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SIMULA.DOC -- Changes from version 3(120) to version 4A(310)
July 1978

Copyright (C) 1975,1976,1977,1978
Swedish Defence Research Institute, Stockholm, Sweden

1.0	SUMMARY

1.1	This  release  introduces  some  new  features  and  includes
	corrections  to  all  but  a few known bugs or problems. This
	version has no new deficiences and fully replaces version 3.

1.2	SIMULA  is  documented in the SIMULA Language Handbook, parts
	I, II and III, available from the  Swedish  Defence  Research
	Institute  (FOA),  S-104  50 Stockholm 80, Sweden.        The
	handbooks are also available  on  the  distribution  tape  in
	RUNOFF format.

1.3	The distributed version of SIMULA is developed  for  a  KI-10
	processor.         It  will  also  run  on a KL-10 processor.
	A KA-10 version is available from the University  of  Western
	Ontario,  Computing  Center,  London  72, CANADA.        This
	version  is  however  currently  not  quite   up   to   date.
	SIMULA  runs  on all supported monitors starting with 5.06. A
	few library procedures rely on UUO's available only  on  5.07
	or 6.01 and upwards.

1.5	The  following standard system file must be used when setting
	up SIMULA:

 	HELPER.REL

1.6	User information may be found in section 2.0 EXTERNAL CHANGES
	and section 3.0 KNOWN BUGS AND DEFICIENCES.

2.0	EXTERNAL CHANGES.

2.1	Changes from 3A(206) to 4A(310): - A number of "Illegal memory
	reference" errors have been corrected, mostly occurring in
	large programs.
	- SIMDDT:  The DISPLAY, USE and @  (indirect  command  file)
	commands  can  now  be  used  in  almost any situation, e.g.
	following ^C-REENTER.  The syntax of the DISPLAY command  is
	more convenient.  Control characters like form feed (^L) are
	displayed in "arrow mode".
	If a program has turned off  echoing  of  input  characters,
	SIMDDT will turn on the echo while it is active.
	INSPECT/START repeats the reason for entering SIMDDT.
	- Random Drawing:  NORMAL and POISSON  now  give  antithetic
	drawings,  e.g.  Normal(a,b,u1)+Normal(a,b,u2) = 2*a if u2 =
	-u1 initially.  Only the used random  drawing  routines  are
	loaded from SIMLIB.REL.
	An error in the Normal distribution has been corrected.
	- New RTS high segment and SIMDDT file names: SIMR41, SIMR42,
	SIMDD4.   The  old  files  (SIMR21,  SIMR22, SIMDDT) must be
	retained if old .SAV or .EXE files from SIMULA programs  are
	to  be  run.   Reloading is recommended to take advantage of
	the new features  and  corrections.   Recompilation  is  not
	necessary but is recommended.
	- Extension .SIM is now tried first if no extension is given
	when  running the SIMULA compiler directly via the R command.
	Previously, a null extension was tried first.
	-  Compiler  and run time system, as well as SIMULA programs,
	can now be run with protection <666> (execute only).
	-  Lines  starting with "%" (percent sign) are ignored by the
	SIMULA compiler in anticipation of changed syntax of  OPTIONS
	statement.   Also   makes  it  easy  to  insert  preprocessor
	directives in source code.
	-  The  SIMULA  RTS  now  accepts  special  characters in the
	"FILE.EXT"  part  of  a  file  specification.   The   special
	characters  are  coded  in  octal  sixbit,  preceded by a "#"
	character. The whole or part of FILE and/or  EXT  can  be  so
	specified.  See  PIP, which has the same convention. Example:
	"#000100000200.UFD[1,1]" is the directory of [100,200].
	-  Default  LINESPERPAGE(-1)  for  Sysout  if  it  is  on the
	terminal. No free page skips.
	-  PTY  (subjob)  control available in LIBSIM. See SIMLH3.MAN
	and LIBSIM.HLP. Not fully checked out!!!
	- SIMDDT: INPUT t:-u now works (texts).

	- SIMRTS: It is now possible to load a SIMULA program in  the
	high  segment, leaving room for more data in the low segment.
	Loading is done according to the following example ('A stands
        for the	name of the program):

	.R LINK
	*/SYMSEG:NONE	;Avoid local symbols
	*'A.MAP/MAP	;Not necessary, but may be useful
	*SYS:SIMLIB/INCLUDE:(OCSP) ;(1) Must be in low segment
	*/SEGMENT:HIGH REL:SIMHGH ;Must be first in high segment
	*/SEGMENT:HIGH 'A	;(2) Your REL files here
	*/SEGMENT:HIGH SYS:LIBSIM/SEARCH ;Any LIBSIM modules here
	*/SEGMENT:HIGH SYS:SIMLIB/SEARCH,REL:HELPER/SEARCH
	*/G
	.SAVE 'A

	Notes:
	(1) If the main program is loaded in the  high  segment,  the
        high  segment  will  NOT be write-protected. Otherwise, it is
        not possible to change the high segment. In that case, SIMLIB
        library  modules such as ALOG. which are not reentrant should
        be loaded explicitly in the low segment, also  other  modules
        which  are  changed  during a run. It will not be possible to
        set SIMDDT breakpoints in  a  write-protected  high  segment.
        Protection    may    be    set    off    via   SETUWP   (E.g.
        XCALLI(8R36,0,TRUE,-1), see SIMLH3.MAN, LIBSIM.HLP).  If  the
        LIBSIM  procedures  SAVE,  RUN or FREEZE should be used, load
        them in the low segment (FREEZE must be in  same  segment  as
        SAVE).
	(2) If you want to put most  of  your  program  in  the  high
        segment,  but not the main program, just make the bulk of the
        program an external class and use it as prefix  to  the  main
        program  which can be simply: BEGIN <external decl>; EXTERNAL
        CLASS mainprg; mainprg BEGIN END END;
	The  main program itself can then be loaded either in the low
        or the high segment.
	- All SIMDDT I/O can be directed to another terminal:
	Just give the SIMDDT commands
		*USE TTYxx:
		*@TTYxx:
	where xx is the tty number of an available tty connected to
	the system (directly or via modem).
	The SIMDDT commands and SIMDDT output will not interfere with
	your controlling terminal. Useful if you are testing special
	display terminal handling.

	Edits 301 - 310:
	SIMULA  compiler  -  Less  frequent  changes  in  ATR  files.
        Addition of a FOR loop and similar changes no  longer  affect
        ATR file.
	SIMDDT/SIMRTS - Open USE, DISPLAY and indirect command  files
        at  EXIT  no  longer give error message. Closed automatically
        like SYSIN and SYSOUT. If  the  USE  file  and  the  indirect
        command  file  both are another TTY than the controlling one,
        direct ALL SIMDDT output ordinarily sent to  the  controlling
        TTY  to  the  other  TTY  instead, thus completely separating
        debugging i/o  from  program  i/o.  Allow  digit  immediately
        following SIMDDT command, as in D100 (=DISPLAY 100).
	TOPS-20 SIMULA corrections, mainly file spec handling.
	REL files no longer contain type 17 loader blocks, only ASCIZ
        command strings.
	LIBSIM: Some corrections, e g to RENAME.MAC.

2.2	Changes from version 3 to 3A:

	- Much better performance if a SIMULA program goes virtual.
	- SIMULA can now be run under a default path different  from
	the  UFD.  The path may contain SFD-s (sub-file directories)
	to an installation-dependent  level (at  most  6,  including
	the  ppn).   See  the  SETSRC  program and the MONITOR CALLS
	manual.
	- Better ARCTAN in double precision adapted from  new  DATAN
	for FORTRAN.
	- An error in NORMAL and POISSON is corrected.
	- Full path specifications  are  now  allowed  on  all  file
	specifications  handled  by  the  compiler  -  REL file, ATR
	files, LST and source files, and the file  spec  in  the  /R
	switch.
	Example:   Assume  that  your  UFD   is   [12,34]   .COMPILE
	x.sim[,,a,b]  will make SIMULA compile the file x.sim in the
	path [12,34,a,b] and place the REL file on your own  default
	path, which may be different from the UFD.
	- The search for  ATR  modules  in  the  compiler  has  been
	optimized, avoiding excessive I/O operations by reading each
	library only once.
	-   When   compiling   a   global   procedure    or    class
	[OPTIONS(/E ...)],  a  matching  ATR  module  is  looked  up
	according to the search list set by the SEARCH switch to the
	compiler.   If  a  matching  module is found in a library, a
	copy is made to the same area as the REL file, so  that  ATR
	and  REL  files  nearly  always are in corresponding places,
	even if no changes are made in  the  ATR  information.   One
	backup  level  of  ATR  modules is maintained - the old file
	gets the new extension QTR.  This makes it easier to "change
	your mind" if you find that your last change was not useful,
	and you want to recover the old version.
	- The HIDDEN PROTECTED feature is somewhat changed from  the
	release  3 implementation - if the PROTECTED identifier x is
	declared in several subclasses, HIDDEN x will hide only  the
	innermost  visible  x,  which  then becomes invisible to the
	next inner level, where the next outer x can be hidden, etc.
	- It is now  possible  to  access  the  procedure  value  in
	SIMDDT.

