From 31ddd5ca120494e1ccbd8db04491694ec895ea3a Mon Sep 17 00:00:00 2001
From: ceriel <none@none>
Date: Fri, 19 Feb 1988 15:54:01 +0000
Subject: [PATCH] mainly new comments

---
 lang/m2/libm2/.distr         |  1 -
 lang/m2/libm2/ASCII.def      |  6 ++++++
 lang/m2/libm2/Arguments.c    | 11 ++++++++++
 lang/m2/libm2/Arguments.def  |  6 ++++--
 lang/m2/libm2/ArraySort.mod  |  6 ++++++
 lang/m2/libm2/CSP.def        | 10 +++++----
 lang/m2/libm2/CSP.mod        | 11 ++++++----
 lang/m2/libm2/ChkCards.e     |  9 +++++++++
 lang/m2/libm2/Conversion.def |  5 +++++
 lang/m2/libm2/Conversion.mod | 10 +++++++++
 lang/m2/libm2/EM.def         | 13 +++++++++++-
 lang/m2/libm2/EM.e           |  9 +++++++++
 lang/m2/libm2/Epilogue.def   |  8 +++++++-
 lang/m2/libm2/InOut.def      | 11 ++++++++--
 lang/m2/libm2/InOut.mod      | 13 ++++++++++--
 lang/m2/libm2/LIST           |  2 --
 lang/m2/libm2/LtoUset.e      |  9 +++++++++
 lang/m2/libm2/Makefile       |  2 +-
 lang/m2/libm2/MathLib0.def   |  4 ++++
 lang/m2/libm2/MathLib0.mod   | 10 +++++++++
 lang/m2/libm2/Mathlib.def    |  5 +++++
 lang/m2/libm2/Mathlib.mod    | 10 +++++++++
 lang/m2/libm2/PascalIO.mod   |  5 +++++
 lang/m2/libm2/Processes.def  |  5 +++++
 lang/m2/libm2/Processes.mod  |  7 ++++---
 lang/m2/libm2/RealConver.def |  5 +++++
 lang/m2/libm2/RealConver.mod | 10 +++++++++
 lang/m2/libm2/RealInOut.def  |  5 +++++
 lang/m2/libm2/RealInOut.mod  | 10 +++++++++
 lang/m2/libm2/Semaphores.def | 10 +++++++--
 lang/m2/libm2/Semaphores.mod | 12 +++++++++++
 lang/m2/libm2/Storage.def    |  5 +++++
 lang/m2/libm2/Storage.mod    | 11 ++++++++++
 lang/m2/libm2/StrAss.c       | 16 ++++++++++++---
 lang/m2/libm2/Streams.def    | 18 +++++++++++++----
 lang/m2/libm2/Streams.mod    | 39 ++++++++++++++++++++++++++++++++----
 lang/m2/libm2/Strings.def    |  5 +++++
 lang/m2/libm2/Strings.mod    | 10 +++++++++
 lang/m2/libm2/Terminal.def   |  5 +++++
 lang/m2/libm2/Terminal.mod   | 12 ++++++++++-
 lang/m2/libm2/Traps.def      |  5 +++++
 lang/m2/libm2/Traps.mod      | 11 ++++++++++
 lang/m2/libm2/Unix.def       |  6 +++++-
 lang/m2/libm2/absd.c         | 10 +++++++++
 lang/m2/libm2/absf.e         |  9 +++++++++
 lang/m2/libm2/absi.c         | 11 ++++++++++
 lang/m2/libm2/absl.c         | 10 +++++++++
 lang/m2/libm2/catch.c        | 10 +++++++++
 lang/m2/libm2/confarray.c    | 10 +++++++++
 lang/m2/libm2/halt.c         | 10 +++++++++
 lang/m2/libm2/head_m2.e      | 27 +++++++++----------------
 lang/m2/libm2/load.c         | 10 +++++++++
 lang/m2/libm2/random.def     | 10 +++++++++
 lang/m2/libm2/random.mod     | 19 ++++++++++++++++--
 lang/m2/libm2/rcki.e         |  9 +++++++++
 lang/m2/libm2/rckil.e        |  9 +++++++++
 lang/m2/libm2/rcku.e         |  9 +++++++++
 lang/m2/libm2/rckul.e        |  9 +++++++++
 lang/m2/libm2/stackprio.c    | 10 +++++++++
 lang/m2/libm2/store.c        | 10 +++++++++
 lang/m2/libm2/transfer.e     | 12 +++++++++++
 61 files changed, 529 insertions(+), 58 deletions(-)

diff --git a/lang/m2/libm2/.distr b/lang/m2/libm2/.distr
index dc9fdf46e..d402b31e6 100644
--- a/lang/m2/libm2/.distr
+++ b/lang/m2/libm2/.distr
@@ -15,7 +15,6 @@ RealConver.def
 Semaphores.def
 Storage.def
 Strings.def
-TTY.def
 Terminal.def
 Unix.def
 head_m2.e
diff --git a/lang/m2/libm2/ASCII.def b/lang/m2/libm2/ASCII.def
index 54c0cf474..827b4e0d0 100644
--- a/lang/m2/libm2/ASCII.def
+++ b/lang/m2/libm2/ASCII.def
@@ -1,4 +1,10 @@
+(*$Foreign*)
 DEFINITION MODULE ASCII;
+(*
+  Module:	Mnemonics for ASCII control characters
+  From:		???
+  Version:	$Header$
+*)
 
 CONST
 	nul = 00C;	soh = 01C;	stx = 02C;	etx = 03C;
diff --git a/lang/m2/libm2/Arguments.c b/lang/m2/libm2/Arguments.c
index cbd2c6c24..036dae6d6 100644
--- a/lang/m2/libm2/Arguments.c
+++ b/lang/m2/libm2/Arguments.c
@@ -1,3 +1,14 @@
+/*
+  (c) copyright 1988 by the Vrije Universiteit, Amsterdam, The Netherlands.
+  See the copyright notice in the ACK home directory, in the file "Copyright".
+*/
+
+/*
+  Module:	Access to program arguments and environment
+  Author:	Ceriel J.H. Jacobs
+  Version:	$Header$
+*/
+
 extern char **_argv, **_environ;
 extern int _argc;
 unsigned int Arguments_Argc;
diff --git a/lang/m2/libm2/Arguments.def b/lang/m2/libm2/Arguments.def
index a84950463..c4d19a3f4 100644
--- a/lang/m2/libm2/Arguments.def
+++ b/lang/m2/libm2/Arguments.def
@@ -1,6 +1,8 @@
 DEFINITION MODULE Arguments;
-(*	Routines and variables to access the programs arguments and
-	environment
+(*
+  Module:	Access to program arguments and environment
+  Author:	Ceriel J.H. Jacobs
+  Version:	$Header$
 *)
 
