Apparatus and method for processing fractional reciprocal operations

A method comprising:

• decoding an instruction;
• executing the decoded instruction to use a first portion of a packed input data element of a source register 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, wherein the packed input data element comprises a doubleword and wherein the first portion of the packed input data element comprises two bits to index a coefficient table containing four entries, and
• generating and storing in a destination register a reciprocal of the packed input data element using a combination of the coefficients and a second portion of the packed input data element, wherein combining the coefficients with the second portion of the packed input data element comprises multiplications of the coefficients and the second portion of the packed input data element.

A non-transitory machine-readable medium having program code stored thereon which, when executed by a machine, causes the machine to perform the operations of:

• decoding an instruction;
• executing the decoded instruction to use a first portion of a packed input data element of a source register 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, wherein the packed input data element comprises a word and wherein the first portion of the packed input data element comprises three bits to index a coefficient table containing eight entries, and
• generating and storing in a destination register a reciprocal of the packed input data element using a combination of the coefficients and a second portion of the packed input data element, wherein combining the coefficients with the second portion of the packed input data element comprises multiplications of the coefficients and the second portion of the packed input data element.