Create a file with handle (INT 21h, 3Ch - CREAT)

        Entry:
          AH = 3Ch
          CX = attributes for file
          DS:DX = address of ASCIZ filename
        Return:
          CF = 1 if error
                  AX = Error Code
          CF = 0 successful
                  AX = file handle
        Note:
           If a file with the given name exists, it is truncated to
           zero length