Problem – Write an assembly language program in 8086 microprocessor to divide a 16 bit number by an 8 bit number.
- Assign value 500 in SI and 600 in DI
- Move the contents of [SI] in BL and increment SI by 1
- Move the contents of [SI] and [SI + 1] in AX
- Use DIV instruction to divide AX by BL
- Move the contents of AX in [DI].
- Halt the program.
Assumption – Initial value of each segment register is 00000.
Calculation of physical memory address –
Memory Address = Segment Register * 10(H) + offset,
where Segment Register and Offset is decided on the basis of following table.
|Instruction fetching||Code Segment||Instruction Pointer|
|Data operation||Data Segment||Base Register [BX], Displacement [DISP]|
|Stack operation||Stack Segment||Stack Pointer (SP), Base Pointer (BP)|
|String as a source||Data Segment||Source Indexed (SI)|
|String as a destination||Extra Segment||Destination Indexed (DI)|
|0400||MOV SI, 500||SI <- 500|
|0403||MOV DI, 600||DI <- 600|
|0406||MOV BL, [SI]||BL <- [SI]|
|0408||INC SI||SI <- SI + 1|
|0409||MOV AX, [SI]||AX <- [SI]|
|040B||DIV BL||AX <- AX / BL|
|040D||MOV [DI], AX||[DI] <- AX|
|040F||HLT||End of program|
Explanation – Registers used AX, BL, SI, DI
- MOV SI, 500 assigns 500 to SI
- MOV DI, 600 assigns 600 to DI
- MOV BL, [SI] moves the content of [SI] to BL register i.e. value of divisor will be stored in BL
- INC SI increment the content of SI by 1
- MOV AX, [SI] moves the content of [SI] and [SI + 1] to AX register i.e. value of dividend will be stored in AX
- DIV BL divide the content of AX by BL, after execution of this instruction the quotient get stored in AL and remainder in AH
- MOV [DI], AX moves the content of AX to [DI]
- HLT stops executing the program and halts any further execution
Attention reader! Don’t stop learning now. Get hold of all the important CS Theory concepts for SDE interviews with the CS Theory Course at a student-friendly price and become industry ready.