Monthly Archives: February 2015


Explain any five DOS function calls supported by INT 21H in the 8086 assembly language with an example of each call. 10m jun2006

(d) Explain, with an example of each call, any five DOS function calls supported by INT 21H in the 8086 assembly language.             10

 

DOS Function Calls (Using INT 21H)

INT 21H supports about 100 different functions. A function is identified by putting the function number in the AH register. For example, if we want to call function number 01, then we place this value in AH register first by using MOV instruction and then call INT 21H:

Some important DOS function calls are:

Interrupt_INT21H

 

 

(a) Construct the Karnaugh map for the following function, and find the function in sum of product form. Draw the resultant logic diagram. F (A, B, C, D): Z (0, 2, 4, 5, 6, 7, 8, 10, 13, 15)      5

 

Similar Solved program can be found on this link http://cssimplified.com/assignments/use-a-karnaughs-map-to-design-an-odd-parity-generator-circuit-for-4-input-bits-ignou-mca-assignment-2014-15

 

(b) Draw the logic diagram for a 4 x 4 random access memory. Assume that the cells of RAM are made of R – S flip-flop.                        5

 

D flip-flop using R – S flip-flop Solved Answer can be found on this link http://thalia.spec.gmu.edu/~pparis/classes/notes_101/node116.html

And

Refer :- MCS-012 Block 1 page 101 and 102

 

(c) Seek time on a hard disk is 50 ms. it rotates at a speed of 3000 rotations/sec. Each track on the disk has 100 sectors. Find the average access time for the disk.     4

 

Similar Solved program can be found on this link http://cssimplified.com/assignments/what-is-rotational-latency-in-the-context-of-disk-access-time-ignou-mca-assignment-2014-15

 

(e) Explain, with an example, the following logic-microoperations:                       6

(i) Selective complement

(ii) Mask operations

(iii) Insert

(iv) Clear

 

Solved program can be found on this link http://cssimplified.com/computer-organisation-and-assembly-language-programming/registera-holds-the-8-bits-11011001-determine-the-b-operand-and-the-logic-micro-operation-to-be-performed-in-order-to-change-the-value-in-a-to-5m-dec2005

 

(f) What is the need of master slave flip-flop? Explain its functioning with the help of a suitable diagram.  6

Refer :- MCS-012 Block 1 page 93 and 94

Write a program to evaluate the following expression using an accumulator machine: A = B + C * D * E + F 7m jun2006

Write a program to evaluate the following expression using an accumulator machine: A = B + C * D * E + F     7m jun2006

 

Accumulator Architecture:

An accumulator is a specially designated register that supplies one instruction operand and receives the result. The instructions in such machines are normally one-address instructions. The popular architectures were IBM 7090, DEC PDP-8 etc.

 Accumulator Architecture: Pros and Cons

  • Implicit use of accumulator saves instruction bits.
  • Result is ready for immediate reuse, but has to be saved in memory.
  • More memory accesses required than stack.

 

Consider a program to do the expression:

A = B + C * D * E + F

 

Programs

Comments

LOAD C Load C in AC
MULT D Multiply D in AC  (i.e C * D)
MULT E Multiply E in AC  (i.e C * D * E)
ADD B Add B in AC (i.e B + C * D * E)
ADD F Add F in AC (i.e B + C * D * E +F)
STORE A Store Result in A

 

Accum_001

A program in 8086 assembly language that checks an input string against a password string stored in memory. 7m Jun2006

Write a program in 8086 assembly language that checks an input string against a password string stored in the memory and outputs an appropriate message if the strings are not equal.       7m Jun2006

DATA SEGMENT
MSG1 DB 10,13,’ENTERED PASSWORD : $’
MSG2 DB 10,13,’YOU HAVE ENTERED WRONG PASSWORD !!! $’
MSG3 DB 10,13,’YOU HAVE ENTERED CORRECT PASSWORD ! $’
MSG4 DB 10,13,’PASSWORD LENGTH IS NOT EQUAL $’

STR1 DB “NITIN”

P1 LABEL BYTE
M1 DB 0FFH
L1 DB ?
P11 DB 0FFH DUP (‘$’)
DATA ENDS

DISPLAY MACRO MSG
MOV AH,9
LEA DX,MSG
INT 21H
ENDM

CODE SEGMENT
ASSUME CS:CODE,DS:DATA
START:
MOV AX,DATA
MOV DS,AX

DISPLAY MSG1

LEA DX,P1
MOV AH,0AH
INT 21H

CMP L1,5
JNE NOTEQUAL

LEA SI,STR1
LEA DI,P11

MOV CX,5
CHECK:
MOV AL,[SI]
CMP [DI],AL
JNE NOPASWD
INC SI
INC DI
LOOP CHECK

DISPLAY MSG3
JMP EXIT

NOTEQUAL:
DISPLAY MSG4

NOPASWD:
DISPLAY MSG2
JMP EXIT

EXIT: MOV AH,4CH
INT 21H
CODE ENDS
END START

Program code: -

DATA SEGMENT
MSG1 DB 10,13,'ENTERED PASSWORD : $'
MSG2 DB 10,13,'YOU HAVE ENTERED WRONG PASSWORD !!! $'
MSG3 DB 10,13,'YOU HAVE ENTERED CORRECT PASSWORD ! $'
MSG4 DB 10,13,'PASSWORD LENGTH IS NOT EQUAL $'
STR1 DB "NITIN"
P1 LABEL BYTE
M1 DB 0FFH
L1 DB ?
P11 DB 0FFH DUP ('$')
DATA ENDS
DISPLAY MACRO MSG
MOV AH,9
LEA DX,MSG
INT 21H
ENDM
CODE SEGMENT
ASSUME CS:CODE,DS:DATA
START:
MOV AX,DATA
MOV DS,AX
DISPLAY MSG1
LEA DX,P1
MOV AH,0AH
INT 21H
CMP L1,5
JNE NOTEQUAL
LEA SI,STR1
LEA DI,P11
MOV CX,5
CHECK:
MOV AL,[SI]
CMP [DI],AL
JNE NOPASWD
INC SI
INC DI
LOOP CHECK
DISPLAY MSG3
JMP EXIT
NOTEQUAL:
DISPLAY MSG4
NOPASWD:
DISPLAY MSG2
JMP EXIT
EXIT: MOV AH,4CH
INT 21H
CODE ENDS
 
END START

Screen shots: -

Asm_program_Check_Password

After Execution: -

Asm_program_Check_Password_Output