Direct Decimal Number Tripling in Binary Coded Adders
AssigneeInternational Business Machines Corporation
InventorsMark Alan Erle, Brian John Hickmann
Life of this patent
Estimating the term…
Abstract
The digital propagate, digit generate, sum+0, and sum+1 terms used in typical carry-propagate adders are generated directly off the multiplicand. During the direct generation, the logic takes into account that each digit will be tripled and if each digit's next less significant digit is greater than 4. Using this technique, the generation of the multiplicand is significantly faster and uses less circuitry.
Claims20
A method for multiplying a multibit binary multiplicand and a multibit binary multiplier using a binary adder, comprising the steps of:
- generating a required multiple of the multiplicand directly from the multiplicand by determining for each decimal digit represented by the binary number greater than 4 and determining for each said binary number the digit generate, digit propagate, sum+0, and sum+1 values based on whether the next less significant digit represents a decimal digit that is greater or less than 4;
- and
- generating the required multiple of the multiplicand using the determined levels.
Software in a tangible medium for generating multiples of a multibit binary multiplicand for multiplying this multibit binary multiplicand by a multibit binary multiplier using a binary adder, comprising:
- computer code for generating a required multiple of the multiplicand directly from the multiplicand by determining for each decimal digit represented by the binary number greater than 4 and determining for each said binary number the digit generate, digit propagate, sum+0, and sum+1 values based on whether the next less significant digit represents a decimal digit that is greater or less than 4;
- and
- computer code for generating the required multiple of the multiplicand using the determined levels.
A multiplier for multiplying a multibit binary multiplicand by a multibit binary multiplier using a binary adder, being characterized by:
- apparatus for generating a required multiple of the multiplicand directly from the multiplicand by first determining for each decimal digit represented by the binary number greater than 4 and then determining for each said binary number the digit generate, digit propagate, sum+0, and sum+1 values based on whether the next less significant digit represents a decimal digit that is greater or less than 4;
- and
- generating the required multiple of the multiplicand using the determined levels.
Dependencies are inferred from the claim text.