			     [End of 3A changes]

2.3	Changes introduced in version 3:

	- The HIDDEN PROTECTED feature has been implemented.
	- New facilities have been  added  to  SIMDDT.   It  is  now
	possible  to  continue  processing  after  some errors.  The
	CLOSE, NOPROCEED  and  @  commands  have  been  added.   The
	NOARRAY  command  has been removed but the switches /-ARRAY,
	/-TEXT and /-GC may be used to reduce the output.  THIS  and
	QUA  are accepted in an identification.  Complete blocks can
	be output with the *  feature.    ^C-REENTER  will  end  the
	processing  of  the  current  SIMDDT command.  The VARIABLES
	command will also output TYPE PROCEDURE values.  Any control
	character  x  in  a  TEXT  variable is replaced by ^<letter>
	(e.g. ^L for formfeed, Char(14))  when  SIMDDT  outputs  the
	variable value.
	At end of execution only the  SYSIN  and  SYSOUT  files  are
	closed  automatically.   An  error  message will be given if
	other files are open.  The new SIMDDT command CLOSE  may  be
	used to close the files.
	- Changed syntax of text constants:  Long text constants can
	now  be  written in several parts, which may be separated by
	spaces, tabs or line control characters.  Example:
	    t:-Copy("first part" "second part"
	     "third part");

			[End of release 3 information]

2.4	Release 2 information:

	- ATR files as  well  as  REL files  generated  by  the  new
	version  can  be  members of a library (see /FUDGE switch to
	COMPIL, FUDGE  command  and  FUDGE2  program).   Loading  of
	SIMULA  programs  has  been simplified.  If some conventions
	are observed, only the main program name need  be  mentioned
	once  external  classes and/or procedures have been compiled
	and possibly put into libraries.
	LIBSIM.REL  and  LIBSIM.ATR on SYS: contain  useful  classes
	and  procedures.   ATR  files are automatically looked up in
	SYS:LIBSIM.ATR if not found on your  own  area  as  separate
	files  or  in  a  library  (default LIBSIM.ATR).  LINK-10 is
	directed to look up the REL-file in the corresponding  place
	(extension ATR replaced by REL).
	See /SEARCH switch in SIMCOM.HLP.
	Old SIMULA files referring to ATR  files  on  SYS:   ([1,4])
	should  be  edited  not to contain any such reference, since
	SYS:libsim.atr will be searched in the normal case.
	Warning!  Old REL files are still valid, but old  SAV  files
	can  only  be run as long as the old runtime system segments
	SIMRT1.SHR and SIMRT2.SHR are available  on  the  SYS  area.
	SIMDD1.ABS may also be needed by such programs.
	The new runtime system segments are  called  SIMR21.SHR  and
	SIMR22.SHR.
	New facilities  have  been  added  to  SIMDDT.   It  is  now
	possible   to   display  lines  in  the  source  code  while
	debugging.
	New SIMDDT commands:   DISPLAY  and  INSPECT.   For  further
	information do .HELP SIMDDT.

	               [End of release 2 information.]

3.0	KNOWN BUGS AND DEFICIENCIES

Compiler errors:

	-  OPTIONS(/A);  a[1]:=a[n]; OPTIONS(/-A); will unfortunately
	NOT check the array bounds [1:n]  of  a,  since  the  lexical
	scanner  is  ahead  of  syntax  analysis  and  turns  off the
	checking before it can be applied. This is remedied by simply
	adding another ; after the assignment - a[1]:=a[n];; OPT... A
	similar argument applies to the Q switch.

	- A virtual match may be "lost"  in  circumstances  like  the
	following (E223):

A.SIM:	OPTIONS(/E); CLASS a; VIRTUAL:PROCEDURE vp;
	BEGIN vp END;
B.SIM:	OPTIONS(/E); EXTERNAL CLASS a;
	a CLASS b; BEGIN PROCEDURE vp;; END;
MP.SIM:	OPTIONS(/S:"AB"); EXTERNAL CLASS a,b;
	b BEGIN END;
AB.ATR:	This ATR library contains attribute modules for classes a and
	b in REVERSE order.
AB.REL:	Contains object code for classes a and b.

	When compiling MP.SIM, no match for vp will be found, leading
	to  a  run  time error.  This occurs since the compiler reads
	attribute files as they are found  in  the  attribute  files,
	i.e.   first any separate ATR files (not libraries) are read,
	then modules from the libraries in the search  list,  in  the
	order  in  which  they  occur  in  the  libraries.   When the
	attributes of b are input, no reference to vp  has  yet  been
	seen,  so  the  declaration  is  omitted from the declaration
	structure sent to pass 2 of the compiler. This "optimization"
	works for anything but virtual quantities. The problem occurs
	only when virtual quantities  are  involved  in  an  external
	prefix  chain,  and  only when the classes are treated in the
	wrong order. If the ATR files for a and  b  are  separate  or
	occur  in  the  correct order, no problem arises. The problem
	also vanishes if there is a reference to a  virtual  quantity
	in  each  class where a match is declared. This reference may
	be of the form IF FALSE THEN vp; to avoid execution of vp.

	- A missing  NEW  before  <class-identifier>  is  not  always
	diagnosed and may lead to an obscure run time error. Example:
	CLASS a(i); INTEGER i; ...;  a(17);
	The  erroneous  statement  "a(17)" is treated as if it were a
	procedure call, and no message is issued by the compiler.  If
	the  class  has no parameter, an error message is issued, but
	it is misleading.    The  error  is  diagnosed  correctly  if
	a(...) is used in an expression, not as a statement.

	- Bad error  message  in  a  case  like:
	BEGIN  ...
	  BEGIN  EXTERNAL PROCEDURE ep; ... END;
	    ...
	  BEGIN  EXTERNAL PROCEDURE ep; ... END;
	  ...
	END;
	The second EXTERNAL specification for ep leads  to  an  error
	message: FILE NOT FOUND EP.ATR
	Remedy:
	Move EXTERNAL spec outside both blocks (to outer level).

	Run time errors:

	- If a terminal other than the controlling tty  is  used  for
	SIMULA  i/o,  a  ^C on the terminal leads to the error ZYQ054
	TRANSFER FAILURE. Do not use ^C in those circumstances.

	- If the run  time  system  is  asking  for  additional  file
	information  to be able to access a file, an altmode (escape,
	Char(27)) will  cause  SIMDDT  to  be  invoked.  Do  NOT  set
	breakpoints  ([STOP]  AT  ...)  in this case. Run time errors
	will result when you proceed from SIMDDT.

	- ^C-REENTER with  executable  files  saved  via  the  LIBSIM
	procedures  SAVE or FREEZE will not work with new releases if
	they were saved before release 4(300).

4.0	Details of changes - version 3 to version 4:

4.1	Recent changes following release 4(300):

[301]		Pass3:M3.MAC<M3ATR>
		Ignore ZHBSZD when comparing new and old  ATR  files.
		No new ATR file need be created just because the size
		of the display vector changes, e g because of  a  new
		subblock, inspection, FOR loop or thunk save area.

[302]		SIMRTS:IO.MAC<IOCLA>  -  Handle  SIMDDT   USE   file,
		indirect  command  file  (@ command) and DISPLAY file
		like SYSIN and SYSOUT, i e allow them to be  open  at
		program  exit  and  close  them automatically without
		error messages.

		-   IO.MAC<.IOCL>  -  Correct  an  error  leading  to
		premature RELEASE of a TTY channel when  it  is  used
		for  both  an Infile and an Outfile. This led to "I/O
		to unassigned channel".

		- OCIN.MAC<SYSIN/SYSOUT initialization>  -  Change  a
		test  to  allow  SYSIN  to be assigned to another TTY
		than the controlling one. Note  however  that  ASSIGN
		TTYn SYSIN and ASSIGN TTYn SYSOUT will not work, only
		the last ASSIGN remains in effect. A  common  logical
		name  for  both  SYSIN  and  SYSOUT  device  would be
		needed.

		SIMDDT:SIMDS9.MAC<DSCMI> - If  the  indirect  command
		file (@ command) is a TTY, output the prompter (*) on
		that TTY.

		- SIMDS2.MAC<DSOxx> - If the  file  given  in  a  USE
		command  refers  to  a  TTY  device  other  than  the
		controlling TTY, direct  all  "TTY"  output  to  that
		terminal,  and  none  to the controlling TTY, even if
		output to both TTY and USE  file  is  requested.  The
		procedure  DSOTTC  checks for that case and is called
		from several of the DSOxx routines.

[303]	(E250)	SIMRTS: TX.MAC<TXGR> - Move label TXGR4: so that sign
		of  number  is  not lost if Lowten character is found
		but no exponent part follows, not even a sign.

[304]		SIMDS1.MAC (MDSGIK  def),  SIMDS2.MAC<DSTCL,  DSGIK>,
		SIMDS9.MAC<DSCM>:   Allow   digit  immediately  after
		SIMDDT command keyword (no space  necessary).  SIMDDT
		command keywords do not contain digits.

[305]		Changes for TOPS-20 SIMULA v4 to work.
		OCSP.MAC Do not check for zero hiseg name in TOPS-20
		version.
		OCIN.MAC Some corrections: GETSPEC, OCINGD  (save X3
		also)
		Dummy argument for L4 macro before "]".
		OCIO.MAC <IOTYSP>: Use PPNST%, not DIRST (TOPS20 only).
		V1B.MAC - Rewrite PPNST., DIRST. to use SOUT and BOUT.

[306]		Correct error with ASCIZ commands in REL file:
		LOWSEG.MAC  Add variables YO1ASB (2 words), YO1ASC to
		keep track of ASCIZ strings in REL file.
		O1.MAC<O1RLOP>  Clear  bookkeeping  words  for  ASCIZ
		strings.
		O1.MAC<O1SFDC>  Do  not  rely  on YSFDN when copying,
		count!
		<O1RLRQ>  No  request  block  (type  17),  only ASCIZ
		strings.
		<O1RLOA>  If  the currently last word in the REL file
		buffer is the last word of a command string,  restart
		there,  adding a comma and putting the current string
		immediately after.

[307]		LIBSIM - FREEZE.MAC<.ZYLSJ>: Save hiseg  lookup  data
		only once to avoid problems on repeated calls.
		INLINE.SIM: Change to conform with specification.
		FORSIM.SIM: Add entry "FIN.".

[310]	(E254)	LIBSIM - RENAME.MAC: Update channel  table  correctly
		so  that  Close (IOCL) will release the proper entry.
		Also correct an erroneous zeroing of  YIOCHT(0),  and
		clear buffer header pointers before dummy Open.

4.2	Changes from 3(120) to 4(300):

	These changes include adaption to DECsystem-20: Edit [225]

[120]	(E133)	SU <.SUCA, .SUHO> Cancel(x), where x.Idle  EQV  TRUE,
		was  not  implemented  according  to the Common Base,
		which implies no action in that  case  (EVENT==NONE).
		Correction:  If zpszev  =  0,  return  directly.  For
		safety reasons the same modification was made in SUHO
		(Hold).

