There are basically 5 ways of specifying source/destination operand
1. Particular On-chip Resources:
This includes the Accumulator (A), the Stack Pointer (SP), the Data
Pointer (DP), the Program Counter (PC), and the Carry (C). Other On-chip
Registers are Memory-mapped while these have special Op-codes.
2. Immediate operands:
The # sign is the designator. These are 8-bits except for DPTR contents
3. Register operands:
Designated as Rn, where n is 0..7. One of the four Register Banks is
used (selected by RS0 and RS1 in PSW).
4. Direct Operands:
From 00 to FF Hex, specifies one of the internal data addresses.
5. Indirect Address:
Designated as @Ri, where i is 0 or 1, uses the contents of R0 or R1 in
the selected Register Bank to specify the address. Other form is @A,
using Accumulator contents.
Addressing modes are an integral part of each computers instruction
set. They allow different ways of specifying source/destination operand
addresses depending on the programming situation. There are 8 modes of