Specialized processing block for implementing floating-point multiplier with subnormal operation support
First Claim
1. Circuitry for operating on floating-point numbers, each of said floating-point numbers having a mantissa and an exponent, said circuitry comprising:
- at least one operator having an operator output including mantissa data and exponent data; and
an adder having said operator output as an input, and including operating units that determine a plurality of functions of said exponent data;
wherein;
when an operation performed by said operator is a subnormal operation, said adder operates on said operator output to complete said subnormal operation based on said plurality of functions of said exponent data.
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Accused Products
Abstract
The functions available in a specialized processing block of a programmable device include floating-point operations, including support within the specialized processing block for subnormal operations. This is accomplished, in part, by borrowing an adder in the specialized processing block and using the adder to operate on output of a multiplier or other operator to compete a subnormal operation. Although the adder becomes unavailable to serve as an adder, the need to complete the operation in slower, more valuable general purpose logic is avoided. The adder and the other operator need not necessarily be located together in a specialized processing block.
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Citations
19 Claims
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1. Circuitry for operating on floating-point numbers, each of said floating-point numbers having a mantissa and an exponent, said circuitry comprising:
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at least one operator having an operator output including mantissa data and exponent data; and an adder having said operator output as an input, and including operating units that determine a plurality of functions of said exponent data;
wherein;when an operation performed by said operator is a subnormal operation, said adder operates on said operator output to complete said subnormal operation based on said plurality of functions of said exponent data. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A method of using circuitry of a programmable integrated circuit device to operate on floating-point numbers, each of said floating-point numbers having a mantissa and an exponent, and said circuitry having at least one operator that has an output including mantissa data and exponent data, and having an adder;
- said method comprising;
configuring said adder to operate on said output of said operator, including configuring operating units in said adder to determine a plurality of functions of said exponent data;
wherein;operation of said adder on said output of said operator is configured so that when an operation performed by said operator is a subnormal operation, operation of said adder on said output of said operator completes said subnormal operation based on said plurality of functions of said exponent data. - View Dependent Claims (9, 10, 11, 12, 13)
- said method comprising;
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14. A non-transitory machine readable data storage medium encoded with instructions for performing a method of using circuitry of a programmable integrated circuit device to operate on floating-point numbers, each of said floating-point numbers having a mantissa and an exponent, and said circuitry having at least one operator that has an output including mantissa data and exponent data, and having an adder;
- said instructions comprising;
instructions to configure said adder to operate on said output of said operator, including configuring operating units in said adder to determine a plurality of functions of said exponent data;
wherein;operation of said adder on said output of said operator is configured by said instructions so that when an operation performed by said operator is a subnormal operation, operation of said adder on said output of said operator completes said subnormal operation based on said plurality of functions of said exponent data. - View Dependent Claims (15, 16, 17, 18, 19)
- said instructions comprising;
Specification