Structure your work

Structure your work

On drive M in your assembly directory, create a directory called week4.

After assembling and linking WEEK4A and WEEK4B, examine each program in the debugger.

e.g.
TD WEEK4A (will open the debugger and go through the code in week4a.exe)
(While in the debugger, pressing the F7 key will step through each line in your

program).

WEEK4A.ASM

• 
  Move 20h into ax
  
• 
  Move 30h into bx
  
• 
  Swap the contents of ax and bx (using no more than 3 mov instructions)
  

WEEK4B.ASM

Write an 8086 assembly language program to do the following:

• 
  Move 20h into ax
  
• 
  Move 30h into bx
  
• 
  Swap the contents of ax and bx (using no more than 1 xchg instruction).
  

WEEK4C.ASM

Key in the program below.

Which is the destination operand - ax or bx?

title week4c.asm

.model small

.stack 100h

.data

mov ax,4

add bx,ax

int 21h ; correctly

end

WEEK4D.ASM

title week4D.asm

.model small

.stack 100h

.data

.code

mov bx,5

int 21h ; correctly

end

What value will you see in the debugger for ax after the first 3 instructions have exectued? – Check your answer by using the debugger.

Exercise

Write down the hex values for each uppercase character from A through to Z.

The first two characters and the last character have been completed for you in the table below.
After you have completed the table on paper, check your answer on the internet.

Did you get it right – if not where did you go wrong?

B 42

.

.

WEEK4E.ASM

Take the program below and work out on paper what is in each of the registers after each instruction is executed. – The first 2 instructions have been completed for you in Table A below.

The complete program is given below:

title week4E.asm

.model small

.stack 100h

.data

mov ah,02h ;

mov dl,43h ; 3 lines to print capital C

int 21h ;

int 21h ; call os

int 21h ; call os

int 21h ; correctly

end

Table A

WEEK4F.ASM

The program from week4E.asm printed the letters CAR. Note that only two mov instructions were used.

Loop Exercises 1

WEEK4G.ASM

Write a loop to print all 26 uppercase letters (A through Z).

Program Output:

ABCDEFGHIJKLMNOPQRSTUVWXYZ

WEEK4H.ASM

Write a loop to print all 26 lowercase letters in descending order:

Program Output:

zyxwvutsrqponmlkjihgfedcba

WEEK4I.ASM

Write a loop to print the digits 9 through to 0

Program Output:

9876543210

WEEK4J.ASM

Write a loop to print the following

Program Output:

ABCDEFGHIJKLMNOPQRSTUVWXYZ

zyxwvutsrqponmlkjihgfedcba

WEEK4K.ASM

Write a loop to print ‘A’ 26 times.

Type in this program and get it to run.

WEEK4L.ASM

Write a program that takes in a single character.

Assume the character entered is a digit, n, in the range 1-9.

Print the first n digits.

E.g. user keys in 0 – Program Prints Out 0

E.g. user keys in 1 – Program Prints Out 01

E.g. user keys in 2 – Program Prints Out 012

E.g. user keys in 3 – Program Prints Out 0123

E.g. user keys in 4 – Program Prints Out 01234

E.g. user keys in 5 – Program Prints Out 012345

.

.

E.g. user keys in 9 – Program Prints Out 0123456789
You are to use one loop in your program.

Directory: ~mcmanusa -> notes -> c2p
c2p -> An Assembly Language Instruction
notes -> Firewall: What is a firewall?
notes -> Lab 11 Batch files

Download 39.91 Kb.

Share with your friends: