公开(公告)号：US3406296A

公开(公告)日：1968-10-15

申请号：US45128165

申请日：1965-04-27

Applicant: BELL TELEPHONE LABOR INC

Inventor： HUTTENHOFF JOHN H ,  SALTUS GEORGE E

IPC: H03K19/082

CPC classification number: H03K19/082

公开(公告)号：US3571803A

公开(公告)日：1971-03-23

申请号：US3571803D

申请日：1968-06-04

Applicant: BELL TELEPHONE LABOR INC

Inventor： HUTTENHOFF JOHN H ,  SHIVELY RICHARD R

IPC: G06F7/57 ,  G06F7/38 ,  G11C19/00

CPC classification number: G06F7/57 ,  G06F2207/3816

Abstract: An arithmetic unit of a data processing system having the capability of designating any digit position of the data words being processed as the most significant digit position to thereby increase the efficiency of processing. More than one most significant digit position in a data word may be so designated. Designating a most significant digit position is realized by circuitry in the arithmetic unit which (1) inhibits data from being shifted from the most significant digit position to adjacent positions in one direction, (2) inhibits arithmetic carrys from propagating from the most significant digit position to said adjacent positions, and (3) causes the sign digit of a data word to be copied into the most significant digit position as well as being shifted to adjacent positions in the other direction on certain ''''arithmetic'''' shifts of the data word.