Displacement addressing

Displacement addressing a presentation by Mourin

1. Displacement Addressing
By Mourin Mondol [152-35-1298]

2. What is
displacement
addressing?
A very powerful mode of
addressing combines the
capabilities of direct
addressing and register
indirect addressing.

3. EA = A + (R)
where,
A = Memory address
R = Register address
EA = Effective address

4. Why & Why not?
Flexibility Complexity
●When we need flexibility we should use it.
●Otherwise for its complexity we should avoid this.

5. Example:
5
10001001100210031004
Register Address: 20
Displacement =2
…..
Register
Displacement=2
Effective Address=1001+2 =1003
100010011002100310041005Memory
10 20 30 40 50

6. 3 COMMON
USES
●RELATIVE ADDRESSING
●BASE-REGISTER
●INDEXING
[Relative]: referenced register is
the program counter (PC)
[Base-register]: referenced register
contains a main memory
address and the address field
contains a displacement from
that address.
[Indexing]: address field references
a main memory address, and
referenced register contains a
positive displacement from that
address.

7. Any Questions?