 VAR	Argc: CARDINAL;	(* Number of program arguments, including the program
diff --git a/lang/m2/libm2/ArraySort.mod b/lang/m2/libm2/ArraySort.mod
index 8ad9c3efe..f48162898 100644
--- a/lang/m2/libm2/ArraySort.mod
+++ b/lang/m2/libm2/ArraySort.mod
@@ -1,3 +1,8 @@
+(*
+  (c) copyright 1988 by the Vrije Universiteit, Amsterdam, The Netherlands.
+  See the copyright notice in the ACK home directory, in the file "Copyright".
+*)
+
 (*$R-*)
 IMPLEMENTATION MODULE ArraySort;
 (* 
@@ -21,6 +26,7 @@ IMPLEMENTATION MODULE ArraySort;
   END Sort;
 
   PROCEDURE qsort(a1, a2: ADDRESS; size: CARDINAL);
+  (* Implemented with quick-sort, with some extra's *)
     VAR	left, right, lefteq, righteq: ADDRESS;
 	cmp: CompareResult;
 	mainloop: BOOLEAN;
diff --git a/lang/m2/libm2/CSP.def b/lang/m2/libm2/CSP.def
index 4d0d3193d..5fb7deba0 100644
--- a/lang/m2/libm2/CSP.def
+++ b/lang/m2/libm2/CSP.def
@@ -1,8 +1,10 @@
 DEFINITION MODULE CSP;
-(* From 
-	"A Modula-2 Implementation of CSP",
-	M. Collado, R. Morales, J.J. Moreno,
-	SIGPlan Notices, Volume 22, Number 6, June 1987.
+(*
+  Module:	Communicating Sequential Processes
+  From:		"A Modula-2 Implementation of CSP",
+		M. Collado, R. Morales, J.J. Moreno,
+		SIGPlan Notices, Volume 22, Number 6, June 1987.
+  Version:	$Header$
 
    See this article for an explanation of the use of this module.
 *)
diff --git a/lang/m2/libm2/CSP.mod b/lang/m2/libm2/CSP.mod
index a9c6292c0..74fdd9888 100644
--- a/lang/m2/libm2/CSP.mod
+++ b/lang/m2/libm2/CSP.mod
@@ -1,9 +1,12 @@
 (*$R-*)
 IMPLEMENTATION MODULE CSP;
-(* From 
-	"A Modula-2 Implementation of CSP",
-	M. Collado, R. Morales, J.J. Moreno,
-	SIGPlan Notices, Volume 22, Number 6, June 1987.
+(*
+  Module:	Communicating Sequential Processes
+  From:		"A Modula-2 Implementation of CSP",
+		M. Collado, R. Morales, J.J. Moreno,
+		SIGPlan Notices, Volume 22, Number 6, June 1987.
+		Some modifications by Ceriel J.H. Jacobs
+  Version:	$Header$
 
    See this article for an explanation of the use of this module.
 *)
diff --git a/lang/m2/libm2/ChkCards.e b/lang/m2/libm2/ChkCards.e
index b6d7a0580..036981869 100644
--- a/lang/m2/libm2/ChkCards.e
+++ b/lang/m2/libm2/ChkCards.e
@@ -1,4 +1,13 @@
 #include <m2_traps.h>
+;
+; (c) copyright 1988 by the Vrije Universiteit, Amsterdam, The Netherlands.
+; See the copyright notice in the ACK home directory, in the file "Copyright".
+;
+;
+; Module:	CARDINAL operations with overflow checking
+; Author:	Ceriel J.H. Jacobs
+; Version:	$Header$
+;
 
  mes 2,EM_WSIZE,EM_PSIZE
 
diff --git a/lang/m2/libm2/Conversion.def b/lang/m2/libm2/Conversion.def
index bfaa7e4ad..f732fa284 100644
--- a/lang/m2/libm2/Conversion.def
+++ b/lang/m2/libm2/Conversion.def
@@ -1,4 +1,9 @@
 DEFINITION MODULE Conversions;
+(*
+  Module:	Numeric-to-string conversions
+  Author:	Ceriel J.H. Jacobs
+  Version:	$Header$
+*)
 
   PROCEDURE ConvertOctal(num, len: CARDINAL; VAR str: ARRAY OF CHAR);
   (* Convert number "num" to right-justified octal representation of
diff --git a/lang/m2/libm2/Conversion.mod b/lang/m2/libm2/Conversion.mod
index cdb90c0d7..b64ebc42c 100644
--- a/lang/m2/libm2/Conversion.mod
+++ b/lang/m2/libm2/Conversion.mod
@@ -1,5 +1,15 @@
+(*
+  (c) copyright 1988 by the Vrije Universiteit, Amsterdam, The Netherlands.
+  See the copyright notice in the ACK home directory, in the file "Copyright".
+*)
+
 (*$R-*)
 IMPLEMENTATION MODULE Conversions;
+(*
+  Module:	numeric-to-string conversions
+  Author:	Ceriel J.H. Jacobs
+  Version:	$Header$
+*)
 
   PROCEDURE ConvertNum(num, len, base: CARDINAL;
 		       neg: BOOLEAN;
diff --git a/lang/m2/libm2/EM.def b/lang/m2/libm2/EM.def
index 755d6b4a4..82b53de10 100644
--- a/lang/m2/libm2/EM.def
+++ b/lang/m2/libm2/EM.def
@@ -1,6 +1,10 @@
 (*$Foreign *)
 DEFINITION MODULE EM;
-(* An interface to EM instructions and data *)
+(*
+  Module:	Interface to some EM instructions and data
+  Author:	Ceriel J.H. Jacobs
+  Version:	$Header$
+*)
 
 	FROM SYSTEM IMPORT ADDRESS;
 
@@ -20,8 +24,15 @@ DEFINITION MODULE EM;
 	(* Generate EM trap number "trapno" *)
 
 	PROCEDURE SIG(t: TrapHandler): TrapHandler;
+	(* install traphandler t; return previous handler *)
 
 	PROCEDURE FILN(): ADDRESS;
+	(* return current program file-name. This only works if file-name
+	   and line-number generation is not disabled during compilation
+	*)
 
 	PROCEDURE LINO(): INTEGER;
+	(* return current program line-number. This only works if file-name
+	   and line-number generation is not disabled during compilation
+	*)
 END EM.
diff --git a/lang/m2/libm2/EM.e b/lang/m2/libm2/EM.e
index 174c82fc8..f5f1b3655 100644
--- a/lang/m2/libm2/EM.e
+++ b/lang/m2/libm2/EM.e
@@ -1,4 +1,13 @@
 #
+;
+; (c) copyright 1988 by the Vrije Universiteit, Amsterdam, The Netherlands.
+; See the copyright notice in the ACK home directory, in the file "Copyright".
+;
+;
+; Module:	Interface to some EM instructions and data
+; Author:	Ceriel J.H. Jacobs
+; Version:	$Header$
+;
  mes 2,EM_WSIZE,EM_PSIZE
 
