Original Publication Date: 1980-Jun-01
Included in the Prior Art Database: 2005-Feb-13
Certain computer architectures include instructions which require the generation and use of masks as part of their execution. The masks are of predefined length and fall into two classes. In class 1, the mask consists of either ones surrounded by zeros or, conversely, zeros surrounded by ones. It is specified by providing a starting bit number (BI - initial mask bit), an ending bit number (BF - final mask bit) and a bit to define whether the mask's control portion is to be ones or zeros. Class 2 masks are a special form of class 1 masks in which the mask string always starts with the first bit. Only one number is necessary to specify the mask length and one bit to specify whether the mask is to be ones followed by zeros or zeros followed by ones.