00100	*****  SIMPLE-MINDED GUIDE TO DDT FOR SIMPLE-MINDED PROGRAMMERS *****
00200	
00300	TO LOAD WITH DDT:
00400	
00500		"LOAD %DNAME1,NAME2,....." (the program names)
00600	
00700	TO SET BREAK POINTS:
00800	
00900		In order to stop a program at selected points up to  8  break
01000	points  may be set.  The break points may be set at any FORTRAN label
01100	number - or in between labels.  The only restriction  is  that  break
01200	points  cannot  be  set  at  subroutine  calls.  (Note that sometimes
01300	FORTRAN creates its own subroutine  calls,  as  for  example  when  a
01400	floating point number is changed to fixed point.)
01500	
01600	To set a break point at label 10 in a program type as follows:
01700	
01800	 	"CALL" (=cntrl C)
01900		"DD" <cr>
02000		"SUBR$:" (Puts you in subroutine SUBR.   To get into the main
02100			  program type "MAIN.$:".)
02200			  ($=ALTMODE) The cursor will now jump.
02300		"10P$B"  (The break point is now set. 
02400			  The "P" is always necessary with FORTRAN labels.)
02500	
02600	Now to start the program type "$G" (use <cr> only where indicated.)
02700	
02800	The program will automatically stop at label 10.
02900	
03000	The contents of the variables may now be examined.   There  are  many
03100	print-out modes available.  Only one will be mentioned here.
03200	
03300	To  print  ordinary  decimal  numbers first type "$$10R" (=radix 10),
03400	then "$$F".  This last is for floating point  numbers  but  it  works
03500	also for fixed point.
03600	
03700	Now  to  check  any item just type "N/" where N is the variable to be
03800	examined.  The current state of N will immediately appear.
03900	
04000	If you are looking at an array such as P(1) through P(30), to see the
04100	first  location of the array type "P/", to see P(2) type "P 1/" (here
04200	a space is equivalent to "+"), for P(14) type "P 13/", etc.
04300	
04400	To  look  at several successive steps of the P array, type "P/", then
04500	"LINE" (=line feed) for the following locations.
04600	
04700	To cause the program to continue running type "$P"  (=proceed).   Now
04800	it will go on until it hits another break point.
04900	
05000	If you wish to take out the break points, type "$B" before "$P". 
05100	"$G" will restart the program from the top.
05200	
05300	If  you  wish  to  set  a break point with automatic type-out add the
05400	desired variable in parentheses.  To have N print each time we get to
05500	label 31 type "31P(N)$B"
05600	
05700	To  set  a  break point just before label 55 type "55P-1$B".  Now the
05800	program will stop at the last instruction before 55.  "55P 3$B"  will
05900	stop  on the third instruction after 55, etc.  (Note that one line of
06000	a FORTRAN program usually creates several instructions.)
06100	
06200	***** For further information see the DDT manual. *****