Dallas Semiconductor Corporation
             Spring 1985 VAX/VMS DECUS Tape Contribution






     This contribution consists of a set of macros which  support  the
VAX/VMS  V4.x  SMG$ RTL screen management routines from VAX-11 MACRO32
assembly language.

     Under the VMS V3.x SCR$ screen driver routines, it  was  possible
to  pass  numeric  values to the screen function routines as immediate
values from assembly language programs.  This functionality  does  not
exist under the version 4.x routines, as all numeric arguments must be
passed by reference.  This, in combination with the  large  number  of
arguments  required  by  the version 4.x SMG$ routines make the use of
them in MACRO32 quite difficult.  The enclosed  macros  allow  a  very
simple  access  mechanism  to  these  routines,  with  support for the
passing of  immediate  values  as  well  as  normal  pass-by-reference
calling mechanisms.

     As an example of how the SMG$ routines would be invoked using the
interface macros, examine the following source lines:


;----------------------------------------------------------------------;
;                                                                      ;
;       Create the virtual display                                     ;
;                                                                      ;
;----------------------------------------------------------------------;
        SMG$CREATE_VIRTUAL_DISPLAY-
                NUM_ROWS=#5,-
                NUM_COLUMNS=#12,-
                NEW_DISPLAY_ID=DID,-
                DISPLAY_ATTRIBUTES=R5,-
                VIDEO_ATTRIBUTES=R3
;----------------------------------------------------------------------;
;                                                                      ;
;       Paste the virtual display                                      ;
;                                                                      ;
;----------------------------------------------------------------------;
        SMG$PASTE_VIRTUAL_DISPLAY-
                DISPLAY_ID=DID,-
                PASTEBOARD_ID=PID,-
                PASTEBOARD_ROW=#22,-
                PASTEBOARD_COLUMN=#7



     As  you  can  see,  the  function  calls  directly  map  the  RTL
entrypoints  for  each SMG$ screen routine, and the function parameter
names match exactly the argument names given in the VMS  documentation
for  each  routine  entrypoint.   The only exception in routine naming
                                                                Page 2


takes place where the documentation is inconsistant.  In these  cases,
a naming convention for parameters was adopted to solve the problem.

     In addition to the normal  function  arguments  for  each  screen
function, there are also standard SUCCESS and FAILURE parameters which
can be specified to jump  to  success/error  processing  routines  for
special  case  processing.   By  default, all errors are signalled via
LIB$SIGNAL.

     These  routines  allow   very   rapid   development   of   screen
applications  in  MACRO32,  as all the overhead of generating argument
lists is removed from the code and buried in these support macros.  In
the  cases  of  immediate  value  arguments  (#5,  R3,  R6,  etc.) the
by-reference  argument  is  automatically  generated,   allowing   the
programmer  to  concentrate  on  application  development  rather than
argument list generation.

     I hope these macros are of use to other heavy  users  of  MACRO32
out  there,  as it seems that DEC has left us out in the cold with the
"new and improved" SMG$ services.  If you  have  problems  with  these
routines, please feel free to contact me personally:


                        Kevin Klughart
                        Dallas Semiconductor
                        4350 Beltwood Parkway South
                        Dallas, Texas 75244
                        (214) 450-0400