INT 10h,  09h (9)        Write Character and Attribute at Cursor

    Displays a specified character with a specified attribute a specified
    number of times.

       On entry:      AX         09h
                      AL         ASCII value of character
                      BH         Display page (text mode only)
                      BL         Attribute/Color
                      CX         Number of times to write character

       Returns:       None

       Registers destroyed:      AX, SP, BP, SI, DI

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       Notes:         Display begins at the current cursor location on the
                      specified display page, but the cursor itself is not
                      moved.

                      In text mode, characters extending beyond the right
                      side of the screen wrap to the next line; in
                      graphics mode, they do not.

                      This service displays control characters as
                      printable characters, rather than as their cursor-
                      control equivalents. For example, if AL is 13, then
                      the musical note will be displayed, rather than a
                      Carriage Return.

                      In graphics modes, if the attribute (BL) is given
                      with bit 7 set, the color bits of the character
                      displayed are XORed with the color bits of the
                      current character. You can use this feature to write
                      characters and then erase them.

                      The difference between this service and Service 0Ah
                      is that this service allows the user to specify the
                      display attribute byte.