[121]	(E135)	TXBL  <TXVA>:  Check  for  too  long  RHS  same   for
		LHS==NOTEXT  as  for other LHS values. The stack must
		be balanced when continuing.

[122]	(E137)	OCEP  <.FORER>:  Load  X0,  not X2 with error UUO for
		faked APR error in FORTRAN subroutine, e.g. the error
		occurring for EXP(89) - faked overflow.

[123]	(E142)	OCEP <.OCUU>:   SETOFF SWNOGC(XLOW)  when  PROCEEDing
		from SIMDDT after an error with recovery specified.

[124]	(E149)	LIBSIM:  UPCASE.MAC, LOWCASE.MAC - t.Setpos(1) before
		assignment  to  function  result.  Change   also   in
		SLH35.RNM.

[125]	(E150)	LIBSIM:  SEARCH.MAC - Extend byte pointer table  ptab
		to include one more item.  Failed when config started
		with last character of a word.

[126]	(E152)	LIBSIM:  INPUT.MAC  -  Correct  handling  of TEXT and
		ARRAY attrib. Also change  end-of-file  treatment  to
		avoid error messages.
		LIBSIM: OUTPUT.MAC - Ensure  correct  word  count  by
		modifying  the  byte  pointer  to  point to last word
		written.

[127]	(E154)	SIMULA.SHR:    SYS1.MAC    -    Simulate    PROTECTED
		specifications   for   attributes   of   SIMSET   and
		SIMULATION:
		LINKAGE, LINK, HEAD, PROCESS,  CURRENT,  TIME,  HOLD,
		PASSIVATE, WAIT, CANCEL, ACCUM, MAIN.
		Thus they can be HIDDEN in subclasses.

[130]	(E159)	LIBSIM: INPUT.MAC - Catch illegal parameters, such as
		constants, and give error messages.
		LIBSIM: OUTPUT.MAC - ZDFLIM calculation corrected.

[131]	(E160)	SIMRTS: PH <PHFT> - Handle text procedure correctly.

[132]	(E148)	CA <SWEND> Declaration stack reset to the same  value
		as at entry of OR<SWITC>.

[133]	(E141)	ORRK <ORRP,ORRPIV> Allow the value of a parameterless
		system  procedure  to  be  passed as a parameter to a
		formal or virtual procedure.

[134]	(E119)	OR<OREN>  ORRK<ORTY> Check if identifier after NEW is
		a CLASS even if it has parameters.

[135]	(E161)	LIBSIM:FREEZE.MAC - Save LINESPERPAGE and SPACING for
		Sysout over CLOSE and OPEN.

[136]	(E100)	CARL,CA<CADS>  Make  doubly declared class attributes
		undefined as is done in blocks.

[137]	(E170)	LIBSIM:SAVE.MAC -
		1) Change test for size of buffer area.
		2)  Return  with  function value = -1 if some file is
		not closed.

[140]		O2SA <O2GVIN>
		CA   <CAEBVM,CAUNPR>
		SIMMAC<ZQUUSE>
		Implement new variant of [NOT] HIDDEN.

[141]	(E177)	OCEP <.FORER>: Handle simulated underflow (as in EXP)
		like real underflow.

[142]	(E180)	LIBSIM:CONC.MAC - Handle parameter-less function proc
		correctly.

[143]		LIBSIM:insinglechar  - error corrected for input from
		DSK.

[144]		Affects  SIMMC1,  LOWSEG, DP, O1, SD, SR, I1, LC, LS,
		CA, E3, T3, I3
		1) Optimize ATR file handling in PASS 1.
		2)  Introduce  full  SFD  path specifications for all
		files treated by SIMULA -  REL,  LST,  SIM,  ATR  (in
		external decl), /S switch, /R switch.
		SFD paths for files to be loaded are written as ASCIZ
		strings       in       the       REL      file      -
		"dev:file[proj,prog,sfd1,...]/SEARCH".
		3)  Use /SEARCH list also for the ATR module produced
		with OPTIONS(/E).
		4)  If the matching ATR module is found in a library,
		copy it as a separate ATR file to the  same  area  as
		the  REL  file.  If an old ATR module existed, change
		its extension to QTR,  after  deleting  any  old  QTR
		file.  This  leaves  one  backup  with the old unique
		identifiers which can be used if the  changed  module
		was not satisfactory.
		5) In the RTS, module IONF: .IOLOK/.IOENT - Save  SFD
		pointer  over  LOOKUP/ENTER and restore it afterwards
		in any case. This makes it possible to REOPEN a  file
		defined with an SFD path.
		OCIN <GETSPEC> Allow missing fields like  [,4],  [,],
		[13,]. Supply missing information from UFD (logged-in
		ppn). Allow the notation [-] for the default path.
		OCIO <.IOTYSP> - If default path, type [-], not [,].

[145]	(E???)	SIMLIB: PHPT.MAC<PHPTSR,PHPTGR> Save and restore ac's
		correctly  when  passing  text  or  array by value to
		formal, virtual etc procedure.

[146]	(E184)	CGRK   <.QUAL>   Fetch   qualification  from  correct
		location if ARRAY.

[147]	(E140,E171,E176)  O2RK  <O2IC2Z>  No  zero fill of IC2 buffer
		when it is already full.

[150]	(E186)	LIBSIM:PACK.MAC   -   Save  XPBYP=XUTYP  over  PUSPV.
		Spurious errors when "type" changed in PUPI.

[151]	(E106)	SIMDDT (SIMDS7, DSNI and DSLPR) 
		SYSIN and SYSOUT now visible from external module.
		The  PROCESS,  LINK  and HEAD classes can now be used
		after QUA in a SIMDDT identifier.

[152]	(E120)	SIMDDT (DSVA) A switch prototype has no symbol table.


[153]	(E126)	SIMDDT  (DSDP)  HELP  command  corrected.  Old  input
		zeroed.

[154]	(E138)	Also  (E145)  and  (E175).  SIMDDT  (DSGL,  DSPCL and
		DSPVS) If no line that corresponds to  the  interrupt
		is  found  SIMDDT  will  now  assume that the current
		module is MAIN. Several tests for this case have been
		added.
		OUTPUT * will now display the current block  even  if
		it is not found in any line number table.

[155]	(E139)	SIMDDT (DSDP) A  line  number  with  more  than  five
		digits  will  now  be  cut  in the same way as by the
		compiler.

[156]	(E143)	SIMDDT  (DSBP  and SIMDS1) Control C REENTER commands
		which occur  when  SIMDDT  is  processing  breakpoint
		command  code  will now cause SIMDDT to stop and give
		control to the user.


[157]	(E147)	SIMDDT  (SIMDS7)  Processor flags are not restored by
		SIMDDT after a breakpoint has been handled.  This  is
		not  needed  but  it  was  done  in  an erroneous way
		before.


[160]	(E157)	SIMDDT  (DSINE  and  DSPR)  The  error  ZYQ212 is now
		treated specially in SIMDDT. It  makes  SIMDDT  enter
		debug mode and allow all commands.

[161]	(E163)	PHPT <CHECK SAMETYPE> Do not destroy AC0.

[162]		Make  sure  internal  compiler  files are found where
		they should be, i e on the default path  (zero  ppn),
		which  is  not always equivalent to the logged-in ppn
		(UFD).
		O1<O1OPIC,O1OPLS,O1RLOP  etc> ppn reset to zero after
		ENTER on temporary files, reset to given path for REL
		file.
		O2SA same for IC2.
		O3 <O3ATR> Reset YELATR+3 before lookup.
		Final REL and LST file names from the start (no TMP).
		Close REL file without creating a new REL file if not
		wanted.
		NUL: device for REL file if no file spec given, but =
		given. This makes the /NOBINARY switch to COMPIL work
		for SIMULA.

[163]	(E79)	SIMDDT  (DSPLE) SIMDDT now checks if the current line
		number and the XCB pointer  are  consistent.  If  not
		SIMDDT  checks  if the calling block is ok, otherwise
		it terminates the processing.

[164]	(E130)	LS pass 1.  Check first character after " " in string
		processing.

[165]		LIBSIM:FREEZE.MAC   -   Take   core  allocation  from
		.JBCOR<LH> in .ZYLRJ.

[166]	-	SIMDDT changed to allow output and input  of  a  type
		procedure  value. (DSNI, DSPI, DSLV,DSAT, DSIP, DSCM,
		DSCSQU, DSPV, SIMDS1 and SIMDS7 changed)


[167]	(E181)	IONF<SETUPFILE>  Treat  NUL:  as  device without file
		name.

[170]	(E173)	E3	<E3ERR> error  message  before  first  source
		code line.

[171]	(E124)	LC main <CR><LF> after <FF> in line numbered file

[172]		SIMMAC <SWAPPA> In SYS version, try to get  passes  2
		and  3  from  same  area  as  pass  1, otherwise SYS:
		Affects  modules   I1,T1,I2,O2SA,I3,T3,   which   use
		SWAPPA.

[173]		EX <EXQC> Zero line number (X5) for error message  in
		case no matching declaration exists.

[174]	(E113)	CGOB	<CGAS>
		OR	<DENOT.,DEQ.,NDEQ.>
		ORRK	<ORDT,ORRPPP,ORRPIV,ORTXCH>
		Restrict usage of conditional text constant.