 #define ARG1    0
diff --git a/lang/m2/libm2/Epilogue.def b/lang/m2/libm2/Epilogue.def
index ea6d6e9d9..ee87c4640 100644
--- a/lang/m2/libm2/Epilogue.def
+++ b/lang/m2/libm2/Epilogue.def
@@ -1,6 +1,12 @@
 (*$Foreign*)
 DEFINITION MODULE Epilogue;
-(* MODULA-2 offers a facility for the initialization of modules, but there
+(*
+  Module:	install module termination procedures to be called at
+		program termination
+  Author:	Ceriel J.H. Jacobs
+  Version:	$Header$
+
+   MODULA-2 offers a facility for the initialization of modules, but there
    is no mechanism to have some code executed when the program finishes.
    This module is a feeble attempt at solving this problem.
 *)
diff --git a/lang/m2/libm2/InOut.def b/lang/m2/libm2/InOut.def
index 1179298be..d8c142c47 100644
--- a/lang/m2/libm2/InOut.def
+++ b/lang/m2/libm2/InOut.def
@@ -1,4 +1,9 @@
 DEFINITION MODULE InOut;
+(*
+  Module:	Wirth's Input/Output module
+  From:		"Programming in Modula-2", 3rd, corrected edition, by N. Wirth
+  Version:	$Header$
+*)
 
 	CONST	EOL = 12C;
 
@@ -23,11 +28,13 @@ DEFINITION MODULE InOut;
 	*)
 
 	PROCEDURE OpenInputFile(filename: ARRAY OF CHAR);
-	(* Like OpenInput, but filename given as parameter
+	(* Like OpenInput, but filename given as parameter.
+	   This procedure is not in Wirth's InOut.
 	*)
 
 	PROCEDURE OpenOutputFile(filename: ARRAY OF CHAR);
-	(* Like OpenOutput, but filename given as parameter
+	(* Like OpenOutput, but filename given as parameter.
+	   This procedure is not in Wirth's InOut.
 	*)
 
 	PROCEDURE CloseInput;
diff --git a/lang/m2/libm2/InOut.mod b/lang/m2/libm2/InOut.mod
index ab7eebfe2..2fd077171 100644
--- a/lang/m2/libm2/InOut.mod
+++ b/lang/m2/libm2/InOut.mod
@@ -1,10 +1,19 @@
+(*
+  (c) copyright 1988 by the Vrije Universiteit, Amsterdam, The Netherlands.
+  See the copyright notice in the ACK home directory, in the file "Copyright".
+*)
+
 (*$R-*)
 IMPLEMENTATION MODULE InOut ;
+(*
+  Module:	Wirth's Input/Output module
+  Author:	Ceriel J.H. Jacobs
+  Version:	$Header$
+*)
 
   IMPORT Streams;
   IMPORT Conversions;
   IMPORT Traps;
-  FROM TTY IMPORT isatty;
 
   CONST	TAB = 11C;
 
@@ -123,7 +132,7 @@ IMPLEMENTATION MODULE InOut ;
 	j : CARDINAL;
   BEGIN
 	Done := TRUE;
-	IF isatty(0) THEN
+	IF isatty(Streams.InputStream) THEN
 		XWriteString(prompt);
 	END;
 	XReadString(buf);
diff --git a/lang/m2/libm2/LIST b/lang/m2/libm2/LIST
index 3c5b0b20f..91e78c4a7 100644
--- a/lang/m2/libm2/LIST
+++ b/lang/m2/libm2/LIST
@@ -5,8 +5,6 @@ RealInOut.mod
 InOut.mod
 Streams.mod
 Terminal.mod
-TTY.mod
-ASCII.mod
 MathLib0.mod
 Mathlib.mod
 Processes.mod
diff --git a/lang/m2/libm2/LtoUset.e b/lang/m2/libm2/LtoUset.e
index 595747240..2be4da7d6 100644
--- a/lang/m2/libm2/LtoUset.e
+++ b/lang/m2/libm2/LtoUset.e
@@ -1,4 +1,13 @@
 #
+;
+; (c) copyright 1988 by the Vrije Universiteit, Amsterdam, The Netherlands.
+; See the copyright notice in the ACK home directory, in the file "Copyright".
+;
+;
+; Module:	Compute non-constant set displays
+; Author:	Ceriel J.H. Jacobs
+; Version:	$Header$
+;
  mes 2,EM_WSIZE,EM_PSIZE
 
  ; _LtoUset is called for set displays containing { expr1 .. expr2 }.
diff --git a/lang/m2/libm2/Makefile b/lang/m2/libm2/Makefile
index b945a1861..313d130f5 100644
--- a/lang/m2/libm2/Makefile
+++ b/lang/m2/libm2/Makefile
@@ -4,7 +4,7 @@ DEFDIR = $(HOME)/lib/m2
 SOURCES =	ASCII.def EM.def MathLib0.def Processes.def \
 		RealInOut.def Storage.def Arguments.def Conversion.def \
 		random.def Semaphores.def Unix.def RealConver.def \
-		Strings.def InOut.def Terminal.def TTY.def \
+		Strings.def InOut.def Terminal.def \
 		Mathlib.def PascalIO.def Traps.def CSP.def \
 		Epilogue.def Streams.def ArraySort.def
 
diff --git a/lang/m2/libm2/MathLib0.def b/lang/m2/libm2/MathLib0.def
index 985a6da44..196c66e82 100644
--- a/lang/m2/libm2/MathLib0.def
+++ b/lang/m2/libm2/MathLib0.def
@@ -1,5 +1,9 @@
 DEFINITION MODULE MathLib0;
 (*
+  Module:	Some mathematical functions
+  From:		"Programming in Modula-2", 3rd, corrected edition, by N. Wirth
+  Version:	$Header$
+
 	Exists for compatibility.
 	A more elaborate math lib can be found in Mathlib.def
 *)
diff --git a/lang/m2/libm2/MathLib0.mod b/lang/m2/libm2/MathLib0.mod
index 9834ac036..a27d29ffa 100644
--- a/lang/m2/libm2/MathLib0.mod
+++ b/lang/m2/libm2/MathLib0.mod
@@ -1,5 +1,15 @@
+(*
+  (c) copyright 1988 by the Vrije Universiteit, Amsterdam, The Netherlands.
+  See the copyright notice in the ACK home directory, in the file "Copyright".
+*)
+
 (*$R-*)
 IMPLEMENTATION MODULE MathLib0;
+(*
+  Module:	Some mathematical functions
+  Author:	Ceriel J.H. Jacobs
+  Version:	$Header$
+*)
 
