Dual look ahead mask generator.

摘要

A mask generator for generating a mask having logical signals of a given level between positions indicated by beginning and ending addresses. Two decoders select respective binary signal lines indicating the starting and ending positions. The mask generator is composed of two mask generators operating on the higher and lower order binary signal lines respectively and which ripple from the ends of the mask towards the middle. Preferably, each of the dual mask generators has look-ahead carry capability.