Addressing Modes

Type of Addressing Mode:-

- Immediate mode 

-  Register mode 

-  Absolute mode

-  Indirect mode

-  Index mode

-  Base with index  

-  Relative mode

-  Auto-increment mode

-  Auto-decrement mode 

 

• Immediate Addressing Mode

   The operand is given explicitly in the instruction.

              Eg: Move 200 immediate ,R0

       It places the value 200 in the register R0.The immediate mode used to specify the value of source operand. It can be re-written as

  

• Register Addressing Mode

The operand is the content of processor register’ the name of the register is given in the the instruction

Ex:-  MOV R1, R2

 

• Absolute or Direct Addressing Mode

    The operand is in a memory location; the address of this    location is given explicitly in the instruction.

          Ex. MOV LOC, R1

                 Consider,  LOC = 102

• Indirect Addressing Mode 

     Indicate the memory location that holds the address of the    memory location that holds the data

      Ex. MOV (R1), R2

 MOV (LOC) , R3

 

• Indexed Addressing Mode

    EA = Index Register (R1)  + Relative Address

          Ex.   Add 100(R1), R2

 

• Base  Index Addressing Mode

EA = Base Register(R2) + Relative Address (R1)

       Ex. MOV (R1, R2) , R3

 

• Relative Addressing Mode

EA = PC + Relative Address

   Ex. Jump 100(PC)

 

•  Autoincrement Addressing Mode

  In auto increment addressing mode, first operation is performed then the content of memory location is incremented by 1.

Ex.  ADD  (R1)+ , R2

•  Autodecrement Addressing Mode

 

  In auto increment addressing mode, first content of memory location is decremented by 1 then operation is performed.

Ex.  ADD  -(R1), R2