   IMPORT Mathlib;
 
diff --git a/lang/m2/libm2/Mathlib.def b/lang/m2/libm2/Mathlib.def
index 979d1b696..d860673f3 100644
--- a/lang/m2/libm2/Mathlib.def
+++ b/lang/m2/libm2/Mathlib.def
@@ -1,4 +1,9 @@
 DEFINITION MODULE Mathlib;
+(*
+  Module:	Mathematical functions
+  Author:	Ceriel J.H. Jacobs
+  Version:	$Header$
+*)
 
   (* Some mathematical constants: *)
 
diff --git a/lang/m2/libm2/Mathlib.mod b/lang/m2/libm2/Mathlib.mod
index 79858a34f..7b84f89d6 100644
--- a/lang/m2/libm2/Mathlib.mod
+++ b/lang/m2/libm2/Mathlib.mod
@@ -1,5 +1,15 @@
+(*
+  (c) copyright 1988 by the Vrije Universiteit, Amsterdam, The Netherlands.
+  See the copyright notice in the ACK home directory, in the file "Copyright".
+*)
+
 (*$R-*)
 IMPLEMENTATION MODULE Mathlib;
+(*
+  Module:	Mathematical functions
+  Author:	Ceriel J.H. Jacobs
+  Version:	$Header$
+*)
 
   FROM EM IMPORT FIF, FEF;
   FROM Traps IMPORT Message;
diff --git a/lang/m2/libm2/PascalIO.mod b/lang/m2/libm2/PascalIO.mod
index ecfdd7ebc..352a77d65 100644
--- a/lang/m2/libm2/PascalIO.mod
+++ b/lang/m2/libm2/PascalIO.mod
@@ -1,3 +1,8 @@
+(*
+  (c) copyright 1988 by the Vrije Universiteit, Amsterdam, The Netherlands.
+  See the copyright notice in the ACK home directory, in the file "Copyright".
+*)
+
 (*$R-*)
 IMPLEMENTATION MODULE PascalIO;
 (*
diff --git a/lang/m2/libm2/Processes.def b/lang/m2/libm2/Processes.def
index 8437deba3..0bbac30be 100644
--- a/lang/m2/libm2/Processes.def
+++ b/lang/m2/libm2/Processes.def
@@ -1,4 +1,9 @@
 DEFINITION MODULE Processes;
+(*
+  Module:	Processes
+  From:		"Programming in Modula-2", 3rd, corrected edition, by N. Wirth
+  Version:	$Header$
+*)
 
 	TYPE SIGNAL;
 
diff --git a/lang/m2/libm2/Processes.mod b/lang/m2/libm2/Processes.mod
index 2bc5d66d8..18b28a6b2 100644
--- a/lang/m2/libm2/Processes.mod
+++ b/lang/m2/libm2/Processes.mod
@@ -1,8 +1,9 @@
 (*$R-*)
 IMPLEMENTATION MODULE Processes [1];
-(* This implementation module comes from
-	"Programming in Modula-2", by Niklaus Wirth,
-	3rd edition, Springer-Verlag, New York, 1985
+(*
+  Module:       Processes
+  From:         "Programming in Modula-2", 3rd, corrected edition, by N. Wirth
+  Version:      $Header$
 *)
 
   FROM SYSTEM IMPORT ADDRESS, TSIZE, NEWPROCESS, TRANSFER;
diff --git a/lang/m2/libm2/RealConver.def b/lang/m2/libm2/RealConver.def
index 680856495..e97083627 100644
--- a/lang/m2/libm2/RealConver.def
+++ b/lang/m2/libm2/RealConver.def
@@ -1,4 +1,9 @@
 DEFINITION MODULE RealConversions;
+(*
+  Module:	string-to-real and real-to-string conversions
+  Author:	Ceriel J.H. Jacobs
+  Version:	$Header$
+*)
 
   PROCEDURE StringToReal(str: ARRAY OF CHAR; VAR r: REAL; VAR ok: BOOLEAN);
   (* Convert string "str" to a real number "r" according to the syntax:
diff --git a/lang/m2/libm2/RealConver.mod b/lang/m2/libm2/RealConver.mod
index bcd21094d..eac853e7b 100644
--- a/lang/m2/libm2/RealConver.mod
+++ b/lang/m2/libm2/RealConver.mod
@@ -1,5 +1,15 @@
+(*
+  (c) copyright 1988 by the Vrije Universiteit, Amsterdam, The Netherlands.
+  See the copyright notice in the ACK home directory, in the file "Copyright".
+*)
+
 (*$R-*)
 IMPLEMENTATION MODULE RealConversions;
+(*
+  Module:       string-to-real and real-to-string conversions
+  Author:       Ceriel J.H. Jacobs
+  Version:      $Header$
+*)
 
   FROM EM IMPORT FIF;
 
diff --git a/lang/m2/libm2/RealInOut.def b/lang/m2/libm2/RealInOut.def
index c7eb7eb1a..6a13a4839 100644
--- a/lang/m2/libm2/RealInOut.def
+++ b/lang/m2/libm2/RealInOut.def
@@ -1,4 +1,9 @@
 DEFINITION MODULE RealInOut;
+(*
+  Module:	InOut for REAL numbers
+  From:		"Programming in Modula-2", 3rd, corrected edition, by N. Wirth
+  Version:	$Header$
+*)
 
   VAR Done: BOOLEAN;
 
diff --git a/lang/m2/libm2/RealInOut.mod b/lang/m2/libm2/RealInOut.mod
index 64a97d246..342180141 100644
--- a/lang/m2/libm2/RealInOut.mod
+++ b/lang/m2/libm2/RealInOut.mod
@@ -1,5 +1,15 @@
+(*
+  (c) copyright 1988 by the Vrije Universiteit, Amsterdam, The Netherlands.
+  See the copyright notice in the ACK home directory, in the file "Copyright".
+*)
+
 (*$R-*)
 IMPLEMENTATION MODULE RealInOut;
+(*
+  Module:       InOut for REAL numbers
+  Author:	Ceriel J.H. Jacobs
+  Version:      $Header$
+*)
 
   IMPORT InOut;
   IMPORT RealConversions;
diff --git a/lang/m2/libm2/Semaphores.def b/lang/m2/libm2/Semaphores.def
index 9883fb971..53a674e73 100644
--- a/lang/m2/libm2/Semaphores.def
+++ b/lang/m2/libm2/Semaphores.def
@@ -1,4 +1,12 @@
 DEFINITION MODULE Semaphores;
+(*
+  Module:	Processes with semaphores
+  Author:	Ceriel J.H. Jacobs
+  Version:	$Header$
+
+  On systems using quasi-concurrency, the only opportunities for process-
+  switches are calls to Down and Up.
+*)
 