[175]	(E185)	SA
		Improved performance of storage control when job goes
		virtual.
		- Save X3 in .SACL
		- Print number of page faults between and during GC:s
		(only niw faults recorded) when program ends.
		-  At start of GC, save number of niw faults in YSABH
		and number of niw faults  since  last  GC  in  YSASW.
		GETTAB  [13,113] used. Cumulative count of niw faults
		updated in left half of YSAIBP.
		-  .SAGI  (initialization) Job's cumulative niw fault
		count to YSABH.
		-  SANP1  If  first CORE fails, check if job is going
		virtual, and if it does, subtract space (1K) for PFH.
		GETTAB [-1,,102] used.
		- SANP If job is virtual,  determine  number  of  niw
		faults  between last two GC:s (from YSASW) and change
		YSAL by 2K*SIGN(tgc-tswap*(nb+2*ng). Here
		nb	niw faults before last GC;
		ng	niw faults during last GC;
		tswap	time  (ms  cpu)  accounted  for  a  page swap
		(currently ^d20);
		tgc	time spent in this GC.
		However, if YSAL becomes less than  minimal  quantity
		needed, the latter is passed to SANP1.
		- SANP If job is not virtual, but the  new  estimated
		optimal YSAL value will make it virtual, make the new
		YSAL  value  so  that  the  job  just  goes   virtual
		(YSAL=min(physlim+qpolmi,virtlim)-YSAHSZ-sizeofPFH).
		GETTAB  [-1,,102]  is  used  to  find  out   physical
		limit/guideline.

[176]	(E72)	DP	<DPEXCR,DPSYS>
		CA	<BPROG.>
		Allow  externals  to have same name as system-defined
		classes and procedures.

[177]	(E182)	OCIN	(SYSOUT object setup)
		Check  if  SYSIN is on same in-out device (normally a
		terminal).  Use same channel as  SYSIN  if  so,  with
		both output and input buffers.
		OCIN	(LOOKUP on specification file)
		Copy  lookup  information  to buffer before LOOKUP in
		order  not  to  destroy  it.   Program  can  then  be
		restarted by START correctly.

[200]		IO	<IOCL>
		If the tty infile has ENDFILE TRUE, do an OPEN UUO to
		allow  continuation  after SIMULA Close and following
		Open.

[201]		OCIO <GETCHANNEL> Return -1 if no  channel  available
		and ZFIFND bit set.
		IONF  <SETUPFILE>  Do  not  clear   file   name   for
		non-directory  dev.  Gives  correct  spooled name for
		LPT:, CDP: etc.

[202]		I1, LC, SD, CGRK, SU.MAC: Avoid 6-character names  in
		parameters  to  SAVE macro - MACRO v.50 bug. Found by
		Ken Roberts, UWO.

[203]		LOWSEG.MAC -  Use  LOC  instead  of  RELOC  in  debug
		version. Due to Ken Roberts, UWO.

[204]		T3.MAC <T3ID> New secondary entry to T3I. Called from
		T3R to delete IC2 file for Macro/Fortran headings.

[205]		RD <.RDER,.RDNE,.RDNO,.RDPO>
		Modify  calls to mathematical routines. This corrects
		an error in NORMAL and POISSON, which call SQRT.  The
		earlier  version  allowed the parameter to SQRT to be
		changed within SQRT, leading to erroneus  values  for
		the  variance  of the NORMAL distribution (about half
		of correct value), and  similar  error  for  POISSON.
		This  applies  to  SIMLIB libraries which contain the
		new improved SQRT from the start of 1976.

[206]		LIBSIM:SAVE.MAC - Correct return if save  file  could
		not be opened/entered.
		LIBSIM:SAVE, RUN - Avoid messages.

[207]	(E127)	OCIO <.OCIND> (LINKBUFF)
		Use  bit  in  buffer ring is now set to 0 with SETOFF
		ZBUUSE to permit reusage of buffer area.

[210]		DP <DPEXT> Do NOT set ZQUSYS bit for QUICK proc.
		CGSA  <ZID.>  Error message ERROR1 15 - test also for
		ZHBMQI.
		SIMLH2.MAN,  SIMERR.ERR  -  SIM347 message changed to
		show QUICK.

[211]	(E194)	LIBSIM:PACK.MAC<PUPI> Correct  initialization  of  XB
		(due to Mark Legg, Flinders Univ, S Austr).

[212]	(E225)	SIMP2: CGPA.MAC<CGNN> - Correction of code generation
		for passing a NAME parameter on to a formal parameter
		which  is  also  specified  NAME.  The  top ac number
		should be in the offset field  of  the  byte  pointer
		used, not the index field.

[213]	(E224)	SIMDDT - SIMDS9.MAC<DSAT>.
		Wrong info stacked when calling DSRLBA at L1()  after
		getting an incorrect line identification in [STOP] AT
		command. If this is the first such  command,  no  ZBR
		has  been  allocated,  so  should not be removed. Now
		indicated by checking  YDST3  for  zero  (set  before
		trying to read line id).

[214]	(E220)	Pass  2  - CARL.MAC<CARLVI>.  Check for qualif YUNDEC
		and accept  as  correct  (error  msg  for  undeclared
		qualif already issued).

[215]	(E222)	Pass  1  -  DP.MAC<DPMAP>.   Make sure whole map (ZMP
		record) is zero for EXTERN:CODE.  ZMPDTX  was  always
		2,  which  gave errors on g.c.  inside CODE procedure
		(probably very rarely, no specific instance found).

[216]	(E217)	Pass 2 - OR.MAC<ORCPR>.  Check for  type  REF  before
		checking any qualtion.

[217]		SIMMAC.MAC, Compiler pass 1:
		Take version number from  .JBVER  and  edit  it  into
		heading  rather  than  define  it  explicitly  in the
		VERLST macro.
		SIMMAC.MAC:  Move VERLST, $HDVER and $HDV10 macros to
		E3.MAC.
		E3.MAC: Also add the new routines E3NOUT and E3PVER.

[220]		Modification  of  [162] to make it really work. If ^Z
		ends a command line, treat it as end of
		line,  obey  the  command  and  then  EXIT to monitor
		level. Affects I1, T3 and SIMMAC (YSWCZ definition).

[221]		In  all  universal  files  (SIMMAC.MAC  etc),  insert
		.DIRECTIVE  .NOBIN  to  avoid creation of a REL file.
		This is only done  if  the  .directive  pseudo-op  is
		defined  -  implies  at  least  version  50 of MACRO.
		Define RET and XEC by OPDEF. They are  shorter  forms
		of RETURN and EXEC with no overhead.

[222]		O3.MAC:  Make  sure  ATR file gets correct protection
		and creation date: Same  prot  as  old  separate  ATR
		file,  same date and std prot if copied from library,
		std prot and new creation date if all new.

[223]		Use PUTREL instead of GENABS in  O1RLAS  (O1.MAC)  to
		avoid  automatic  generation  of  relocation  word in
		ASCIZ string.

[224]		Output of messages in mixed case in OCIN, IONF.

[225]		Adaption to DECsystem-20 (TOPS-20)
		==================================
		The  following  changes  have  been  made   to   date
		(12-Dec-76):
		The file handling for external  attribute  files  has
		been changed to use GTJFN, OPENF, PMAP, CLOSF instead
		of TOPS-10 UUO's like IN, OPEN,  LOOKUP,  CLOSE.  The
		DEC-10 version is unchanged.
		All three  passes  of  the  compiler  now  reside  in
		(virtual)  core  simultaneously,  i  e  no overlay is
		used.  This means that the SWAPPA (swap  pass)  macro
		is  no longer used. Instead, a direct jump is made to
		the  starting  location  of  the  next  pass  to   be
		executed.
		The one segment version of SIMRTS is used.
		All  executable  files  are  EXE files, not SAV, SHR,
		HGH, LOW.
		At  this stage, it was not possible to convert SIMULA
		to work entirely without monitor UUO's. In  order  to
		provide  a limited possibility of specifying files in
		TOPS-20 fashion, the file specifications may  contain
		a directory name instead of a directory path, thus:
			dev:<directory-name>file.typ
		The   directory   name   is  translated  to  the  ppn
		specification  [4,directory-number],  which  is  then
		used  for  normal  LOOKUP and/or ENTER operations. In
		the case of the external attribute files, the  lookup
		block  is  translated to a file spec string in YFILSP
		(new area in LOWSEG), which is then translated  to  a
		JFN  by  the  GTJFN  JSYS.  No  recognition  input is
		possible, the specification must be complete.
		The attribute files are input by PMAP calls. The high
		end of the compiler is used for a PMAP buffer,  which
		simulates  a  normal  disk  buffer but is longer. The
		current index block is always  placed  in  the  first
		page  of the PMAP buffer, and the following pages are
		used for the modules. O1EXCL unmaps all pages  before
		closing  a file. Command input to the compiler is now
		handled  almost  exclusively  by  Pass  1   routines,
		eliminating  some  duplicated code between the I1 and
		T3 modules. YPASSNO is a global location which  shows
		the  current  pass  number  to prevent loops in error
		processing when the same routine is used in more than
		one pass.
		Changed modules:
		I1.MAC,    O1.MAC,    T3.MAC,   I3.MAC,   LOWSEG.MAC,
		SIMMAC.MAC, T1.MAC, O2SA.MAC.

[226]	(E195)	Compiler pass 3: M3.MAC<M3ATR> - Do not  keep  header
		word  from  old  ATR module - must be zero for SIMULA
		procedure, is non-zero for MACRO-10 or FORTRAN.

[227]	(E196)	LIBSIM:OUTPUT.MAC<PUTREF> (also for PUTSIZ) -
		1) No output if map address = 0.
		2) Output -1 to stand for map in this case.
		3)  Prevent  output  loop  by  moving  loop start for
		prefix chain so a new prototype address is used  each
		time.
		LIBSIM:INPUT.MAC<GETREF>  -  Change  to   allow   for
		changed format of objects (no extraneous output if no
		map).  The format may have to be redesigned later  to
		compress data more.

[230]	(E199)	SIMRTS:IO.MAC  -  Deallocate unwritten Outfile blocks
		if they have not been requested initially by /SIZE:n.
		<.IOCL>:   Check  number  of  blocks (ZOFBLK) against
		ZXBLEN. Deallocate if ZOFBLK > ZXBLEN or ZXBLEN <= 5.
		<.IONB>:   Always  update  ZOFBLK  on  output  for an
		Outfile  to keep track of number of blocks.  This was
		only done if ZOFLIM was set before.

