with the additional advantage of requiring about 25% less area per quotient bit, is also shownPeer ReviewedPostprint (published version

An algorithmic and architectural study on Montgomery exponentiation in RNS

The modular exponentiation on large numbers is computationally intensive. An effective way for performing this operation consists in using Montgomery exponentiation in the Residue Number System (RNS). This paper presents an algorithmic and architectural study of such exponentiation approach. From the algorithmic point of view, new and state-of-the-art opportunities that come from the reorganization of operations and precomputations are considered. From the architectural perspective, the design opportunities offered by well-known computer arithmetic techniques are studied, with the aim of developing an efficient arithmetic cell architecture. Furthermore, since the use of efficient RNS bases with a low Hamming weight are being considered with ever more interest, four additional cell architectures specifically tailored to these bases are developed and the tradeoff between benefits and drawbacks is carefully explored. An overall comparison among all the considered algorithmic approaches and cell architectures is presented, with the aim of providing the reader with an extensive overview of the Montgomery exponentiation opportunities in RNS

A NEW APPROACH OF AN ERROR DETECTING AND CORRECTING CIRCUIT BY ARITHMETIC LOGIC BLOCKS

This paper proposes a unique method of an error detection and correction (EDAC) circuit, carried out using arithmetic logic blocks. The modified logic blocks circuit and its auxiliary components are designed with Boolean and block reduction technique, which reduced one logic gate per block. The reduced logic circuits were simulated and designed using MATLAB Simulink, DSCH 2 CAD, and Microwind CAD tools. The modified, 2:1 multiplexer, demultiplexer, comparator, 1-bit adder, ALU, and error correction and detection circuit were simulated using MATLAB and Microwind. The EDAC circuit operates at a speed of 454.676 MHz and a slew rate of -2.00 which indicates excellence in high speed and low-area.

Time-Precision Flexible Arithmetic Unit

Paper submitted to the XVIII Conference on Design of Circuits and Integrated Systems (DCIS), Ciudad Real, España, 2003.A new conception of flexible calculation that allows us to adjust an operation depending on the available time computation is presented. The proposed arithmetic unit is based on this principle. It contains a control operation module that determines the process time of each calculation. The operation method design uses precalculated data stored in look-up tables, which provide, above all, quality results and systematization in the implementation of low level primitives that set parameters for the processing time. We report an evaluation of the architecture in area, delay and computation error, as well as a suitable implementation in FPGA to validate the design.This work is being backed by grant DPI2002-04434-C04-01 from the Ministerio de Ciencia y Tecnología of the Spanish Government

MIDAS, prototype Multivariate Interactive Digital Analysis System for large area earth resources surveys. Volume 1: System description

A third-generation, fast, low cost, multispectral recognition system (MIDAS) able to keep pace with the large quantity and high rates of data acquisition from large regions with present and projected sensots is described. The program can process a complete ERTS frame in forty seconds and provide a color map of sixteen constituent categories in a few minutes. A principle objective of the MIDAS program is to provide a system well interfaced with the human operator and thus to obtain large overall reductions in turn-around time and significant gains in throughput. The hardware and software generated in the overall program is described. The system contains a midi-computer to control the various high speed processing elements in the data path, a preprocessor to condition data, and a classifier which implements an all digital prototype multivariate Gaussian maximum likelihood or a Bayesian decision algorithm. Sufficient software was developed to perform signature extraction, control the preprocessor, compute classifier coefficients, control the classifier operation, operate the color display and printer, and diagnose operation