   TYPE Sema;
 
@@ -12,12 +20,10 @@ DEFINITION MODULE Semaphores;
   (* If the value of "s" is > 0, then just decrement "s".
      Else, suspend the current process until the semaphore becomes
      positive again.
-     May result in a process switch.
   *)
 
   PROCEDURE Up(VAR s: Sema);
   (* Increment the semaphore "s".
-     This call may result in a process switch
   *)
 
   PROCEDURE StartProcess(P: PROC; n: CARDINAL);
diff --git a/lang/m2/libm2/Semaphores.mod b/lang/m2/libm2/Semaphores.mod
index 96fc2482b..776722560 100644
--- a/lang/m2/libm2/Semaphores.mod
+++ b/lang/m2/libm2/Semaphores.mod
@@ -1,5 +1,17 @@
+(*
+  (c) copyright 1988 by the Vrije Universiteit, Amsterdam, The Netherlands.
+  See the copyright notice in the ACK home directory, in the file "Copyright".
+*)
+
 (*$R-*)
 IMPLEMENTATION MODULE Semaphores [1];
+(*
+  Module:       Processes with semaphores
+  Author:       Ceriel J.H. Jacobs
+  Version:      $Header$
+
+  Quasi-concurrency implementation
+*)
 
   FROM SYSTEM IMPORT ADDRESS, NEWPROCESS, TRANSFER;
   FROM Storage IMPORT ALLOCATE;
diff --git a/lang/m2/libm2/Storage.def b/lang/m2/libm2/Storage.def
index fda4c9c48..234562b4d 100644
--- a/lang/m2/libm2/Storage.def
+++ b/lang/m2/libm2/Storage.def
@@ -1,4 +1,9 @@
 DEFINITION MODULE Storage;
+(*
+  Module:	Dynamic storage allocation
+  From:		"Programming in Modula-2", 3rd, corrected edition, by N. Wirth
+  Version:	$Header$
+*)
 
 	FROM SYSTEM IMPORT ADDRESS;
 
diff --git a/lang/m2/libm2/Storage.mod b/lang/m2/libm2/Storage.mod
index e3e30faa2..19a7d3b0a 100644
--- a/lang/m2/libm2/Storage.mod
+++ b/lang/m2/libm2/Storage.mod
@@ -1,5 +1,16 @@
+(*
+  (c) copyright 1988 by the Vrije Universiteit, Amsterdam, The Netherlands.
+  See the copyright notice in the ACK home directory, in the file "Copyright".
+*)
+
 (*$R-*)
 IMPLEMENTATION MODULE Storage;
+(*
+  Module:	Dynamic Storage Allocation
+  Author:	Ceriel J.H. Jacobs
+		Adapted from a version in C by Hans Tebra
+  Version:	$Header$
+*)
 (* This storage manager maintains an array of lists of objects with the
    same size. Commonly used sizes have their own bucket. The larger ones
    are put in a single list.
diff --git a/lang/m2/libm2/StrAss.c b/lang/m2/libm2/StrAss.c
index 371042d0a..92f100119 100644
--- a/lang/m2/libm2/StrAss.c
+++ b/lang/m2/libm2/StrAss.c
@@ -1,3 +1,14 @@
+/*
+  (c) copyright 1988 by the Vrije Universiteit, Amsterdam, The Netherlands.
+  See the copyright notice in the ACK home directory, in the file "Copyright".
+*/
+
+/*
+  Module:	assign string to character array, with possible 0-byte
+		extension
+  Author:	Ceriel J.H. Jacobs
+  Version:	$Header$
+*/
 _StringAssign(dstsiz, srcsiz, dstaddr, srcaddr)
 	register char *dstaddr, *srcaddr;
 {
@@ -6,8 +17,7 @@ _StringAssign(dstsiz, srcsiz, dstaddr, srcaddr)
 		srcsiz--;
 		dstsiz--;
 	}
-	while (dstsiz > 0) {
-		*dstaddr++ = 0;
-		dstsiz--;
+	if (dstsiz > 0) {
+		*dstaddr = 0;
 	}
 }
diff --git a/lang/m2/libm2/Streams.def b/lang/m2/libm2/Streams.def
index 4bdc85168..e61336723 100644
--- a/lang/m2/libm2/Streams.def
+++ b/lang/m2/libm2/Streams.def
@@ -1,5 +1,9 @@
 DEFINITION MODULE Streams;
 (*
+  Module:	Stream Input/Output
+  Author:	Ceriel J.H. Jacobs
+  Version:	$Header$
+
  * This module provides sequential IO through streams.
  * A stream is either a text stream or a binary stream, and is either in
  * reading, writing or appending mode.
@@ -134,10 +138,16 @@ DEFINITION MODULE Streams;
 			position: LONGINT;
 			VAR result: StreamResult);
   (* sets the actual read/write position to "position".
-     "result" is set to illegaloperation if "stream" is not a stream or
-     the stream was opened for appending and the position is in front of
-     the current position, or it failed for some other
-     reason (f.i. when the stream is connected to a terminal).
+     "result" is set to nostream if "stream" is not a stream.
+     It is set to illegaloperation if the stream was opened for appending and
+     the position is in front of the current position, or it failed for some
+     other reason (f.i. when the stream is connected to a terminal).
+  *)
+
+  PROCEDURE isatty(stream: Stream; VAR result: StreamResult): BOOLEAN;
+  (* return TRUE if the stream is connected to a terminal.
+     "result" is set to nostream if "stream" is not a stream, and
+     set to illegaloperation if the operation failed for some other reason.
   *)
 
 END Streams.
diff --git a/lang/m2/libm2/Streams.mod b/lang/m2/libm2/Streams.mod
index 23f472ecd..dd4f918e2 100644
--- a/lang/m2/libm2/Streams.mod
+++ b/lang/m2/libm2/Streams.mod
@@ -1,8 +1,21 @@
+#
+(*
+  (c) copyright 1988 by the Vrije Universiteit, Amsterdam, The Netherlands.
+  See the copyright notice in the ACK home directory, in the file "Copyright".
+*)
+
 (*$R-*)
 IMPLEMENTATION MODULE Streams;
+(*
+  Module:       Stream Input/Output
+  Author:       Ceriel J.H. Jacobs
+  Version:      $Header$
+
+  Implementation for Unix
+*)
 
   FROM SYSTEM IMPORT BYTE, ADR;
-  IMPORT Unix, TTY, Storage, Epilogue;
+  IMPORT Unix, Storage, Epilogue;
 
