Method and apparatus for sticky and leading one detection
AssigneeInternational Business Machines Corporation
InventorsRoger N. Bailey, Steven M. Burchfiel, Michael P. Taborn
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Abstract
An apparatus for detecting sticky and a leading one includes first circuitry capable of detecting both sticky and a leading one. The apparatus further includes second circuitry that determines whether a sticky or a leading one detect is required. Depending upon that determination, the second circuitry controls the first circuitry to perform a sticky detection or a leading one detection. A method practiced by the apparatus includes the steps of detecting either sticky or a leading one utilizing the same circuitry, determining whether a sticky or a leading one detect is required, and controlling the circuitry in accordance with the determination of whether a sticky or a leading one detect is required.
Claims30
An apparatus for detecting sticky and a leading one of a first operand input into an execution flow that performs arithmetic operations between the first operand and a second operand input into the execution flow, the execution flow comprising arithmetic circuitry for performing arithmetic operations on the first and second operands and comparison circuitry for furnishing an output representing the comparison of the exponent of the first operand with the exponent of the second operand, comprising:
- circuitry, responsive to the of the comparison circuitry, for detecting both sticky and a leading one;
- said circuitry detecting the position of the leading one utilizing the output of the comparison circuitry when that output indicates the exponent of the first operand exceeds the exponent of the second operand;
- and
- said circuitry inputting selected bit fields of the first operand to detect sticky when the output of the comparison circuitry indicates that the exponent of the first operand is less than the exponent of the second operand.
A method for detecting sticky and a leading one of a first operand input into an execution flow that performs arithmetic operations between the first operand and a second operand input into the execution flow, the execution flow comprising arithmetic circuitry for performing arithmetic operations on the first and second operand and comparison circuitry for furnishing an output representing the comparison of the exponent of the first operand with the exponent of the second operand, comprising the steps of:
- inputting the output from the comparison circuitry into circuitry for detecting both sticky and a leading one;
- detecting the position of the leading one utilizing said circuitry and the output of the comparison circuitry when that output indicates the exponent of the first operand exceeds the exponent of the second operand;
- and
- inputting by said circuitry selected bit fields of the first operand to detect sticky when the output of the comparison circuitry indicates that the exponent of the first operand is less than the exponent of the second operand.
Dependencies are inferred from the claim text.