Patent ID: 6029243
Filing Date: 2000-02-22
Classification: G06F

Abstract:
A floating-point processor for a multiple-precision computer system that performs a floating-point operation on an operand set of operands and that yields the result in a requested result precision, said requested result precision being selected from a precision set of at least two precisions including a highest precision, each precision of said precision set having a corresponding numerical format so that said highest precision has a highest-precision format, each operand of said operand set having a nominal precision, each operand of said operand set having an exponent and a mantissa, each operand of said operand set having an apparent precision that is a function of the number of trailing zeroes in its mantissa, said operand set having a maximum apparent precision equal to the maximum of the apparent precisions of said operands, said floating-point processor comprising:input means for receiving said operand set, and a set of instructions specifying said operation and said requested result precision;format conversion means for converting operands of said operand set not in said highest-precision format into said highest-precision format;register means for storing said operands of said operand set in said highest precision format;precision selection means for selecting an execution precision as a function of said requested result precision and said maximum apparent precision;an execution unit for performing said operation with said execution precision on said operand set to yield an execution result when said execution precision is not said highest precision; andtrap means for executing a trap when said execution precision is said highest precision;whereby, in response to said trap, said computer system can perform said operation in software at said highest precision.