**Addressing Modes of 80386 Microprocessor:**

The 80386 can operate in all the addressing modes which were available with the 80286 processor. The 80386 processor can also operate in all addressing modes of 80286 with 32-bit immediate or 32-bit register operands or displacements. Besides all addressing modes of 80286, the 80386 has a family of scaled modes. In the scaled modes, the index register values will be multiplied by a valid scale factor to get the final displacement. The valid scale factors are 1, 2, 4 and 8. In this section, all scaled modes are briefly explained.

**Scaled Indexed Mode **The content of an index register is multiplied by a scale factor 1, 2, 4 or 8 and subsequently the computed value will be added to get the final operand offset. For example,

**Based Scaled Indexed Mode **The based scaled indexed mode instruction is the content of an index register is multiplied by a scale factor and the computed value is added with the base register to find the offset.

**Based Scaled indexed Mode with Displacement **The based scaled indexed mode with displacement instruction is the content of an index register multiplied by a scaling factor and the computed value is added with the content of base register and a displacement to obtain the address of an operand. The offset can be expressed as

and the 32-bit memory address is computed by

The above expression can be expressed for different registers as given below:

The example of based scaled indexed mode with displacement instructions are