Int 03  U - Watcom Wvideo, Watcom Wd - Output Debugging Message            [G]

   STACK:  DWORD   selector
       DWORD   offset of ASCIZ message to display

Notes: the INT 03h instruction which invokes the debugger must be followed by
     a JMP SHORT and the signature string "WVIDEO"
   to check whether this interface is available, define a public byte
     variable named ___WD_Present, which the debugger will set to 01h
     before running the program

See Also: AX=0910h