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Browse Prior Art Database

Logic Structure for High Frequency Data Accumulation

IP.com Disclosure Number: IPCOM000122896D
Original Publication Date: 1998-Jan-01
Included in the Prior Art Database: 2005-Apr-04
Document File: 2 page(s) / 48K

Publishing Venue

IBM

Related People

Chiang, CJ: AUTHOR [+3]

Abstract

A logic structure is disclosed for high speed data accumulation without the need of complex summation circuitry or expensive control mechanism.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 98% of the total text.

Logic Structure for High Frequency Data Accumulation

      A logic structure is disclosed for high speed data accumulation
without the need of complex summation circuitry or expensive control
mechanism.

      The disclosed accumulation structure functions mainly as a
N-operand accumulator.  However only a single 2-operand adder is
needed to implement the desired operation.  As shown in Fig. 1, the
structure consists of 3 portions: buffers (REGXs and REGYs), N-To2
carry-save pre-adder, and the adder.  The buffers are registers.  The
REGX's are clocked by the system clock.  The REGYs are clocked by the
mX clock, a  scaled down clock which is active on every (N-1)th
system clock cycle,  where N is the value used in the N-to-2
carry-save pre-addition logic.  Also clocked by the mX clock are the
accumulation register (REG-ACC) and two optional registers
(REG-OPTs).

      The implementation of a N-to2 carry-save pre-addition can be
shown with one example of 4-to-2 carry-save pre-adder logic which is
presented in Fig. 2 with associated logic tables.  The carry-save
logic is very fast and less expensive in comparison to the adder, due
to no carry-chain propagation required.  With this disclosure, the
performance of accumulation is increased in proportion to the N value
of the N-to-carry save pre-adder.  The control to the structure is
very simple and is of low cost.  A mX scaled down clock is all that
is needed.  In many systems this clock is readily avai...