   CONST BUFSIZ = 1024;	(* tunable *)
   TYPE	IOB = RECORD
@@ -332,7 +345,7 @@ IMPLEMENTATION MODULE Streams;
   BEGIN
 	currpos := 0D;
 	IF (s = NIL) OR (s^.kind = none) THEN
-		result := illegaloperation;
+		result := nostream;
 		RETURN;
 	END;
 	IF (s^.mode # reading) THEN
@@ -360,6 +373,24 @@ IMPLEMENTATION MODULE Streams;
 	result := succeeded;
   END SetPosition;
 
+  PROCEDURE isatty(stream: Stream): BOOLEAN;
+    VAR buf: ARRAY[1..100] OF CHAR;
+  BEGIN
+	IF (stream = NIL) OR (s^.kind = none) THEN
+		result := nostream;
+		RETURN FALSE;
+	END;
+#ifdef __USG
+	RETURN ioctl(stream^.fildes, INTEGER(ORD('T') * 256 + 1), ADR(buf)) >= 0;
+#else
+#ifdef __BSD4_2
+	RETURN ioctl(stream^.fildes, INTEGER(ORD('t') * 256 + 8 + 6*65536 + 40000000H), ADR(buf)) >= 0;
+#else
+	RETURN ioctl(stream^.fildes, INTEGER(ORD('t') * 256 + 8), ADR(buf)) >= 0;
+#endif
+#endif
+  END isatty;
+
 BEGIN
 	InputStream := ADR(ibuf);
 	OutputStream := ADR(obuf);
@@ -383,7 +414,7 @@ BEGIN
 		maxcnt := 0;
 		cnt := 0;
 		bufferedcnt := BUFSIZ;
-		IF TTY.isatty(1) THEN
+		IF isatty(OutputStream) THEN
 			buffering := linebuffered;
 		ELSE
 			buffering := blockbuffered;
@@ -398,7 +429,7 @@ BEGIN
 		maxcnt := 0;
 		cnt := 0;
 		bufferedcnt := BUFSIZ;
-		IF TTY.isatty(2) THEN
+		IF isatty(ErrorStream) THEN
 			buffering := linebuffered;
 		ELSE
 			buffering := blockbuffered;
diff --git a/lang/m2/libm2/Strings.def b/lang/m2/libm2/Strings.def
index a5ce67eae..d2f22d558 100644
--- a/lang/m2/libm2/Strings.def
+++ b/lang/m2/libm2/Strings.def
@@ -1,4 +1,9 @@
 DEFINITION MODULE Strings;
+(*
+  Module:	String manipulations
+  Author:	Ceriel J.H. Jacobs
+  Version:	$Header$
+*)
 (* Note: truncation of strings may occur if the user does not provide
    large enough variables to contain the result of the operation.
 *)
diff --git a/lang/m2/libm2/Strings.mod b/lang/m2/libm2/Strings.mod
index 9d1226132..20e6ccce9 100644
--- a/lang/m2/libm2/Strings.mod
+++ b/lang/m2/libm2/Strings.mod
@@ -1,5 +1,15 @@
+(*
+  (c) copyright 1988 by the Vrije Universiteit, Amsterdam, The Netherlands.
+  See the copyright notice in the ACK home directory, in the file "Copyright".
+*)
+
 (*$R-*)
 IMPLEMENTATION MODULE Strings;
+(*
+  Module:       String manipulations
+  Author:       Ceriel J.H. Jacobs
+  Version:      $Header$
+*)
 
 PROCEDURE Assign(source: ARRAY OF CHAR; VAR dest: ARRAY OF CHAR);
 (* Assign string source to dest
diff --git a/lang/m2/libm2/Terminal.def b/lang/m2/libm2/Terminal.def
index 1a5a71a52..7ea3e63c1 100644
--- a/lang/m2/libm2/Terminal.def
+++ b/lang/m2/libm2/Terminal.def
@@ -1,4 +1,9 @@
 DEFINITION MODULE Terminal;
+(*
+  Module:	Input/Output to/from terminals
+  From:		"Programming in Modula-2", 3rd, corrected edition, by N. Wirth
+  Version:	$Header$
+*)
 
 	PROCEDURE Read(VAR ch : CHAR);
 	(* Read a character from the terminal and leave it in ch
diff --git a/lang/m2/libm2/Terminal.mod b/lang/m2/libm2/Terminal.mod
index 2c905a2a1..0ac6c61c3 100644
--- a/lang/m2/libm2/Terminal.mod
+++ b/lang/m2/libm2/Terminal.mod
@@ -1,7 +1,17 @@
 #
+(*
+  (c) copyright 1988 by the Vrije Universiteit, Amsterdam, The Netherlands.
+  See the copyright notice in the ACK home directory, in the file "Copyright".
+*)
+
 (*$R-*)
 IMPLEMENTATION MODULE Terminal;
-(* This implementation is Unix-dependant
+(*
+  Module:       Input/Output to/from terminals
+  Author:	Ceriel J.H. Jacobs
+  Version:      $Header$
+
+  Implementation for Unix.
 *)
   IMPORT Unix;
   FROM SYSTEM IMPORT ADR;
diff --git a/lang/m2/libm2/Traps.def b/lang/m2/libm2/Traps.def
index 46d34aa1b..fc6d17421 100644
--- a/lang/m2/libm2/Traps.def
+++ b/lang/m2/libm2/Traps.def
@@ -1,4 +1,9 @@
 DEFINITION MODULE Traps;
+(*
+  Module:	Facility for handling traps
+  Author:	Ceriel J.H. Jacobs
+  Version:	$Header$
+*)
 
   IMPORT EM;
 
diff --git a/lang/m2/libm2/Traps.mod b/lang/m2/libm2/Traps.mod
index 2e8f9ff25..e8874b737 100644
--- a/lang/m2/libm2/Traps.mod
+++ b/lang/m2/libm2/Traps.mod
@@ -1,5 +1,16 @@
+(*
+  (c) copyright 1988 by the Vrije Universiteit, Amsterdam, The Netherlands.
+  See the copyright notice in the ACK home directory, in the file "Copyright".
+*)
+
 (*$R-*)
 IMPLEMENTATION MODULE Traps;
+(*
+  Module:       Facility for handling traps
+  Author:       Ceriel J.H. Jacobs
+  Version:      $Header$
+*)
+
   IMPORT EM;
   IMPORT Unix;
   FROM SYSTEM IMPORT ADDRESS, ADR;
diff --git a/lang/m2/libm2/Unix.def b/lang/m2/libm2/Unix.def
index afa212328..57e238e99 100644
--- a/lang/m2/libm2/Unix.def
+++ b/lang/m2/libm2/Unix.def
@@ -1,6 +1,10 @@
 (*$Foreign language module *)
 DEFINITION MODULE Unix;
-(*	An interface to some Unix system-calls *)
+(*
+  Module:	interface to some Unix systemcalls
+  Author:	Ceriel J.H. Jacobs
+  Version:	$Header$
+*)
   FROM SYSTEM IMPORT WORD, ADDRESS;
 
