Some Examples - IQ

1) To write 8086 Assembly Language Program to Multiply two unsigned number.
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MODEL SMALL
.STACK 100
.DATA ; Data Segment to initialize the variables
A DW 0FF87H ; First signed number A = (-79H) = FF87H (2'Compliment form)
B DW 0FF84H ; Second signed number B = (-7CH) = FF84H (2'Compliment form)
C DW ? ; Variable C to store result

.CODE 
START: 
MOV AX,@DATA
MOV DS,AX ; Initialize data segment
MOV SI,0000H ; Initialize SI to 0000H
MOV AX,A ;Take first number A in AX register
MOV CX,B ;Take second number B in CX register
MUL CX ; Performs unsigned Multiplication DX:AX = AX × CX
MOV C[SI],DX ; Store higher 16-bit result
MOV C[SI+2],AX ; Store lower 16-bit result
INT 03H

END START

Input:
FF87 × FF84 = FF0B 3A9C H
A = 0FF87 H (2'compliment of -79H)
B = 0FF84 H (2'compliment of -7CH)
Output:
C = FF0B 3A9C H 
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2) To write 8086 Assembly Language Program to multiply two signed number.
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MODEL SMALL
.STACK 100
.DATA ; Data Segment to initialize the variables
A DW 0FF87H ; First signed number A = (-79H) = FF87H (2'Compliment form)
B DW 0FF84H ; Second signed number B = (-7CH) = FF84H (2'Compliment form)
C DW ? ; Variable C to store result

.CODE 
START: 
MOV AX,@DATA
MOV DS,AX ;Initialize data segment
MOV SI,0000H ;Initialize SI to 0000H
MOV AX,A ;Take first number A in AX register
MOV CX,B ;Take second number B in CX register
IMUL CX ; Performs signed Multiplication DX:AX = AX × CX
MOV C[SI],DX ;Store higher 16-bit result
MOV C[SI+2],AX ;Store lower 16-bit result
INT 03H

END START

Input:
-79 × -7C = 3A9C H
A = 0FF87 H (2'compliment of -79H)
B = 0FF84 H (2'compliment of -7CH)
Output:
C = 0000 3A9C H
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3) To write 8086 Assembly Language Program to multiply two 32-bit unsigned numbers.
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MODEL SMALL
.STACK 100
.DATA ; Data segment starts
A DW 5678H, 1234H, 5 DUP(0) ;A is 32bit number A=1234 5678
b DW 1111H, 1111H, 5 DUP(0) ;B is 32bit number B=1111 1111
C DW 4 DUP(?) ; Reserve 4 words of uninitialized data space to an offset C
.CODE
START:
MOV AX,@DATA ;Initialize DS
MOV DS,AX
MOV SI,OFFSET A ;Point to first number in A

MOV AX,WORD PTR A[SI] ;Take lower 16bits(5678) of A into AX
MUL WORD PTR B[BX+0] ;Multiply AX with lower 16bits of B(1111) and store in AX
MOV C[DI],AX ;Move the contents of AX to C[DI]
MOV CX,DX ;Move the value of DX to CX

MOV AX,WORD PTR A[SI+2] ;Take higher 16bits(1234) of A into AX
MUL WORD PTR B[BX+0] ;Multiply AX with lower 16bits of B(1111)and store in AX
ADD CX,AX ;CX=CX+AX
MOV C[DI+2],CX ;Move the contents of CX to C[DI+2]
MOV CX,DX ;Move contents of DX to CX

MOV AX,WORD PTR A[SI] ;Take lower 16bits(5678) of A in AX
MUL WORD PTR B[BX+2] ;Multiply contents of AX with higher 16bits of B(1111)
ADD WORD PTR C[DI+2],AX ;C[DI+2]=C[DI+2]+AX
ADC CX,DX ;CX=CX+DX+CF
MOV C[DI+4],AX ;Move contents of AX to C[DI+4]

MOV AX,WORD PTR A[SI+2] ;Take higher 16bits of A(1234) into AX
MUL WORD PTR B[BX+2] ;Multiply AX with higher 16bits of B(1111) and store in AX
ADD CX,AX ;CX=CX+AX
MOV WORD PTR C[DI+4],CX ;Move contents of CX to C[DI+4]
ADC DX,0000 ;DX=DX+0000+CF
MOV C[DI+6],DX ;Move the contents of DX to C[DI+6]

INT 03H ; Halt

END START 

INPUT 
A = 1234 5678 H 
B = 1111 1111 H
OUTPUT
C=0136 BO6E 652F B5F8 H
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4) To write 8086 Assembly Language Program to Division two unsigned number.
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MODEL SMALL
.STACK 100
.DATA ; Data Segment to initialize the variables
Dividend DW 1234H, 5678H ; Dividend = 1234 5678 H
Divisor DW 270FH ; Divisor = 207FH
Quotient DW ? ; Variable Quotient to store Quotient
Reminder DW ? ; Variable Reminder to store Reminder

.CODE 
START: 
MOV AX,@DATA
MOV DS,AX ;Initialize data segment
MOV SI,0000H ;Initialize SI to 0000H
MOV DX,Dividend[SI] ;Take higher 16-bit number which is to be divided in DX register
MOV AX,Dividend[SI+2] ;Take lower 16-bit number which is to be divided in AX register
MOV CX,Divisor ;Take divisor in CX register
DIV CX ; Performs unsigned Division DX:AX ÷CX
; AX = Quotient DX = Reminder
MOV Reminder,DX ;Store Reminder
MOV Quotient,AX ;Store Quotient
INT 03H
END START

Input:
12345678H ÷ 207FH = 7751H
Dividend = 1234 5678 H
Divisor = 207F H
Output:
Quotient = 7751 H
Reminder = 01B9 H
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5) To write 8086 Assembly Language Program to Division two signed number.
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MODEL SMALL
.STACK 100
.DATA ; Data Segment to initialize the variables
Dividend DW 0FFFFH, 0FF88H ; Dividend = (-78H) = FFFF FF88H (2'Compliment form)
Divisor DW 0006H ; Divisor = 0006H
Quotient DW ? ; Variable Quotient to store Quotient
Reminder DW ? ; Variable Reminder to store Reminder

.CODE 
START: 
MOV AX,@DATA
MOV DS,AX ;Initialize data segment
MOV SI,0000H ;Initialize SI to 0000H
MOV DX,Dividend[SI] ;Take higher 16-bit number which is to be divided in DX register
MOV AX,Dividend[SI+2] ;Take lower 16-bit number which is to be divided in AX register
MOV CX,Divisor ;Take divisor in CX register
IDIV CX ; Performs signed Division DX:AX ÷ CX
; AX = Quotient DX = Reminder
MOV Reminder,DX ;Store Reminder
MOV Quotient,AX ;Store Quotient
INT 03H

END START

Input:
-78H ÷ 06H = -14H
Dividend = FFFF FF87 H (32-bit 2'compliment of -78H)
Divisor = 0006 H
Output:
Quotient = FFEC H (2'compliment of -14H)
Reminder = 0000 H