Extended Shift Mechanism
Original Publication Date: 1980-Jun-01
Included in the Prior Art Database: 2005-Feb-13
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).