 (* Type needed for Signal *)
diff --git a/lang/m2/libm2/absd.c b/lang/m2/libm2/absd.c
index f0d5c5334..51ce0b5d4 100644
--- a/lang/m2/libm2/absd.c
+++ b/lang/m2/libm2/absd.c
@@ -1,3 +1,13 @@
+/*
+  (c) copyright 1988 by the Vrije Universiteit, Amsterdam, The Netherlands.
+  See the copyright notice in the ACK home directory, in the file "Copyright".
+*/
+
+/*
+  Module:	double abs function
+  Author:	Ceriel J.H. Jacobs
+  Version:	$Header$
+*/
 #ifndef NOFLOAT
 double
 _absd(i)
diff --git a/lang/m2/libm2/absf.e b/lang/m2/libm2/absf.e
index f52bcbe59..ff9f4d9ec 100644
--- a/lang/m2/libm2/absf.e
+++ b/lang/m2/libm2/absf.e
@@ -1,4 +1,13 @@
 #
+;
+; (c) copyright 1988 by the Vrije Universiteit, Amsterdam, The Netherlands.
+; See the copyright notice in the ACK home directory, in the file "Copyright".
+;
+;
+; Module:	REAL abs function
+; Author:	Ceriel J.H. Jacobs
+; Version:	$Header$
+;
  mes 2,EM_WSIZE,EM_PSIZE
  exp $_absf
  pro $_absf,0
diff --git a/lang/m2/libm2/absi.c b/lang/m2/libm2/absi.c
index 16c883849..438179203 100644
--- a/lang/m2/libm2/absi.c
+++ b/lang/m2/libm2/absi.c
@@ -1,3 +1,14 @@
+/*
+  (c) copyright 1988 by the Vrije Universiteit, Amsterdam, The Netherlands.
+  See the copyright notice in the ACK home directory, in the file "Copyright".
+*/
+
+/*
+  Module:	integer abs function
+  Author:	Ceriel J.H. Jacobs
+  Version:	$Header$
+*/
+
 _absi(i)
 {
 	return i >= 0 ? i : -i;
diff --git a/lang/m2/libm2/absl.c b/lang/m2/libm2/absl.c
index 20feb980d..ae8aa4c34 100644
--- a/lang/m2/libm2/absl.c
+++ b/lang/m2/libm2/absl.c
@@ -1,3 +1,13 @@
+/*
+  (c) copyright 1988 by the Vrije Universiteit, Amsterdam, The Netherlands.
+  See the copyright notice in the ACK home directory, in the file "Copyright".
+*/
+
+/*
+  Module:	longint abs function
+  Author:	Ceriel J.H. Jacobs
+  Version:	$Header$
+*/
 long
 _absl(i)
 	long i;
diff --git a/lang/m2/libm2/catch.c b/lang/m2/libm2/catch.c
index 2e6a4ae6d..ca6402c35 100644
--- a/lang/m2/libm2/catch.c
+++ b/lang/m2/libm2/catch.c
@@ -1,3 +1,13 @@
+/*
+  (c) copyright 1988 by the Vrije Universiteit, Amsterdam, The Netherlands.
+  See the copyright notice in the ACK home directory, in the file "Copyright".
+*/
+
+/*
+  Module:	default modula-2 trap handler
+  Author:	Ceriel J.H. Jacobs
+  Version:	$Header$
+*/
 #include <em_abs.h>
 #include <m2_traps.h>
 
diff --git a/lang/m2/libm2/confarray.c b/lang/m2/libm2/confarray.c
index 2e89d8dbe..204ae69a3 100644
--- a/lang/m2/libm2/confarray.c
+++ b/lang/m2/libm2/confarray.c
@@ -1,3 +1,13 @@
+/*
+  (c) copyright 1988 by the Vrije Universiteit, Amsterdam, The Netherlands.
+  See the copyright notice in the ACK home directory, in the file "Copyright".
+*/
+
+/*
+  Module:	runtime support for conformant arrays
+  Author:	Ceriel J.H. Jacobs
+  Version:	$Header$
+*/
 #include <m2_traps.h>
 
 struct descr {
diff --git a/lang/m2/libm2/halt.c b/lang/m2/libm2/halt.c
index d9571a191..f07035093 100644
--- a/lang/m2/libm2/halt.c
+++ b/lang/m2/libm2/halt.c
@@ -1,3 +1,13 @@
+/*
+  (c) copyright 1988 by the Vrije Universiteit, Amsterdam, The Netherlands.
+  See the copyright notice in the ACK home directory, in the file "Copyright".
+*/
+
+/*
+  Module:	program termination routines
+  Author:	Ceriel J.H. Jacobs
+  Version:	$Header$
+*/
 #define MAXPROCS 16
 
 static int callindex;
diff --git a/lang/m2/libm2/head_m2.e b/lang/m2/libm2/head_m2.e
index b990ddfbd..c9bfc2a23 100644
--- a/lang/m2/libm2/head_m2.e
+++ b/lang/m2/libm2/head_m2.e
@@ -1,22 +1,13 @@
 #
-/*
- * (c) copyright 1983 by the Vrije Universiteit, Amsterdam, The Netherlands.
- *
- *          This product is part of the Amsterdam Compiler Kit.
- *
- * Permission to use, sell, duplicate or disclose this software must be
- * obtained in writing. Requests for such permissions may be sent to
- *
- *      Dr. Andrew S. Tanenbaum
- *      Wiskundig Seminarium
- *      Vrije Universiteit
- *      Postbox 7161
- *      1007 MC Amsterdam
- *      The Netherlands
- *
- */
-
-/* Author: C.J.H. Jacobs */
+;
+; (c) copyright 1988 by the Vrije Universiteit, Amsterdam, The Netherlands.
+; See the copyright notice in the ACK home directory, in the file "Copyright".
+;
+;
+; Module:	Modula-2 runtime startoff
+; Author:	Ceriel J.H. Jacobs
+; Version:	$Header$
+;
 
  mes 2,EM_WSIZE,EM_PSIZE
 
diff --git a/lang/m2/libm2/load.c b/lang/m2/libm2/load.c
index f88e9a6db..893b33c47 100644
--- a/lang/m2/libm2/load.c
+++ b/lang/m2/libm2/load.c
@@ -1,3 +1,13 @@
+/*
+  (c) copyright 1988 by the Vrije Universiteit, Amsterdam, The Netherlands.
+  See the copyright notice in the ACK home directory, in the file "Copyright".
+*/
+
+/*
+  Module:	get value on stack, byte by byte
+  Author:	Ceriel J.H. Jacobs
+  Version:	$Header$
+*/
 _load(siz, addr, p)
 	register char *addr;
 	register int siz;
diff --git a/lang/m2/libm2/random.def b/lang/m2/libm2/random.def
index 44d31f77c..d79e0d346 100644
--- a/lang/m2/libm2/random.def
+++ b/lang/m2/libm2/random.def
@@ -1,4 +1,9 @@
 DEFINITION MODULE random;
+(*
+  Module:	random numbers
+  Author:	Ceriel J.H. Jacobs
+  Version:	$Header$
+*)
 
