Calculation of trigonometric functions in an integrated circuit device
First Claim
1. Circuitry for computing an inverse tangent function of an input, said circuitry comprising:
- circuitry for determining a relationship of said input to ‘
1’
to generate an intermediate value;
circuitry for multiplying said intermediate value by upper bits of said intermediate value to form a first product, to add said first product to ‘
1’
to form a first sum, and to invert said first sum to form a first intermediate result;
circuitry for multiplying lower bits of said intermediate value by said first intermediate result to form a second intermediate result;
look-up table circuitry for determining a third intermediate result from said upper bits of said intermediate value;
circuitry for adding said second intermediate result and said third intermediate result to form a preliminary result; and
circuitry for deriving a final result from said preliminary result based on said relationship of said input to ‘
1’
.
0 Assignments
0 Petitions
Accused Products
Abstract
Circuitry for computing a trigonometric function of an input includes circuitry for relating the input to another value to generate an intermediate value, circuitry for selecting one of the input and the intermediate value as a trigonometric input value, circuitry for determining respective initial values of a plurality of trigonometric functions for the trigonometric input value, and circuitry for deriving, based at least in part on a trigonometric identity, a final value of the first trigonometric function from the respective initial values of the plurality of trigonometric functions. The trigonometric function may be any of sine, cosine and tangent and their inverse functions. The trigonometric identities used allow a computation of a trigonometric function to be broken into pieces that either are easier to perform or can be performed more accurately.
340 Citations
36 Claims
-
1. Circuitry for computing an inverse tangent function of an input, said circuitry comprising:
-
circuitry for determining a relationship of said input to ‘
1’
to generate an intermediate value;circuitry for multiplying said intermediate value by upper bits of said intermediate value to form a first product, to add said first product to ‘
1’
to form a first sum, and to invert said first sum to form a first intermediate result;circuitry for multiplying lower bits of said intermediate value by said first intermediate result to form a second intermediate result; look-up table circuitry for determining a third intermediate result from said upper bits of said intermediate value; circuitry for adding said second intermediate result and said third intermediate result to form a preliminary result; and circuitry for deriving a final result from said preliminary result based on said relationship of said input to ‘
1’
. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
-
-
13. A method of configuring a programmable integrated circuit device as circuitry for computing an inverse tangent function of an input, said method comprising:
-
configuring logic of said programmable integrated circuit device as circuitry for determining a relationship of said input to ‘
1’
to generate an intermediate value;configuring logic of said programmable integrated circuit device as circuitry for multiplying said intermediate value by upper bits of said intermediate value to form a first product, to add said first product to ‘
1’
to form a first sum, and to invert said first sum to form a first intermediate result;configuring logic of said programmable integrated circuit device as circuitry for multiplying lower bits of said intermediate value by said first intermediate result to form a second intermediate result; configuring logic of said programmable integrated circuit device as look-up table circuitry for determining a third intermediate result from said upper bits of said intermediate value; configuring logic of said programmable integrated circuit device as circuitry for adding said second intermediate result and said third intermediate result to form a preliminary result; and configuring logic of said programmable integrated circuit device as circuitry for deriving a final result from said preliminary result based on said relationship of said input to ‘
1’
. - View Dependent Claims (14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24)
-
-
25. A non-transitory machine-readable data storage medium encoded with non-transitory machine-executable instructions for configuring a programmable integrated circuit device as circuitry for computing an inverse tangent function of an input, said instructions comprising:
-
instructions to configure logic of said programmable integrated circuit device as circuitry for determining a relationship of said input to ‘
1’
to generate an intermediate value;instructions to configure logic of said programmable integrated circuit device as circuitry for multiplying said intermediate value by upper bits of said intermediate value to form a first product, to add said first product to ‘
1’
to form a first sum, and to invert said first sum to form a first intermediate result;instructions to configure logic of said programmable integrated circuit device as circuitry for multiplying lower bits of said intermediate value by said first intermediate result to form a second intermediate result; instructions to configure logic of said programmable integrated circuit device as a look-up table for determining a third intermediate result from said upper bits of said intermediate value; instructions to configure logic of said programmable integrated circuit device as circuitry for adding said second intermediate result and said third intermediate result to form a preliminary result; and instructions to configure logic of said programmable integrated circuit device as circuitry for deriving a final result from said preliminary result based on said relationship of said input to ‘
1’
. - View Dependent Claims (26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36)
-
Specification