[231]	(E197)	SIMLIB:SANE.MAC (NEW Eventnotice) - Prevent premature
		deallocation  of  a  newly  allocated  ZER  record by
		setting YSADEA(XLOW) = YSATOP(XLOW).  This means that
		an  activation statement executed (indirectly) inside
		a procedure may  destroy  the  stack  nature  of  the
		storage   pool,  if  a  new  ZER  record  has  to  be
		allocated. Each ZER record holds up to 63 notices  in
		the  present  setup.  The  error  gave  a  number  of
		"Illegal memory  reference"     diagnostics  for  big
		Simulation programs.

[232]	(E209)	SIMLIB:RD.MAC<.RDHO>   (Histo(A,B,X,U))   -   Prevent
		writing outside the array A  in  cases  like  A[0:1],
		B[0:0], where X > B[0,0] (the only element).

[233]	(E210)	Compiler  pass  2:CGRK.MAC<CGQU> - Force run time QUA
		check in the case NONE QUA c, c any  class  id.  Will
		give  "OBJECT  NONE"  at run time. CB specifies a run
		time error, not a compile time error. The assumptions
		about  internal  representation  of  "x" in "x QUA c"
		were not valid when x is  a  manifest  NONE,  i  e  a
		constant.

[234]	(E211)	LIBSIM:WRITE.MAC  -  To  prevent  SIMDDT malfunction,
		make SIMDDT believe any error  message  within  WRITE
		was  issued  at  the  point  of  call  to  WRITE, i e
		substitute caller block (ZDRZBI) for XCB, ZDRARE  for
		program address.

[235]	(E212)	LIBSIM:SAVE.MAC<copytobuffer>  - Modified code at end
		of internal buffer when only two words  remain.  Just
		output  one  word  if  only one word is to be copied.
		Some .SAV files had a  superfluous  zero  word  which
		prevented loading.

[236]	(E213)	SIMRTS:IO.MAC<.IOLT>  (Locate) - Add code to test for
		file open (ZFIOPN flag). Error  according  to  CB  if
		file   is   not  open.  Since  ZDFEND  was  reset,  a
		subsequent test on end of file did not find an error,
		and Inimage went wild sometimes.

[237]	(E191)	SIMDDT:SIMDS3.MAC<DSEVTIME>  -  Set  YDSERE only when
		YDSOCOM is on. Prevents  switching  output  from  USE
		file  to  TTY in ALL, VAR or OUTPUT * commands. Error
		message  as  appropriate  on  explicit  reference  to
		x.Evtime, where x is not in SQS.

[240]	(E214)	SIMRTS:PH.MAC<ENTERTHUNK,PROCVALUE>,
		SIMLIB:PHPT.MAC<THUNKENTER,PROCVALUE> -
		Make  left  halves of ZTSRAD and ZTSRSR zero.  GC was
		confused by a left half =  312000  (normal  processor
		flags)  which  it  treated  as  a  block address when
		scanning a display vector (ZDR  record).   The  error
		occurred only in big programs where the data exceeded
		address 312000 (octal).

[241]	(E215)	SIMRTS:OCEP.MAC<OCEX> - Restore  only  AC0-AC14  from
		YUUOAC(XLOW).  SIMDDT  restores  XCB  (AC15) and XIAC
		(AC16)   with    correct    relocation,    if    any.
		YUUOAC+XCB(XLOW)   is   not   relocated.   This  gave
		unpredictable errors before correction.

[242]		SIMDDT changes:
		1)  Allow DISPLAY, USE and @ (indirect file) commands
		even if garbage collection cannot be performed (error
		or  REENTER).  This  is  done  by modifying DSCF.  If
		garbage collection cannot be  performed  (checked  by
		DSCHGC),  DSCF  checks if enough free core remains in
		the pool or can be allocated by a CORE UUO to allow a
		file object with at least one buffer to be allocated.
		The RTS is told NOT to allocate buffers with the file
		in  normal fashion.  Buffers are allocated by the new
		routine DSCFAB and linked by DSCFLB. The  address  of
		the file is marked as special by -1 in the left half.
		Such special files are always closed at PROCEED exit,
		and   the   address   is  cleared  to  allow  garbage
		collection later. USE and "@" files can thus  not  be
		used over SIMDDT exit and entry.

		2)  The  line  number  format  for  DISPLAY  has been
		relaxed. The currently next line can be denoted by  a
		dot  (.), the first line by ^, a large line number by
		*. DISPLAY ^:* thus means display  the  entire  file.
		Colon (:) is used to separate line designations for a
		line interval (- is still valid). The first  line  no
		may be omitted, meaning next line (same as .).
		The notation DISPLAY <line ident>,<number  of  lines>
		is allowed as an alternative way of specifying a line
		interval.  If only the command DISPLAY is given  with
		no  line  numbers,  DISPLAY  .,10 is implied, i e the
		next 10 lines of the current module.
		Also  DISPLAY  <module>:   or  DISPLAY  <module>  are
		allowed forms, meaning  DISPLAY  <module>:.,10  where
		.=0 if this is not the current module.
		Examples: D,5 == DISPLAY .,5
			D:100 == DISPLAY .:100
			D INLINE == DISPLAY INLINE:.,10
			D == DISPLAY .,10

		Affected subroutines: DSGL, DSGLEL(new), DSDP.

		3)  Introduce the switch /START:<octal number> on the
		ALL  and  VARIABLES  commands.  If  the   number   is
		negative,  the  value  of YSATOP(XLOW) is added. Only
		blocks starting at addresses greater than that number
		are dumped.
		Example: ALL/START:35000
		Affected routines: DSVAK, DSIOCT(new), DSVA.

		4) INSPECT/START now repeats the SIMDDT message given
		at an error entry or at REENTER.  This is useful with
		display terminals.
		Affected  routine:    DSPC  (DSPCSP  new  entry  from
		PROCEED,  DSPCSM  called at end of DSPCST sequence to
		repeat msg via new entries DSINRM and DSINEM), DSIN.

		5) Other small changes: Let altmode finish a  command
		line, etc.

		6)  In  .OCSW,  use YACSAV instead of YUUOAC to avoid
		conflicting use (in OCSP<OCRE> and OCEP<OCUU>)

		7) Set TTY channel status to normal if  changed  e.g.
		to  prevent  monitor echoing. SIMDDT commands will be
		echoed.  Channel status is restored at PROCEED.

		8) If Sysout is the terminal and the  buffer  is  not
		empty, force it out followed by crlf to aid debugging
		of certain programs.

[243]	(E229)	SIMLIB: RD.MAC -
		1)    Make    NORMAL    (.RDNO)   return   antithetic
		pseudo-random number for complement of random seed:
		u1:=Inint;  u2:=-u1; x:=Normal(a,b,u1)+Normal(a,b,u2)
		will now yield x=2*a. The distribution is unchanged.
		2)  Split  RD.MAC  into  several  modules  via PRGEND
		pseudo-ops. Common definitions moved to RDINIT  macro
		in SIMRPA.MAC.

		SIMRPA.MAC:   RDINIT  macro  added for Random Drawing
		definitions.

[244]		1) Adjustment of SFD pointer in lookup blocks  -  The
		ppn  field  of a file object or extended lookup block
		may contain an SFD pointer instead  of  a  ppn.  This
		pointer  addresses  the  first  word  of a ZYS block,
		which contains the PATH block. In order  to  use  the
		information  for  lookup,  2  has to be added to that
		pointer.
		- Changes: LIBSIM:RUN.MAC - add 2 to xppn if SFD ptr.

		2)  Make  it possible to override explicit ppn by [-]
		(default   path) -
		OCIN.MAC<GETSPEC> -
		SETOM  OFFSET(ZFDPRG)(XTAC) if [-] specified.
		IONF.MAC<.IOLOK>  -  Change   -1   to   zero   before
		lookup/enter. (-1 works as default path also.)

		3)  IONF.MAC<.IOCF>: Set up extended lookup block for
		all  DSK  files,  including  Infile  and   Printfile.
		Include .RBDEV in block.

		4)  OCIN.MAC<GETSPEC>:  Use DEVPPN to fill in missing
		fields in ppn, e g in LIB:X.MAC[,,A], where ppn  will
		be taken from the LIB device specified via SETSRC.

		5)  IONF.MAC<.IOLOK/.IOENT>  - make sure ppn field is
		reset after LOOKUP/ENTER. Modification of [144].

		6) SIMRPA.MAC - define YDPATH  in  static  area,  not
		used yet.

[245]	(E216)	SIMDDT  <DSAT>  No  breakpoint  on MOVEM XWAC1,d(XCB)
		instruction generated for DO in INSPECT .... WHEN ...
		DO
		The next line is used instead. SIMDDT cannot preserve
		XWAC1  properly,  especially  in  the case of garbage
		collection.

[246]		I1.MAC <I1FN,I1COM>:   Handle  <filespec>!   RUN  the
		program specified.
		T3.MAC <T3>: Let I1COM handle RUN  of  next  CUSP  in
		DEC20   version.   Allow   "RUN  command"  also  from
		terminal.

[247]		SIMMAC.MAC  and  all  modules  invoking  the  MACINIT
		macro:  Include  SEARCH UUOSYM in MACINIT definition,
		thus preparing for a version  of  MACRO  without  UUO
		symbols   predefined.   In  TOPS-20  version,  SEARCH
		MONSYM.

[250]		O1.MAC<O1RL,O1SCOP> Make output of source file lookup
		info to REL file work properly - Output creation time
		and date.

[251]	(E227)	SIMP2:  CGSA.MAC<ZNS.> -  Do  not  use  the  absolute
		address  in  Xtop+1, just keep the dynamic address in
		Xtop, to be made absolute on demand (call to  PUTINT,
		GETINT &c).

[252]	(E228)	SIMRTS:   IO.MAC<.IOOP>  -  Restore  XWAC2,XWAC3 from
		IMG(XWAC1) in case of garbage collection  in  REOPEN.
		XWAC2  was  not  relocated  before TXVA call to blank
		image.

