Inexact leading-one/leading-zero prediction integrated with a fl

Details Inexact leading-one/leading-zero prediction integrated with a fl Inexact leading-one/leading-zero prediction integrated with a fl

1995-10-24

1997-05-27

Mai, Tan V.

Boots, shoes, and leggings

36471504, G06F 738

Patent

active

056338198

ABSTRACT:
The sum from a floating point adder is normalized by an initial shift based on a prediction for the position of the leading one or zero in the sum. This leading-one/zero prediction is based not on the operands input to the adder, nor the result from the adder, but on the intermediate generate and propagate signals within the adder. The adder has a first stage that reduces each bit-position to a generate and a propagate signal. The adder's second stage propagates the carries in the adder using these generate and propagate signals to generate the sum. Thus the adder's first-stage logic is also used for the leading one/zero prediction, reducing cost and complexity. An ECL half-adder cell is preferably used for the adder's first stage. A zero output is added to the ECL half-adder cell at minimal cost. The shift for the leading one/zero prediction is accomplished in two stages, with a selective complement of negative sums between the two-stage shift. This allows more time for a more exact prediction after the first coarse shift. The final exact detection of the leading one is pipelined to detect the sum after the complementor but before the second stage of the shifter. This allows the final exact detection of the leading one to occur in parallel with the second stage of the shifter, reducing the delay for generating the final normalized sum by a final shifter.

REFERENCES:
patent: 5040138 (1991-08-01), Maher, III
patent: 5144570 (1992-09-01), Maher, III
patent: 5204825 (1993-04-01), Ng
patent: 5241490 (1993-08-01), Poon
patent: 5282156 (1994-01-01), Miyoshi et al.
patent: 5317527 (1994-05-01), Britton et al.
patent: 5341319 (1994-08-01), Madden et al.
patent: 5343413 (1994-08-01), Inoue
patent: 5392228 (1995-02-01), Burgess et al.
patent: 5568412 (1996-10-01), Han et al.

Affiliated with

Also associated with

Rating

Inexact leading-one/leading-zero prediction integrated with a fl does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Inexact leading-one/leading-zero prediction integrated with a fl, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Inexact leading-one/leading-zero prediction integrated with a fl will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-2333759