Patent #3
5359551 : High speed logarithmic function generating apparatus
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INVENTORS: Pickett; Lester C., Mountain View, CA
ASSIGNEES: Log Point Technologies, Inc., Mountain View, CA
ISSUED: Oct. 25, 1994 FILED: Jan. 6 , 1993
SERIAL NUMBER: 000963 MAINT. STATUS:
INTL. CLASS (Ed. 5): G06F 001/02;
U.S. CLASS: 364/718
FIELD OF SEARCH: 364-718,722,735,748.5,750,771,753 ;
ABSTRACT: Apparatus for high speed generation of digital exponential functions in connection with a computer processor. The invention employs compact look-up tables accessed by look-up techniques and value interpolation to determine values not found in the tables. In specific embodiments, specific techniques are employed for table generation and value interpolation to attain results at desired levels of speed, precision, economy and reliability. Applications include alternatives to conventional hardware multipliers and numerical processors. Individual embodiments may be realized either directly in hardware or software. Multiple embodiments may be realized as software or hardware function libraries. Coupled multiple embodiments may be realized as general purpose hardware or software mathematical processors.
U.S. REFERENCES: Show the 3 patents that reference this one Patent Inventor Issued Title
3036774 * Brinkerhoff 5 /1962
3099742 * Byrne 7 /1963
3194951 * Schaefer 7 /1965
3402285 * Wang 9 /1968
3436533 * Moore et al. 11 /1965
4046999 Katsuoka et al. 9 /1977 Logarithmic function generating system
4062014 Rothgordt et al. 12 /1977 Natural binary to logarithmic binary conversion device with means for range selection
4077063 Lind 2 /1978 Apparatus for rapidly determining the trigonometric functions of an input angle
4078250 Windsor et al. 3 /1978 Log-antilog conversion for a digital radar system
4158889 Monden 6 /1979 Calculator for calculating ax with the base a of any positive number by calculating common logarithm of a
4164022 Rattlingourd et al. 8 /1979 Electronic digital arctangent computational apparatus
4225933 Monden 9 /1980 Exponential function computing apparatus
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EXEMPLARY CLAIM(s): Show all 13 claims
I claim:
.... (only for math heads - Mark N.)
REFERENCE TO RELATED APPLICATIONS
The present patent application is a divisional continuation of the patent application Ser. No. 07/623,238 filed Jan. 30, 1991 now U.S. Pat. No. 5,184,317, in the name of the present inventor and entitled "Method and Apparatus for Generating Mathematical Functions." Application Ser. No. 07/623,238 is a continuation of the patent application Ser. No. 07/366,376 filed Jun. 14, 1989 (now abandoned) in the name of the present inventor and also entitled "Method and Apparatus for Generating Mathematical Functions."
Reference is also made to the patent application Ser. No. 07/598,185 filed Oct. 12, 1990 in the name of the present inventor and entitled "Method and Apparatus for Exponential/Logarithmic Computation." Application Ser. No. 07/598,185 is a continuation of the application Ser. No. 07/366,080 (now abandoned) filed Jun. 14, 1989 (concurrently with the application Ser. No. 07/366,376) in the name of the present inventor and entitled "Method and Apparatus for Exponential/Logarithmic Computation."
Application Ser. No. 07/598,185 addresses the generation of fixed-point functions of generally wide range possessing derivatives of generally unrestricted magnitude with the generated functions corresponding to an implementation of general purpose floating-point operations and functions.
The present invention addresses the generation of restricted-range fixed-point mathematical functions possessing derivatives of restricted magnitude. |
