Systems, apparatuses and methods for determining a trailing least significant masking bit of a writemask register

摘要

A zero mask before trailing (i.e. least significant) zero (KZBTZ) instruction is decoded and executed to find a least significant zero bit position in an first input mask 301 and sets an output mask 302 to have the values of the first input mask, but with all bit positions closer to the most significant bit position than the least significant zero bit position in the first input mask set to zero. In some embodiments, a second input mask 303 is used to determine which bit positions of the first input mask are considered in the least significant zero bit position calculation depending upon there being a 1 in a corresponding bit position in the second input mask. The masks are writemask operands and may be stored in write mask registers or general purpose registers.