[253]		SIMRTS: OCSP.MAC, SIMRTS.MAC -
		Change  hiseg  names for version 4 (mainly because of
		edit 242):
		SIMR2?.*  changed  to  SIMR4?.*,  SIMRTS  changed  to
		SIMR40.
		SIMDDT.ABS -> SIMDD4.ABS

[254]		SIMRTS:     CS.MAC<.CSSW>   -   Clear   YOBJAD(XLOW),
		YOBJAD+1(XLOW) after use to avoid confusion.

[255]		SIMMAC.MAC:  Introduce EDIT(n) macro, to be  used  in
		edited   modules  for  marking  edits  and  obtaining
		crossreferences of changes.

[256]		Pass 1: I1.MAC<I1FN,I1SC> - If no extension was given
		(no  dot either) assume .SIM for source files.  Empty
		extension (dot only) is marked  by  0,,77777  in  ext
		word of lookup info.

[257]		SIMRTS:      CS.MAC<CSEP>:     Deallocate  also  when
		intermediate results  exist  (acs).  Somewhat  faster
		code.
		<CSEN>:  New entry point .CSENP for entry from  CSSN,
		CSSW.
		<CSSN,CSSW>:  Quicker  display  copy,  BRANCH  .CSENP
		instead
		of .CSEN.

[260]		SIMULA:  I1.MAC, T1.MAC,  I2.MAC,  O2SA.MAC,  I3.MAC,
		T3.MAC,  SIMMAC.MAC  - Make it possible to run SIMULA
		compiler in concealed  mode  (protection  6,  execute
		only).
		Transfer vector introduced in each pass:
		400011 is the normal PORTAL, 400010 is used in Pass 3
		via reenter from other passes  (in  trace  mode).  In
		Pass 1, 400010 is entry point from Pass 3. In Pass 2,
		400010 is equivalent to 400011.
		Note  that  the  modules I1, I2 and I3 must be loaded
		first in each pass!

		SIMRTS: SIMRTS.MAC. Make all JRST instr's in transfer
		vector  PORTAL  instructions.  Also insert PORTAL .+1
		after JSR @YOCGS(XLOW).

[261]		SIMRTS: OCIN.MAC -
		1)  Disallow  calling  SIMDDT  via  ALTMODE  in  file
		dialogue until YDSLOAD(XLOW) has been set  up,  which
		means that the RTS is set up to handle SIMDDT.

		2)  Adjust  stack properly when specification file is
		exhausted (READSPEC).

		3) Do not modify ZSW (RUNSWITCHES)  block  on  lookup
		error (.OCIN).

[262]		SIMULA Pass 1:
		LC.MAC<LC> - Improve line no tests.
		LS.MAC<LS at LSL> - Skip line starting with %

[263]		SIMRTS: OCIO.MAC<GETNAME/GETREST>
		Allow octal spec in file names a la PIP.
		Example: #000013000134.UFD[1,1] specifies an UFD file
		for  [13,134].  SFD's  in  a  path  may  not  be   so
		specified, however.

[264]	(E238)	SIMLIB:PHPT.MAC<PHREFERENCE>  Check for NOTEXT before
		issuing error message.

[265]	(E240)	SIMRTS<.SAGC> Avoid dangerous BLT to save AC's

[266]		SIMRTS:IO.MAC<.IOOP> Linesperpage(-1) for TTY:Sysout

[267]		Modifications to handle PTY: in SIMRTS -
		IO.MAC<.IOCL>.

[270]	(E241)	SIMP2:CGCW.MAC<CGSYC>  -  Clear any ZNO pointer in LH
		of @YTAC  after  incrementing  for  extra  ac  in  IO
		routine  (e g Outtext). Spurious relocation of second
		ac lead to Ill Mem Ref.

[271]	(E242)	SIMRTS:OCEP.MAC<.OCTR> Prevent loop  leading  to  pdl
		overflow.
		SIMP2:  O2.MAC<O2AF> - Fatal error if  no  more  free
		fixups are available.

[272]	(E243)	SIMDDT:SIMDS9.MAC<DSIP>  Allow  :-  for text in INPUT
		command.

[273]		SIMRPA.MAC<STATIC area>, SA.MAC<SAGC PHASE2>:
		Do   not   move   storage   pool   below  address  in
		YSAFRZ(XLOW),  i  e  freeze  core  below  that  point
		(contents  may  be  changed, but no referenced blocks
		are  moved  to  lower  addresses).  This   simplifies
		communication with FORTRAN subroutines.
		*** NOT  yet  implemented  fully  -  leave  for  next
		release ***

[274]		SIMR42:IONF.MAC<REOPEN(.OCINK)>  - Reset YOBJAD(XLOW)
		before exit. Gave error in G C.

[275]	(E244)	SIMULA pass 2: EX.MAC<EXAT> - SUBI 1 => SUBI X3,1  to
		give  correct number of ac's needed for QUICK TEXT or
		LONG REAL procedure.
		Pass 3: E3.MAC:
			E3PPN: Use "OUTINT" (E3PNOU in TOPS-10,
				NOUT in TOPS-20)
			E3PNOU: Save X4 (instead of in E3PVER).

[276]		SIMRTS:SA.MAC<.SAGC,SANP1> -
		Put limit on CORE request at  377777  octal.  TOPS-20
		problem, could be a TOPS-10 problem if very much real
		core is made available to a job.
		Do not output page fault counts - based on  erroneous
		assumptions.

[277]		SIMLIB:OCSP.MAC -
		If program is loaded in high segment with SIMRTS, use
		SETUWP to avoid traps on legitimate stores in  hiseg.
		Do  not  load  hiseg from EXE file then.  SIMHGH.REL,
		containing the RTS modules normally placed in  hiseg,
		is created for this purpose.
		LIBSIM:FREEZE.MAC -
		Load high segment from program file if program loaded
		in hiseg. Affects SAVE.MAC also.

[300]		SIMDDT:
		SIMDS1.MAC - Define %DSVER=:VERRTS for SUTABS.
		SIMDS9.MAC<DSUS> - Linesperpage(-1) for USE file.
		SIMMAC.MAC<RTSYMBOLS>  Introduce  OCLD   for   SIMDDT
		loading.
		SIMRTS.MAC - OCLD added to transfer vector.
		OCEP.MAC<.OCEI> Replace .OCLD by OCLD as value of
		YDSLOAD(XLOW).

5.0	CHANGES ----- RELEASE 3, 18-Dec-75

[40]		CA,CARL,DP,EX,M2,OR,ORRK,P1DUMP,SD,SIMMAC,SR
		Introduce the HIDDEN PROTECTED facility.


[41]		The SIMULA system has been upgraded.
		New features have been added to SIMDDT and it is now
		possible to continue processing after some errors.
		The CLOSE, NOPROCEED and @ commands have been added.
		The NOARRAY command has been removed but it is now
		possible to specify  the switches /-ARRAY, /-TEXT and
		/-GC in all output commands.
		THIS and QUA are accepted in an identification.
		Complete blocks can be output with the * feature.
		^C REENTER will end the processing of the current
		SIMDDT command.
		The VARIABLES command will also give the TYPE PROCEDURE
		values.
		All special characters in a TEXT variable are replaced by
		^ capital letter.
		At end of execution only SYSIN and SYSOUT are closed.
		An error will be generated if some other files are
		open and the user may close them with a SIMDDT command.
		Modules changed: all SIMDDT modules, OCEP and all modules
		which contain a RTS error call for which
		continuation is now possible.

[42]	(E64)	M3 <M3ATR>  Disregard ZHELEN when looking for ATR file
		differences.

[43]	(E63)	Fixup handling changed to avoid forward references.
		Modules O2, O2RK, M3, I2 and LOWSEG changed.

[44]	(E75)	IO module routine .IOBO changed to handle 
		BREAKOUTIMAGE on non TTY device.

[45]	(E50)	Modules O1 and E3 corrected to give some terminating
		errors both on the TTY and the listing.

[46]	(E71)	Module LC corrected to handle a line with 
		a line number and less than 5 characters.

[47]	(E59)	Module CGPA routine .NEW changed to detect generation 
		of object with SIMSET or SIMULATION  via NEW.

[50]	(E80)	CS <CSRA> Work ac's were destroyed by a BLT. Ac's
		reassigned.

[51]	(E70)	SIMDDT routine DSPV changed to give correct start position
		of a subtext  variable.

[52]	(E87)	SIMDDT routine DSBP changed to handle text relations in
		a breakpoint command correctly.

[53]	(E82)	TX module changed to give correct value of GETREAL
		when the text is e.g. 5.E .

[54]	(E86)	TX module changed to give correct value of OUTFIX
		in the interval 0.5 to 1-e.

[55]	(E89)	SIMDDT routine DSRUC corrected to handle a terminated block
		in the operating chain.

[56]	(E99)	CGSA <.RP>  X.A[i], when passed by name, gave error for A a
		REF ARRAY. Corr: Copy ZIDZDE(XP1) to ZNNZQU(XCUR).

[57]		TXBL <TXST>  Strip corrected for the case of a blank subtext
		of length 1-4 starting after first pos of its main text and
		contained in the first word (also blank).

[60]	(E73)	O1 <O1EXRQ>  Do not output more than one request block (type 17)
		for the same REL file library. Missing index ac inserted.

[61]		IO, IONF, OCIO, OCIN, OCEP
		Add bit switch ZFIFND to file object format. When set, errors
		found when handling NEW ...file(...) do not lead to error
		messages, but are flagged to the calling routine instead.
		Makes implementation of utility procedures FINDINFILE,
		FINDDIRECTFILE, SCRATCHFILE etc possible.
		At the same time, tests on several flag bits were partly
		optimized by keeping the flags in an ac as long as possible.

		OCIO <TYPESPEC>  Better output of file definition on errors.

[62]		OCEP <OCEP,OCTR>, SIMRPA 
		%ZYQUFL message introduced. Displays
		the underflow count YOCUFL if non-zero. Increased by one in OCTR
		on each floating point underflow.

