Types of Micro-operations:
Register Transfer Micro-operations: Transfer binary information from one register to another.
Arithmetic Micro-operations: Perform arithmetic operation on numeric data stored in registers.
Logical Micro-operations: Perform bit manipulation operations on data stored in registers.
Shift Micro-operations: Perform shift operations on data stored in registers.
The basic arithmetic micro-operations are
The arithmetic Micro-operation defined by the statement below specifies the add micro-operation.
R3 ← R1 + R2
It states that the contents of R1 are added to contents of R2 and sum is transferred to R3.
To implement this statement hardware requires 3 registers and digital component that performs addition
Subtraction is most often implemented through complementation and addition.
The subtract operation is specified by the following statement
R3 ← R1 + R2 + 1
instead of minus operator, we can write as
R2 is the symbol for the 1’s complement of R2
Adding 1 to 1’s complement produces 2’s complement
Adding the contents of R1 to the 2's complement of R2 is equivalent to R1-R2 Logic Micro-operations:
Logic microoperations specify binary operations for strings of bits stored in registers.
These operations consider each bit of the register separately and treat them as binary variables.
For example, the exclusive-OR microoperation with the contents of two registers RI and R2 is symbolized by the statement
It specifies a logic microoperation to be executed on the individual bits of the registers provided that the control variable P = 1
Shift microoperations are used for serial transfer of data.
The contents of a register can be shifted to the left or the right.
During a shift-left operation the serial input transfers a bit into the rightmost position.
During a shift-right operation the serial input transfers a bit into the leftmost position.
There are three types of shifts: logical, circular, and arithmetic.
The symbolic notation for the shift microoperations