A hardware logic representation of a circuit to implement an operation to perform multiplication by an invariant rational is generated by truncating an infinite single summation array (which is represented in a finite way). The truncation is performed by identifying a repeating section and then discarding all but a finite number of the repeating sections whilst still satisfying a defined error bound. To further reduce the size of the summation array, the binary representation of the invariant rational is converted into canonical signed digit notation prior to creating the finite representation of the infinite array.

An execution unit for a processor, the execution unit comprising: a look up table having a plurality of entries, each of the plurality of entries comprising an initial estimate for a result of an operation; a preparatory circuit configured to search the look up table using an index value dependent upon the operand to locate an entry comprising a first initial estimate for a result of the operation; a plurality of processing circuits comprising at least one multiplier circuit; and control circuitry configured to provide the first initial estimate to the at least one multiplier circuit of the plurality of processing circuits so as perform processing, by the plurality of processing units, of the first initial estimate to generate the function result, said processing comprising applying one or more Newton Raphson iterations to the first initial estimate.

A hardware logic representation of a circuit to implement an operation to perform multiplication by an invariant rational is generated by truncating an infinite single summation array (which is represented in a finite way). The truncation is performed by identifying a repeating section and then discarding all but a finite number of the repeating sections whilst still satisfying a defined error bound. To further reduce the size of the summation array, the binary representation of the invariant rational is converted into canonical signed digit notation prior to creating the finite representation of the infinite array.

A hardware logic representation of a circuit to implement an operation to perform multiplication by an invariant rational is generated by truncating an infinite single summation array (which is represented in a finite way). The truncation is performed by identifying a repeating section and then discarding all but a finite number of the repeating sections whilst still satisfying a defined error bound. To further reduce the size of the summation array, the binary representation of the invariant rational is converted into canonical signed digit notation prior to creating the finite representation of the infinite array.

Techniques are disclosed relating to circuitry configured to perform reciprocal-based floating-point division. In some embodiments, floating-point circuitry includes reciprocal circuitry configured to generate a reciprocal of a divisor, multiplication circuitry configured to multiply the reciprocal results with a dividend, and circuitry configured to clear a least significant bit of an integer representation of the multiplication output to generate a modified multiplication output. The floating-point circuitry may be configured to convert the modified multiplication output to a representation using the first precision to generate a division output. In some embodiments, the refinement using the integer representation may provide correctly-rounded subnormal division results. The disclosed techniques may improve accuracy, reduce processing time, and/or reduce instructions needed for floating-point division, with little to no increase in chip area.

A secure computation technique of calculating a polynomial in a shorter calculation time is provided. A secure computation system includes: a comparing means 120 that generates concealed text [[u]] of u, which is the result of magnitude comparison between a value x and a random number r, from concealed text [[x]] by using concealed text [[r]]; a mask means 130 that generates concealed text [[c]] of a mask c from the concealed text [[x]], [[r]], and [[u]]; a reconstructing means 140 that reconstructs the mask c from the concealed text [[c]]; a coefficient calculating means 150 that calculates, for i=0, . . . , n, a coefficient b.sub.i from an order n, coefficients a.sub.0, a.sub.1, . . . , a.sub.n, and the mask c; a selecting means 160 that generates, for i=1, . . . , n, concealed text [[s.sub.i]] of a selected value s.sub.i, which is determined in accordance with the result u of magnitude comparison, from the concealed text [[u]]; and a linear combination means 170 that calculates a linear combination b.sub.0+b.sub.1[[s.sub.1]]+ . . . +b.sub.n[[s.sub.n]] of the coefficient b.sub.i and the concealed text [[s.sub.i]] as concealed text [[a.sub.0+a.sub.1x.sup.1+ . . . +a.sub.nx.sup.n]].

A reciprocal approximation circuit has a first iteration circuit for generating an approximate reciprocal value of an operand. The operation of the first iteration circuit is controlled by two bits of the operand, which indicate a range in which the operand lies. The first iteration circuit uses hardware friendly initial values based on the two bits for generating the approximate reciprocal value. The reciprocal approximation circuit does not require any additional circuit for selecting an initial value for the first iteration circuit.

An output value generator circuit possesses an output unit (reciprocal output unit) configured to generate a mantissa and a characteristic of an output value in floating-point representation, and individually output the mantissa and the characteristic. The output value is obtained by conversion of an input value.

A hardware logic representation of a circuit to implement an operation to perform multiplication by an invariant rational is generated by truncating an infinite single summation array (which is represented in a finite way). The truncation is performed by identifying a repeating section and then discarding all but a finite number of the repeating sections whilst still satisfying a defined error bound. To further reduce the size of the summation array, the binary representation of the invariant rational is converted into canonical signed digit notation prior to creating the finite representation of the infinite array.

An apparatus and method for performing a reciprocal. For example one embodiment of a processor comprises: a decoder to decode a reciprocal instruction to generate a decoded reciprocal instruction; a source register to store at least one packed input data element; a destination register to store a result data element; and reciprocal execution circuitry to execute the decoded reciprocal instruction, the reciprocal execution circuitry to use a first portion of the packed input data element as an index to a data structure containing a plurality of sets of coefficients to identify a first set of coefficients from the plurality of sets, the reciprocal execution circuitry to generate a reciprocal of the packed input data element using a combination of the coefficients and a second portion of the packed input data element.