Question

Write an assembly program that demonstrates multiplication operation in 80x86 assy languuage

Answer 1

An 80x86 assembly program that demonstrates multiplication operation:

• Assume that we want to to perform multiplication of  two 8-bit number 04 and 06, that are at memory location 700 and 701 respectively.

• The 16-bit Result of the multiplication will be stored at memory location 800 and 801.

Assembly Program:

MOV SI, 700

MOV DI, 800

MOV AL, [SI]

INC SI

MOV BL, [SI]

MUL BL

MOV [DI], AX

HLT

Description:

MOV SI, 700 // SI = 700. Set the source index register to 700.

MOV DI, 800 // DI = 800. Set the Destination index register to 800.

MOV AL, [SI] // AL ← [SI]. load the contents from memory address SI to AL register. AL = 04

INC SI // SI = SI + 1. Increment the SI register value. SI = 701

MOV BL, [SI] // BL ← [SI]. load the contents from memory address SI to BL register. BL = 06

MUL BL // AX = AL * BL. Multiply register BL with AL. AX = 04 * 06

MOV [DI], AX // AX → [DI]. Store the content from AX register to destination address DI.

HLT // END the program.

The result is placed at memory location 800 and 801. Which is 04 * 06 = 18 (hexadecimal).