CASE CONVERSION

This is Microprocessor code for Converting Lower Case  letter to upper Case and Vice versa string is read from keyboard using BIOS function...
Algorithm is:

1. Initialize Data segment
2. read string from keyboard
3. point SI to start of string
4. Check Whether ASCII  value is less than 5Bh if yes add 20h
5. if ASCII value is greater than 60h then subtract 20h
6. Store the result in same location
7. repeat above steps for entire string length
8. After Checking with all the character display the result...

The code is:

;conversion of lower case to upper case

;Author: Akshath Kumar

;----------------------------------

data segment

msg1 db 10,13,"Enter string:",10,13,"$"

str1 db 10h,?,10h dup(' ')

len db 01h dup(0)

msg2 db 10,13,"Result is:",10,13,"$" 

data ends

;----------------------------------------

code segment

assume cs:code,ds:data

start:

        mov ax,data

        mov ds,ax

        mov bx,0h

        lea dx,msg1

        mov ah,09h

        int 21h

        lea dx,str1

        mov ah,10

        int 21h

        mov bl,str1[1]

        mov str1[bx+2],"$"

        mov len,bl

        mov bl,60h

        mov bh,20h

        lea si,str1+2

        mov cx,0h

        mov cl,len

up:     

        cmp [si],bl

        jae upper

        jb lower

upper:

        sub [si],bh

        jmp skip

lower:  add [si],bh

        jmp skip

skip:   inc si

        loop up

        lea dx,msg2

        mov ah,09h

        int 21h

        lea dx,str1+2

        mov ah,09h

        int 21h

        int 3h

        code ends

        end start

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