6. Program to Random Strings in Assembly Language using Visual Studio

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Chapter 5

Procedures

Assembly Language Programming Exercise

Problem # 6:

Create a procedure that generates a random string of length L, containing all capital letters. When calling the procedure, pass the value of L in EAX, and pass a pointer to an array of byte that will hold the random string. Write a test  program that calls your procedure 20 times and displays the strings in the console window.

Solution:

INCLUDE Irvine32.inc
strLen=10
.data
arr BYTE strLen DUP(?)

.code
    main PROC
        call Clrscr
        mov esi, offset arr
        mov ecx, 20
        L1:
            call GenerateRandomString
        Loop L1
        call WaitMsg
        exit
    main ENDP

    GenerateRandomString PROC USES ecx  
        mov ecx, lengthOf arr
        L2:
            mov eax, 26
            call RandomRange
            add eax, 65
            mov [esi], eax
            call WriteChar        ; write character
        loop L2      
        call Crlf
        ret
    GenerateRandomString ENDP

END main