Patent Number: 7,712,076

Title: Register indirect access of program floating point registers by millicode

Abstract: Complex floating point instructions are executed under millicode control when it is not cost effective to implement its function in hardware. One of the disadvantages to executing complex instructions using millicode routines is that determining and accessing the instructions operands are costly for millicode performance. To determine what the source and target location are, the instruction text is parsed. Furthermore the millicode instruction stream must be modified to access the operand data from and write the result to the program registers specified by the complex floating point instruction. The invention overcomes these disadvantages by providing millicode with register indirect access to the program floating point registers.

Inventors: Carlough; Steven R. (Poughkeepsie, NY), Farrell; Mark S. (Pleasant Valley, NY), Schwarz; Eric M. (Gardiner, NY), Slegel; Timothy J. (Staatsburg, NY), Webb; Charles F. (Wappingers Falls, NY)

Assignee: International Business Machines Corporation

International Classification: G06F 9/44 (20060101)

Expiration Date: 5/04/12018