INT21 - 6521: Convert String

Programmering - Assembler - INT - INT21 - 6521: Convert String

DOS 3.3 : Converts each character in a specified string to uppercase using the current uppercase-table.
National charcters (æ, ø and å) are also converted.

AX = 6521
CX = string length in bytes
DS:DX -> string

CF = 0 : no error
CF = 1 : error

Replaces the original lower-case characters in the string with upper-case characters

Convert and display a string

msg       db  "ål og æblegrød",13,10
len       EQU $ - msg     ;length of msg

          call display
        
          mov dx, offset msg
          mov cx, len
          mov ax, 6521h   ;Convert String
          int 21h
          
          call display

          mov ax,4C00h    ;Terminate
          int 21h
  
display:  mov dx, offset msg
          mov cx, len
          mov bx, 1       ;Handle: screen

          mov ah, 40h     ;Write File or Device  
          int 21h
          ret

ål og æblegrød
ÅL OG ÆBLEGRØD