Shift micro-operation :
Shift micro-operations in computer architecture are those which are used in serial shifting of data present in a register.
Shift micro-operations move or shift data in a register bitwise that is, one bit at a time either left or right from its original position.
List of different types of shift micro-operation :
a. Arithmetic shift micro-operation :
i. Arithmetic shift operation shifts signed (positive or negative) binary numbers either left or right by multiplying or dividing by 2.
ii. For arithmetic shift left micro-operation, the value in the register is multiplied by 2 and whereas for arithmetic shift right microoperation, the value in the register is divided by 2.
iii. In RTL (Register Transfer Language), we can represent this arithmetic shift micro-operations as R ← ashl R (arithmetic shift left R (register)) R← ashr R (arithmetic shift right R (register))
iv. image (a)showing arithmetic shift left operation is as follows :
v. Fig. 3.12.2 showing arithmetic shift right operation is as follows :
b. Logical shift micro-operation :
i. A logical shift micro-operation transfers a 0 (zero) through the serial input, either from left or right depending on the type.
ii. For logical shift left micro-operation, 0 (zero) is transferred through the right of the data and for the logical shift right micro-operation, 0 (zero is transferred through the left of the data as shown in the Fig.( c)
iii. Register Transfer Language (RTL) for the logical shift microoperations can be written as : R← shl R (shift left register (R)). R← shr R (shift right register (R)).
iv. Fig.(c) showing logical shift left micro-operation on the data in a register.
v. Fig. (d)showing the logical shift right is as follows :
c. Circular shift micro-operation :
i. A circular shift micro-operation performs the shifting of bits from one end of the register to the other end of the register.
ii. In circular shift left operation, the leftmost bit in the register is transferred to the rightmost end and in the circular shift right operation, the rightmost bit in the register is transferred or shifted to the leftmost end of the register as shown in the Fig. (E) and Fig. (F) respectively.
iii. Register transfer language for the circular shift micro-operations can be written as : R ← cil R (circular shift left register (R)).R ← cir R (circular shift right register (R)).
iv. Fig. (E) showing circular shift left micro-operation.
v. Fig. (F) showing circular shift right micro-operation.
