SAMPLE DEBUG PROGRAM

DEBUG

Enter:  E  address  [list]

    Used to enter data or instructions (as machine code) directly into Memory locations.

    Example. First we'll change a single byte at location 0200 from whatever it was before to D2 :

   -e 0200  d2

This next example shows that either single(') or double(") quote marks are acceptable for entering ASCII data. By allowing both forms, entry strings can be created to include either type of quote mark as data:

   -e 200 'An "ASCII-Z string" is always followed by '

   -e 22a "a zero-byte ('00h')." 0

Now we'll examine a string of 11 hex bytes you can enter into Memory at locations CS:0100 and following:

   -e 100 B4 09 BA 0B 01 CD 21 B4 00 CD 21

To view the content of  memmory location  frome 2010 is

-e 2010 (enter key ) space  space  ......

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Write an ALP to add  two16 bit numbers.

Input:

 n0 -->stored in 0200 ,n1---> 0201 and n2--->  0202,n3---. 0203

Output:

sum; n1n0+ n3n2---->AX

carry--->BX

a100

mov ax,[200]

mov bx,00

add ax,[202]

jnc 10d

inc bx

hlt

q

-------------------------------x

Write an ALP to find factorial of a number

Input : Number --->AX

Output:

Factorial ---->AX

a100

MOV AX, 05

MOV CX, AX

DEC CX

JZ 10c

MUL CX

Jmp 105

HLT

q

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an example of how to read the time  from a computer's "real time clock" (RTC)

rtc available in port no.71. If port 70 is 04---> port 71 loaded Hrs, :70--. 02: 71---.>minuts: 70---> and 00--->seconds

output :

hr:min--->BX

sec     ---->CH

a100

Mov al,04

Out 70,al

In al,71

Mov bh,al

Mov al,02

Out 70,al

In al,71

Mov bl,al

Mov al,00

Out 70,al

In al,71

Mov ch,al

Hlt

q

-------------------------x

Display  strings in monitor using dos function 21h

a100

jmp 126      ; Jump over data that follows:

db  0d,0a,"This is my first DEBUG program!"

db  0d,0a,"$"; End of string marker above: "$"=24h

mov ah,9     ; Function 09 of Int 21h:

mov dx,102   ; DS:DX -> $-terminated string.

int 21       ; Write String to STD Output.

mov ah,0     ; Function 00 of Int 21h:

int 21       ; Terminate Program.

q

--------------------x

32-bit subtraction of 2 32 bit numbers X and Y that are stored in the

memory as

– X = (203)(:202)(:201)(:200)

– Y = (:303)(:302)(:301)(:300)

• The result X - Y to be stored where X is saved in the memory

a100e

MOV SI, 200

MOV DI, 300

MOV AX, [SI]

SUB AX, [DI]

MOV [SI], AX ;save the LS word of result

MOV AX, [SI] +2

SBB AX, [DI]+2

MOV [SI] +2, AX

hlt

q

---------------x

Write a program that calculates the average of five temperatures and writes

the result in AX

Data  at 1030 -à 0d, f6,13,0e, ee : +13,-10,+19,+14,-18

a100

MOV CX,5           ;LOAD COUNTER

SUB BX,BX           ;CLEAR BX, USED AS ACCUMULATOR

MOV SI,0130      ;load pointer

 MOV AL,[SI]      ;MOVE BYTE INTO AL

CBW                      ;SIGN EXTEND INTO AX

ADD BX,AX          ;ADD TO BX

INC SI                    ; INCREMENT POINTER

DEC CX                 ;decrement counter

JNZ 0108              ;LOOP IF NOT FINISHED

MOV AL,5            ;MOVE COUNT TO AL

CBW                      ;SIGN EXTEND INTO AX

MOV CX,AX        ;SAVE DENOMINATOR IN CX

MOV AX,BX        ;MOVE SUM TO AX

CWD                      ;SIGN EXTEND THE SUM

IDIV CX                                 ;FIND THE AVERAGE

Q

For entering data ,

e 1030 0d f6 13 0e ee

exercises

1) Write an ALP to add / two 64  bit numbers.

2) Write an ALP to check if the given number is even or odd.

3)Write an ALP to find the smallest of ‘N’ 8 bit numbers and display the result.

4) Write an ALP to sort the given set of 16 bit unsigned integers in ascending order

using bubble sort algorithm.