STEP causes your program to execute one instruction or one  line,
     or one of some other kind of "unit" depending on qualifier.  When
     you step, the address that you step to is reported.  If  you  are
     stepping   by   instruction,   then  you  will  see  the  machine
     instruction at the address that you have stepped to.  If you have
     done  SET  STEP  SOURCE  and source display is available for your
     language then you will also see the source line corresponding  to
     the location you have stepped to.

 Format:

     STEP [/qualifier] [n]

Additional information available:

ParametersQualifiersExample

/BRANCH/CALL/EXCEPTION/INSTRUCTION/INSTRUCTION
/INTO/JSB/LINE/NOJSB/NOSILENT/NOSHARE/NOSOURCE
/NOSYSTEM/OVER/RETURN/SHARE/SILENT/SOURCE
/SYSTEM

 n

     Specifies the number of steps to perform before stopping.  If you
     do not specify a parameter, then "n" defaults to 1.

     The qualifiers can be grouped as follows:

     These tell the debugger how far to step:
         /BRANCH       /CALL    /EXCEPTION    /LINE      /RETURN
         /INSTRUCTION  /INSTRUCTION=(opcode-list)
     These control how much information to display at each step:
         /[NO]SILENT   /[NO]SOURCE
     These determine what the debugger does at a routine call:
         /INTO         /OVER    /[NO]SYSTEM  /[NO]SHARE  /[NO]JSB

     Note that each of the above can  also  be  used  in  a  SET  STEP
     command.  See the individual help topic on each of these for more
     information.

     Causes the step command to step to the next  branch  instruction.
     This has the same effect as "SET BREAK/BRANCH;GO".

     Causes the step command to  step  to  the  next  call  or  return
     instruction.  This has the same effect as "SET BREAK/CALL;GO".

     Causes the step command to step  to  the  next  exception  (i.e.,
     error    signal).    This   has   the   same   effect   as   "SET
     BREAK/EXCEPTION;GO".

     Causes the step command to step a single machine instruction.

     This allows you to step to the next instruction which is  in  the
     given  opcode  list.  For example, STEP/INST=(ADDL3) will step to
     the next "ADDL3" instruction in your program.

     If you are at a CALL statement, then STEP/INTO allows you to step
     into  the  called subroutine.  The /INTO qualifier may be further
     refined by /NOSHARE, /NOSYSTEM, or /NOJSB.  See those help topics
     for details.

     /JSB, which is the default, simply says that on a STEP/INTO,  the
     debugger  should  not  distinguish  between JSB routines and CALL
     routines.  /NOJSB is mainly used  for  language  DIBOL  (see  the
     /NOJSB help topic for further explanation).

     Causes the step command to step to the next line of your program.

     NOJSB is a refinement of INTO.  "SET STEP  INTO,NOJSB"  specifies
     that  you want to step into called subroutines if they are called
     with the CALL instruction but not if they are called with the JSB
     instruction.   /NOJSB was mainly put in for language DIBOL, where
     the DIBOL run-time library is always called with JSB instructions
     but   your   DIBOL   subroutines  are  always  called  with  CALL
     instructions.  Therefore, for DIBOL, /NOJSB is  the  default,  so
     that  you  do  not  step  into  the  DIBOL  run-time library on a
     STEP/INTO.  For all other languages, /JSB is the default  meaning
     that  no distinction is made between JSB and CALL instructions on
     a STEP command.

     Opposite of /SILENT.  /NOSILENT, which  is  the  default,  simply
     specifies  that  you  do want to see the "stepped to" message and
     other STEP output.

     NOSHARE  is  a  refinement  of  INTO.   "SET  STEP  INTO,NOSHARE"
     specifies  that  you want to step into called subroutines if they
     are part of your main image, but  not  if  they  are  part  of  a
     shareable  image  (e.g.,  an RTL routine).  For example, to trace
     all lines of execution in your program,  but  not  including  RTL
     routines, you could specify "SET TRACE/LINE/NOSHARE".

     Specifies that you do not want to see source display during  this
     step command.  You may want to say "SET STEP NOSOURCE" if you are
     in screen mode because  with  the  screen  mode  source  display,
     source display on each STEP command would be redundant.

     NOSYSTEM is a  refinement  of  INTO.   "SET  STEP  INTO,NOSYSTEM"
     specifies  that  you want to step into called subroutines if they
     are part of your main image, but not step into a system  service.
     For example, to trace all lines of execution in your program, but
     not including system services or RTL routines, you could  specify
     "SET    TRACE/LINE/NOSYSTEM/NOSHARE".    (DEBUG   actually   just
     identifies a system service by its address being in P1 space.  So
     "SET  STEP  NOSYSTEM" prevents you from stepping into any routine
     whose address is in P1 space.)

     If you are at a CALL statement, then STEP/OVER allows you to step
     over the called subroutine.  /OVER is the opposite of /INTO.

     Causes the step command to step to the return instruction of  the
     routine that you are now in.

     Opposite of /NOSHARE.  /SHARE, which is the default, simply  says
     that  DEBUG should feel free to step into called subroutines that
     are in shareable images (e.g., RTL routines).

     Causes the  step  command  to  be  "silent",  i.e.,  neither  the
     "stepped to" message nor the source display are given.

     Causes the step command to display the source code  corresponding
     to the current program location.  This is the default.

     Opposite of /NOSYSTEM.  /SYSTEM, which  is  the  default,  simply
     says  that  DEBUG  should  feel  free  to step into called system
     services.  (DEBUG actually just identifies a  system  service  by
     its  address  being in P1 space.  So "SET STEP NOSYSTEM" prevents
     you from stepping into any routine whose address is in P1 space.)

     DBG> SHOW STEP
     step type: source, nosilent, by line,
                over routine calls
     DBG> STEP   ! step one source line
     stepped to EIGHTQUEENS\TRYCOL\%LINE 44
         44:    i := 0 ;
     DBG> STEP 3 ! step three source lines
     stepped to EIGHTQUEENS\TRYCOL\%LINE 48
         48:       if safe then
     DBG> SET STEP INST
     DBG> STEP   ! step one instruction
     stepped to EIGHTQUEENS\TRYCOL\%LINE 50: MOVL    FP,R1
         50:          setqueen ;
     DBG> STEP/RETURN ! step to the end of the routine
     stepped on return from EIGHTQUEENS\TRYCOL to
       EIGHTQUEENS\TRYCOL\%LINE 59: RET
         59: end ; (* trycol *)