[63]		IO, SIMMCR, SIMRTS (SIMRT1, SIMRT2)
		Modifications to enable implementation of binary IO
		(INPUT, OUTPUT). Slight changes in operation and partial
		reorganization of common routines. Adding entries to RTSYMBOLS
		(hiseg transfer vector): IOCB, IOCS, IONB, IORB, IOERF.
		SIMRTS: Save status of channel 0 (if active) over a hiseg swap.

[64]		CGPA <CGPN,CGZAP>  Simplified transmission of array by name.
		Motivated by QUICK procedures.
 		PH <PHFM>  Handling of simple (nothunk) array parameter descr.
		corrected.

[65]	(E101)	CGSA <.DOT,ZID.> In a remote procedure reference like X.p, take
		ZDBZBI from display at level ZHEDLV of qual(X) if qual(X) is
		inspected, otherwise at level ZHBSBL of p. This avoids
		interrupts but may allow "transplantation".
		The corresponding modification is made in ZID. for a connected
		procedure call: INSPECT X DO .... p ...

[66]		TX <TXGI,TXGF,TXGR> Changes to avoid error messages in error
		situations if XTAC left half is non-zero. Used by utility
		procedures scanXXX, checkXXX, where XXX =int/frac/real.

[67]		OCIN <OCINHELP> /H switch at run time handled by SYS:HELPER.REL.
		Channel 0 handled as in OCSW.

[70]	(E97)	TX <TXGR> Corrected deediting of expressions like ".5E".

[71]	(E98)	Module O1 routine O1RLC modified to correct REL file.

[72]	(E78)	Module SA<SAGC> PHASE 4.
		Too much time spent in GC when file opened during processing
		and many records exist.
		Create backward link of records when moving towards top.

[73]	(E102)	CGPA <CGPA.1> Supply correct ZNO pointer in YACTAB for name
		parameter to QUICK procedure. ACS was incorrectly relocated.

[74]	(E103)	PHPT: Check next word in ZAP list on finding zero word. May
		be descriptor for an explicit NONE.

[75]	(E104)	I1 <I1SWFN> YI1RSW turned off to avoid error on concatenation
		of source files. Recovery corrected for error in file spec
		in /R or /S switch.

[76]		IO <.IOFD> XWAC6 also saved.

[77]	(E105)	CP <CPCA,CPRS> Test for detached state simplified. Error in
		CALL procedure (CPCA) corrected (did not work from detached
		caller).

[100]	(E116)	PHPT  Introduce check for too many parameters to NOCHECK
		MACRO-10 procedure. Issue ZYQ106 if too many actual parameters.

[101]		LS <LSXTXT> Implement new handling of text constants.
		They may now be written in several parts, separated by spaces,
		tabs, and new line, thus "<part 1>"<sep>"<part 2>" is equivalent
		to "<part 1><part 2>", where <sep> is space, tab, CR, LF, VT, FF
		or any combination of those.

[102]	(E114)	SIMDDT <DSPB,DSBP,DSAT>
		Breakpoints with relational operators did not work if
		SIMDDT was moved. The relative address of a keyword is now used.

[103]	(E111)	PH <PHTR> Check for inconsistent return from thunk. Give RFAIL
		if block address from thunk save area (ZTSZBI) is zero.
		Operating chain is probably incorrect.

[104]		SIMMAC,SIMMC1-3,SIMMCR,SIMRPA,DM,E3,I3,M3,O3,SIMXRF,T3:
		New definition of CTITLE, RTITLE. CUNIV and RUNIV replace
		them in UNIVERSAL files. This makes it possible to use 
		MACRO v.50 for all but a few MAC files of the SIMULA system.
		In SIMMC3, several macros are lumped together as P3INIT, which
		is invoked in the prologue of every Pass 3 module and in DM.MAC.
		ZDM is removed from ZDM field definitions and instead used as
		explicit offset in field references. MACRO v.50 could not
		handle the earlier definition. The following modules produce a
		loop in v.50: SU,OCIN,I1,LC,SD,CGRK. v.47 has to be used for
		those at present (Feb 1976).
		Note that the universal file name of SIMMC3 is now SIMMC3.UNV!
		Note also that RTITLE does not work, apparently, in v.50 if
		SIMMAC is not searched before other universal files!

[105]		Changes to enable coding of other types of I/O in MACRO-10
		procedures but still use the SIMULA file definition facilities.
		IO <IOFI%D> Do not set data mode if already set. Makes it possible
		to have other modes than ASCII line mode.
		SIMRPA, IONF <.IOCF,.IOCOM>: New bits:
		ZFIBNW (buffers not wanted), ZFINLE (no lookup/enter)
		to suppress buffer allocation and lookup/enter respectively.
		SIMMCR <RTSYMBOLS>: IOCLA available to external MACRO-10
		proc via transfer vector.

[106]	(E110)	O2 <O2DFOUT>
		Check for buffer overflow (IC2 block item 2) corrected.

[107]	(E115)	TX <.TXPX> Outfix corrected for numbers [0.5,1-e]
		with no decimals

[110]	(E90)	RD <.RDRA,.RDUN> RANDINT and UNIFORM corrected. Check for 
		max length of interval

[111]	(E118)	CGPA <.NEW> If class AND its declaring block are both
		visible by inspection, use DLV of declaring block,
		otherwise SBL of class.

[112]	(E75)	IO <.IOBO> Modify [44]: Subtract one from number of line feeds
		either when Breakoutimage was called last or when file is a TTY.
		This gives the (desired?) effect that a series of Break-
		outimage calls will create a long record on a file,
		but Eject will have a reasonable effect.
		<IOCL>: Do not output extra line feed when closing after
		Breakoutimage call.

[113]	(E123)	IOED <IOIT> INTEXT gave pos=length+1 instead of 1.
		This is a mistake in the Common Base document.
		Pos is now consistently 1 for all standard procedures
		yielding text values: (Blanks, Copy, Strip, Sub, Main,
		Intext).

[114]	(E121)	IONF <.IOCF,.IOCOM> When another file is opened on a TTY channel,
	(E122)	the new open destroys the buffer header for the companion file.
		Corrected after allocating the new buffers. In .IOCOM, save
		some effort by checking if there was really an old file on the
		channel.

[115]	(E128)	PH <.PHFT> Allow NOTEXT as actual parameter since t:-NOTEXT
		should be legal by the copy rule for NAME parameters.

[116]	(129)	O2SA <O2SM> Do not output HIDDEN specifications in the
		symbol table.

[117]	(E132)	PHPT: Array parameters to formal, virtual or nocheck MACRO-10
		procedures were treated incorrectly in the simple case when the
		ZAP (actual parameter descriptor) did not specify a thunk.
		Result of edit [64]. Correction in PHVALUE and PHREFERENCE.

5.1	EARLIER CHANGES


PASS 1:

[1]	O1, O1RL
	SD, SDZQU	Output ENTRY block in REL file
			for EXTERNAL CLASS or PROCEDURE
[2]	LOWSEG
	I1, I1REST	Remove use of YVER
[3]	LOWSEG		Introduce YRELBL REL file buffer count
	O1, O1REL	Let 2 REL file buffers stay in core
--------RELEASE 1C(31006)  750220
[4]	SD
	I1
	SIMMC1		Introduce /EXTERN: QUICK and the switch YSWEMQ
			Allow missing ] in PPN
[5]	I1, YI1TMP	Read ^O200 words from TMPCOR
[6]	LC, LCMOVE	Return if XLCLEN=0 after a new source file is opened
[7]	SR, CONSTANTS	Define MAXIDX to ^O12 = 10 = max number of array subsc.
[10]	I1, SIMULA	Introduce PORTAL (GOTO 1, ) to allow concealed mode
[11]	SP		Initialize YC1DC area
[12]	SD, SDBEG
	    SDEXT	Test if EBL less than QMAXDIS and give new error msg.
[13]	O1
	DP
	D1
	I1
	SD
	SP
	SR
	LOWSEG
	SIMMC1		ATR library implementation
			/SEARCH switch added
[14]			New SIMDDT facilities
	SYS1		Macro def of SC moved to SIMMAC
	LC
	LS, Z1CH	Remove <CR> as end of line character
	I1, I1REST	Fill with <LF> in YLCLBE
[15]	LS, LSN		Remove rounding when lreal converted to real
			(to be compatible with RTS)
[16]	O1, O1REL	Modify output of two first buffers
[17]	O1, O1SETB	SAVE X2
[20]	O1, O1EX	Better error messages for errors when reading ATR files
[21]	I1, I1SRTH	Use HELPER.REL for reading SIMCOM.HLP (/H switch)
--------RELEASE 2(0)

PASS 2:

