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Offline Residue Checking for a Floating-Point Arithmetic Unit Executing Overlapped Operations

IP.com Disclosure Number: IPCOM000040534D
Original Publication Date: 1987-Nov-01
Included in the Prior Art Database: 2005-Feb-02
Document File: 2 page(s) / 61K

Publishing Venue

IBM

Related People

Danen, RJ: AUTHOR [+2]

Abstract

Overlapped arithmetic operations are performed in the execution units of an engineering/scientific accelerator floating-point unit which do not have sufficient space or circuits for checking each operation separately within each execution unit chip. An arrangement of residue generators and checkers, which captures the residue of operands of overlapped operations and saves the residue until the result residue is developed for that operation (even though other operand results have occurred in the ensuing time), has been implemented to operate in the following manner. In the configuration shown in Fig.

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Offline Residue Checking for a Floating-Point Arithmetic Unit Executing Overlapped Operations

Overlapped arithmetic operations are performed in the execution units of an engineering/scientific accelerator floating-point unit which do not have sufficient space or circuits for checking each operation separately within each execution unit chip. An arrangement of residue generators and checkers, which captures the residue of operands of overlapped operations and saves the residue until the result residue is developed for that operation (even though other operand results have occurred in the ensuing time), has been implemented to operate in the following manner. In the configuration shown in Fig. 1, one register and residue generator can receive the operands at the same time that they are sent to the execution chips and can generate the required residue answer for the operation, even though the execution of the operations is overlapped. The two operands for the function are sent sequentially to the execution units (only one operand bus exists). Execution of the operations takes some time to perform; therefore, the residue generator can be used for developing a residue for all operations (Fig. 2). The operation type is known and is executed in the residue checker with modulo 3 arithmetic. The result is saved to

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compare to the modulo 3 residue of the result bus when execution of that operation is completed in the execution chip. The order of checking is...