Browse Prior Art Database

Extended Shift Mechanism

IP.com Disclosure Number: IPCOM000055263D
Original Publication Date: 1980-Jun-01
Included in the Prior Art Database: 2005-Feb-13

Publishing Venue

IBM

Related People

Authors:
Letteney, RC Levine, SR Maass, KK [+details]

Abstract

The execution unit of large processors often has a 68-bit left ring shift shifter. All right shift amounts have to be put into the shift amount register (ESHAR) in the equivalent left shift. The shift direction bits (right or left) are used to force 0's (left bit from the right end; right bit from the left end) and to force those bits shifted out to checking. Thus, if a right 5 digits (20 bits) shift was wanted, the right bit and a shift amount of 12 digits (48 bits) would be turned on in the ESHAR 1 (see the figure).