ASSEMBLY/LowToHigh.asm at main · AMMAAR-IC/ASSEMBLY · GitHub

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.model small
.stack 100h

.data
    msg     db 'Enter a lowercase string: $'
    str     db 20 dup(?)
    result  db 20 dup('$')
    newline db 13, 10, '$'

.code
main:
    mov ax, @data
    mov ds, ax
    mov es, ax

    lea dx, msg
    mov ah, 09h
    int 21h

    lea dx, str
    mov ah, 0Ah
    mov dx, offset buffer_struct
    int 21h

    lea si, buffer+2
    lea di, result

convert_loop:
    mov al, [si]
    cmp al, 13
    je done

    cmp al, 'a'
    jb skip_convert
    cmp al, 'z'
    ja skip_convert
    sub al, 32
skip_convert:
    mov [di], al
    inc si
    inc di
    jmp convert_loop

done:
    lea dx, newline
    mov ah, 09h
    int 21h

    lea dx, result
    mov ah, 09h
    int 21h

    mov ah, 4Ch
    int 21h

buffer_struct:
    db 20
    db ?
buffer:
    db 20 dup(?)

end main