Electrical computers: arithmetic processing and calculating – Electrical digital calculating computer – Particular function performed
Reexamination Certificate
1998-06-30
2001-01-23
Ngo, Chuong Dinh (Department: 2787)
Electrical computers: arithmetic processing and calculating
Electrical digital calculating computer
Particular function performed
C708S495000, C708S512000
Reexamination Certificate
active
06178435
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Technical Field
The present invention relates to a method and system for data processing in general, and in particular to a method and system for performing a numerical estimation within a data processing system. Still more particularly, the present invention relates to a method and system for performing a power of two estimation within a data processing system.
2. Description of the Prior Art
An exponential function, such as a power of two function, is commonly encountered in graphical applications. However, many processor cycles are typically required for the execution of an exponential function in a general purpose processor that does not have an exponential function in its instruction set. Even for processors having an exponential function in their instruction set, several processor cycles are required to execute an exponential function via microcode.
In view of the above, the present disclosure describes a fast implementation of a power of two function, i.e., y=2
x
, for a general purpose processor, where both the argument x and the result y are represented in a floating-point format. Without loss of generality, the floating-point format used for the purpose of illustration is the IEEE 754 format. Due to the nature of the power of two function, the practical range of values of argument x is typically restricted to a very small portion of the normal range, otherwise result y will fall outside the representable range of values.
SUMMARY OF THE INVENTION
In view of the foregoing, it is therefore an object of the present invention to provide an improved method and system for data processing.
It is another object of the present invention to provide an improved method and system for performing a numerical estimation within a data processing system.
It is yet another object of the present invention to provide an improved method and system for performing a power of two estimation within a data processing system.
In accordance with a preferred embodiment of the present invention, the floating-point number includes a sign bit, multiple exponent bits, and a mantissa having an implied one and multiple fraction bits. In order to estimate the power of two of the floating-point number, the mantissa is partitioned into an integer part and a fraction part, based on the value of the exponent bits. A floating-point result is formed by assigning the integer part of the floating-point number as an unbiased exponent of the floating-point result, and by converting the fraction part of the floating-point number via a table lookup to become a fraction part of the floating-point result.
All objects, features, and advantages of the present invention will become apparent in the following detailed written description.
REFERENCES:
patent: 4583180 (1986-04-01), Kmetz
patent: 5197024 (1993-03-01), Pickett
patent: 5365465 (1994-11-01), Larson
patent: 5524089 (1996-06-01), Takano
patent: 5570310 (1996-10-01), Smith
patent: 5652584 (1997-07-01), Yoon
Felsman Bradley Vaden Gunter & Dillon, LLP
International Business Machines - Corporation
Ngo Chuong Dinh
Salys Casimer K.
LandOfFree
Method and system for performing a power of two estimation... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method and system for performing a power of two estimation..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method and system for performing a power of two estimation... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2552229