[1]	CGPA, CGNQ	Use ZNNZQU if ZNN node
	CGSA, .DOT	Copy ZNSZQU to ZNNZQU
[2]	O2RK, O2IC2T	Output tentative fixup if present on calling O2DFTE
	O2,O2DFTE	Add the new routine O2DFTE
[3]	OR, NEW.	Loop on ZHBZHB to check parameters in the prefix link
[4]	O2RK, O2REL	See PASS 1 [3]
[5]	ORRK, ORCC
	CGRK, .POW	The check for the POW operator is changed
[6]	CA, BBLK.	Call O2DFTE to output tentative fixup if present
[7]	Introduces QUICK procedures
[10]	CGOB, CGASTX	Check on text procedure id. at text val. assignm.
--------RELEASE 1C(31006)  750220
[11]	CGSA, .FORST	Step ID until XX corrected
[12]	ORRK, ORCCRE	Error in edit [5]  ZCNTYP should be ZCNVAL
[13]	CA, CAEB	Use GENABS to output ZSD pointer when =0
[14]	CGIW, CGG	CAILE instead of CAIL to test if WARNING 1,...
	CGIW, CGIACT
	      CGPD	Make a routine CGIACT of the code in CGPD to initialize
			 YACTAB, YTAC and add initialization of YCGXAC
	CGSA, .ADEC	Call the routine CGIACT to reinitiate YACTAB after
			 EXEC  CSNA is generated
			Reserve ac's in pairs (GETAC2) and do it before COMPVAL
			 is executed to avoid reserving more ac's than needed
	CGSA, CGPU	Use CGIACT
	I2, I2EN	Use CGIACT
[15]	O2SA, O2EX	Initialize LH of YBHATR to buffer length -1
[16]	I2		See PASS1 [10]
[17]	CA, CAEB	Correct fixup no for high seg prototypes
				(IOIN, (IOFI), IOOU, IOPF, IODF )
[20]	CGSA, ZCN.	WARNING 2,REDUNDANT BOOLEAN CONST.  removed
[21]			Not used
[22]			New SIMDDT facilities
	O2SA, O2SM	Set ZSDSPI for SYSIN and SYSOUT
			Copy only ZQUTMK to ZSDTMK
[23]	O2SA, O2ATR	Save X0 too
[24]	CGPA, .PCALL	Generate PUSHJ XPDP,CSSW0 for formal and virtual
			 procedure calls without parameters
[25]	CGRK, .POW	SETZM  YLXIAC   ;Forget old block address
[26]	CGSA, ZCN.	Zero left half if ref constant (NONE)
			Qualification for testing lies in left half
[27]	O2RK, O2REL	See P1[16]
[30]	OR, CVBE. CVDE.	Exec CAUSTD Reserve space for FOR return addresses
	CA, FORDO.	Remove EXEC CAUSTD
[31]	CGPA, CGPN	Test on ZNS-node before test on MODE=NAME
[32]	CGSA, .FORST	Stack X6 with type info.
[33]	CGSA, .FORST	Let zero increment give an infinite loop.
[34]	CGPA, .PCALL	Correct QUICK proc handling. See [7]
[35]	ORRK, ORRPPP	Disallow different types for actual/formal proc
[36]	CARL, CARLVI	Change an instruction to implement correct virtual match
			for REF procedures
--------RELEASE 2(0)

PASS 3:

[1]	T3, T3E		To output T3MERR on list file.
[2]	O3, O3WATR	Copy old ATR file protection.
[3]	T3, NEWNAME	Correct DATE 75 error. Wrong creation date REL file
--------RELEASE 1C(3)  750113
[4]	E3, E3PAGH	DATE 75 error. A ) in list header
[5]	E3, E3PAGH	DATE 75 error. Wrong creation date given in list header
[6]	M3, Main loop	See PASS 1 [3]
	T3, T3I		See PASS 1 [3]
--------RELEASE 1C(31006)  750220
[7]	E3, E3		Start with 0 in YE3PGN
	    E3LICP	Update main page number
	    E3LICS	Do not call E3PAGE but zero YE3PNO to let next line
			 generate new page
			Update main page number by setting secondary 
			 page number to -1
			These changes will correct page number setting
[10]	O3, O3ATR	Call T3A to delete nnnATR.TMP
	T3, T3A		Include T3A to delete nnnATR.TMP
[11]	I3		See PASS 1 [10]
[12]	O3
	SIMDIR		ATR file library.  See PASS 1 [13]
[13]	SIMXRF		Hash on the first 11 bits to sort $,#,@ more correctly
[14]	I3, I3LS3	Zero LOW DATE and TIME in LS3 ENTER block (DATE 75)
[15]			New SIMDDT facilities
	O3, O3TYP	Remove <CR> as end of line character
[16]	M3		Remove some code (See P1[16])
[17]	M3 <M3IQ,M3IQOUT,M3>, SIMMAC, LOWSEG
			Save IQ buffers temporarily
[20]	M3 <M3>, I3 <I3E> Avoid destroying LIBSIM.ATR when creating a new ATR
			file corresponding to a module in LIBSIM.ATR
[21]	O3 <O3ERR>	Save X1 over LD instr
[22]	T3 <T3E>	Check for NEWATR instead of NEWUNR for message
			"NEW ATR FILE GENERATED". Output previous message
			in two parts, the second one only if recompilation
			is necessary (NEWUNR set).

SIMRTS:

[1]	IOED, IOIT	Skip return must be used
[2]	TX, TXFD	Too long loop for numbers less E-38
[3]	OCIN, .OCINB	Enter a blank extension
	IONF, .OCINA	Use WSF instead of SF  to store extension
[4]	TX, TXBD	Do not output leading zeroes if arg in X0 = 0
	TX, TXPX	Output 0 instead of NULLS at end of string
[5]	IO, READBLOCK, CLOSE, OPEN, OUTIMAGE, PUTOUT
			Use global word count ZDFWCT instead of ZBUWCT
			to count words in buffer for directfiles
[6]	TX, .TXDA	Test on NOTEXT and output zeroes in ZTT-record
[7]	TX, TXFD	Neg arg in XWAC3-4 is changed to most pos arg
[10]	IONF, IONFCA	Make a subroutine of the code checking how
			/ACCESS:APPEND is used
[11]	SA, SAGCLE, SAGCN3, SAGCSP
			Debug version test on dispatch table limit
			used QZYS instead of QZXB
[12]	SS, LINKAGE	Add PREV to the symbol table
--------RELEASE 1C(11)  750220
[13]	CS, CSCA	Allow optional AC map as inline parameter
[14]	IO, IOGC	Ignore ^Z if TTY input
[15]	IO, .IOCL	If TTY file zero appropriate half in YIOCHT
			Use X1 to determine CLOSE argument
			CLOSE only in or out side (both for directfile)
			Zero only appropriate side in YIOCHT
			Release TTYn only if no more file on TTYn is open
	    .IOCLA	Let YIOCHT be scanned twice to let two TTY files on
			 the same device be closed and released correctly
			Remove special treatment of SYSOUT
	IONF, .IOCOM	Test device fully first and ask for filename only for
			 directory devices
			Perform the dummy open with a 0 in the 3:rd word of 
			 the argument block
			Put the file object reference in the correct half
			 of YIOCHT for TTY files
			Initiate the buffer header for TTY files
			Perform a RELEASE of new channel if dev. TTYn already
			 assigned
			Check if TTYn already assigned for input or output
			 respectively and give an error
			Treat NUL: as DSK:
[16]	IO, .IOOG	Test on SPACING(0) on TTY-files before <LF> is appended
			Append <LF> before <FF> in non-TTY-files
			Append one <LF> less than ZPFLIN indicates
			 after <FF> in non-TTY-files
[17]			Not used
[20]	OCEP, .OCLD	Set X3 to 1 to let .SAGC be called only once
[21]	OCSP, STOP.	STOP. := FOREX  inserted to take care of STOP statement
			 in FORTRAN subroutines
[22]			New SIMDDT facilities
	SU, SUPS
	    SUSI
	SS, SSLG
	    SSHD
	IO, IOFI
	    IOIN
	    IOOU
	    IOPF
	    IODF	Add second parameter to DZSD calls
[23]	CS, CSSW0	New entry to give an error msg. if parameters missing
[24]	IO		Image always transferred from/to buffer completely
			  (no strip)
[25]	PH, .PHFS	XIAC (X16) saved over .PHFS to avoid addressing problems
[26]	CP, .CPRS	Update YSADEA to YSATOP ( not XCB )
[27]	PH, PHTR
	PHPT, PHPTXT	Zero dynamic ref in thunk save area
[30]	PHPT, PHPTLV	Avoid ABSADDR for label, procedure or switch
[31]	CS, CSCA	Return array address in top ac as given by inline
			parameter  XWD n,address map  if present. Top ac
			is XWAC1+n. Default top ac is XWAC1.
[32]	OCIN, OCINSW	Recognize space and horizontal tab as switch delimiter
[33]	IO, IOIG	Correction for handling of empty image straddling
			buffer end. Also correct EOF image.
[34]	PHPT, PHNAME	Disallow passing type proc by name corresponding to
			a formal procedure of different type.
--------RELEASE 2(0)

SIMDDT:
[1]	SIMDS3, DSPV	Zero LH if ref quantity
		DSVIV		-"-
		DSLV	Use only RH for array addresses
[2]			New SIMDDT facilities
			The DISPLAY and INSPECT commands have been added.
			Some standard procedures may be referenced.
	SIMDS1
	SIMEDS		Add two new error messages
			 QMIPPR=556 Assignm. to syst. proc. not possible
			 QMNINM=557 Text attr. is not MAIN
	SIMEDS		Error msg's 562 and 565 changed
	SIMDS1		MTXMN defined as EXEC TXMN
		DSZSDM	ZSD entry for text.MAIN created
	SIMDS3,	DSNI	Handle text.MAIN
		DSCT	Check for standard procedures
		DSLV		-"-		and call DSSPV
			Handle text.MAIN
		DSSPV	New routine to handle standard procedures
	SIMDS9,	DSIP	Check if input to standard procedures
		DSVA	Check for standard procedures and call DSSPV
	SIMDS1		QZYQLN = 217
	SIMEDS		Old errors ZYQ175-177 converted to ZYQ215-217
			New errors ZYQ044,173-176,214
[2R]	SIMDS1, DSINC1	Test if an address in SIMDDT stack points into OLD
			SIMDDT area.


COMMON PARTS:
[3 10 06]	DM	Never replace the first 10 error messages
			Do not let E messages from pass 1 be replaced by 
			 E messages from later pass
[12 20 11]	SIMMC2
		SIMMAC	Move the constant def of QMAXDIS from SIMMC2 to SIMMAC
[14 22 15]		New SIMDDT facilities
		SIMMAC	Definition of macro SC moved from SYS1
		SIMMCR	Define ZSDHID and ZSDSPI
		SIMRPA	Define ZSDSPI values QIMAIN, QISYSIN,...,QICURRENT
			New definition of macro DZSD, add a second argument
		SIMMAC, LS1INIT
			Move definition of ZLEIND values to LC
		SIMRPA	QFORER=215
			QILLUUO=216
			QRFAIL=217
		SUTEDS.CBL
			RTS-LIMIT  001 thru 217
			T2-CHECK: MOVE 176 to R1
[14 24 15]
RTS[23]		SIMMCR	RTSYMBOLS
			Add the new entry CSSW0 as X(CSSW0) at the end of
			 RTSYMBOLS definition