 PROCEDURE Random(): CARDINAL;
 (* Return a random CARDINAL
@@ -9,4 +14,9 @@ PROCEDURE Uniform (lwb, upb: CARDINAL): CARDINAL;
    "lwb" must be smaller than "upb", or "lwb" is returned.
 *)
 
+PROCEDURE StartSeed(seed: CARDINAL);
+(* Initialize the generator. You don't have to call this procedure, unless
+   you don't want the system to pick a starting value for itself.
+*)
+
 END random.
diff --git a/lang/m2/libm2/random.mod b/lang/m2/libm2/random.mod
index ca6fb3401..ef983c83a 100644
--- a/lang/m2/libm2/random.mod
+++ b/lang/m2/libm2/random.mod
@@ -1,5 +1,15 @@
+(*
+  (c) copyright 1988 by the Vrije Universiteit, Amsterdam, The Netherlands.
+  See the copyright notice in the ACK home directory, in the file "Copyright".
+*)
+
 (*$R-*)
 IMPLEMENTATION MODULE random;
+(*
+  Module:       random numbers
+  Author:       Ceriel J.H. Jacobs
+  Version:      $Header$
+*)
 
 FROM Unix IMPORT getpid, time;
 TYPE index = [0..54];
@@ -21,12 +31,17 @@ BEGIN
     	RETURN lwb + (Random() MOD (upb - lwb + 1));
 END Uniform;
 
+PROCEDURE StartSeed(seed: CARDINAL);
 BEGIN
-	X[0] := time(NIL);
-	X[0] := CARDINAL(getpid()) * X[0];
+	X[0] := seed;
 	FOR k := 1 TO 54 DO
 		X[k] := X[k-1] * 1297;
 	END;
 	k := 54;
 	j := 30;
+END StartSeed;
+
+BEGIN
+ 	X0 := time(NIL);
+	StartSeed(CARDINAL(getpid()) * X[0]);
 END random.
diff --git a/lang/m2/libm2/rcki.e b/lang/m2/libm2/rcki.e
index 57d2b7e9f..72df511f6 100644
--- a/lang/m2/libm2/rcki.e
+++ b/lang/m2/libm2/rcki.e
@@ -1,4 +1,13 @@
 #
+;
+; (c) copyright 1988 by the Vrije Universiteit, Amsterdam, The Netherlands.
+; See the copyright notice in the ACK home directory, in the file "Copyright".
+;
+;
+; Module:	range checks for INTEGER
+; Author:	Ceriel J.H. Jacobs
+; Version:	$Header$
+;
 #include <em_abs.h>
 
  mes 2,EM_WSIZE,EM_PSIZE
diff --git a/lang/m2/libm2/rckil.e b/lang/m2/libm2/rckil.e
index 5b373a7d0..88f461c9a 100644
--- a/lang/m2/libm2/rckil.e
+++ b/lang/m2/libm2/rckil.e
@@ -1,4 +1,13 @@
 #
+;
+; (c) copyright 1988 by the Vrije Universiteit, Amsterdam, The Netherlands.
+; See the copyright notice in the ACK home directory, in the file "Copyright".
+;
+;
+; Module:	range checks for LONGINTS
+; Author:	Ceriel J.H. Jacobs
+; Version:	$Header$
+;
 #include <em_abs.h>
 
  mes 2,EM_WSIZE,EM_PSIZE
diff --git a/lang/m2/libm2/rcku.e b/lang/m2/libm2/rcku.e
index ffb1c8c87..687ea51d0 100644
--- a/lang/m2/libm2/rcku.e
+++ b/lang/m2/libm2/rcku.e
@@ -1,4 +1,13 @@
 #
+;
+; (c) copyright 1988 by the Vrije Universiteit, Amsterdam, The Netherlands.
+; See the copyright notice in the ACK home directory, in the file "Copyright".
+;
+;
+; Module:	range checks for CARDINAL
+; Author:	Ceriel J.H. Jacobs
+; Version:	$Header$
+;
 #include <em_abs.h>
 
  mes 2,EM_WSIZE,EM_PSIZE
diff --git a/lang/m2/libm2/rckul.e b/lang/m2/libm2/rckul.e
index 6bac67c82..62fb78d18 100644
--- a/lang/m2/libm2/rckul.e
+++ b/lang/m2/libm2/rckul.e
@@ -1,4 +1,13 @@
 #
+;
+; (c) copyright 1988 by the Vrije Universiteit, Amsterdam, The Netherlands.
+; See the copyright notice in the ACK home directory, in the file "Copyright".
+;
+;
+; Module:	Range checks for LONGCARD
+; Author:	Ceriel J.H. Jacobs
+; Version:	$Header$
+;
 #include <em_abs.h>
 
  mes 2,EM_WSIZE,EM_PSIZE
diff --git a/lang/m2/libm2/stackprio.c b/lang/m2/libm2/stackprio.c
index a1fcd7ca6..c7b195300 100644
--- a/lang/m2/libm2/stackprio.c
+++ b/lang/m2/libm2/stackprio.c
@@ -1,3 +1,13 @@
+/*
+  (c) copyright 1988 by the Vrije Universiteit, Amsterdam, The Netherlands.
+  See the copyright notice in the ACK home directory, in the file "Copyright".
+*/
+
+/*
+  Module:	Dummy priority routines
+  Author:	Ceriel J.H. Jacobs
+  Version:	$Header$
+*/
 _stackprio(n)
 {
 }
diff --git a/lang/m2/libm2/store.c b/lang/m2/libm2/store.c
index 6a728785d..b306e879e 100644
--- a/lang/m2/libm2/store.c
+++ b/lang/m2/libm2/store.c
@@ -1,3 +1,13 @@
+/*
+  (c) copyright 1988 by the Vrije Universiteit, Amsterdam, The Netherlands.
+  See the copyright notice in the ACK home directory, in the file "Copyright".
+*/
+
+/*
+  Module:	store values from stack, byte by byte
+  Author:	Ceriel J.H. Jacobs
+  Version:	$Header$
+*/
 _store(siz, addr, p)
 	register char *addr;
 	register int siz;
diff --git a/lang/m2/libm2/transfer.e b/lang/m2/libm2/transfer.e
index 8d18160f1..65d693f25 100644
--- a/lang/m2/libm2/transfer.e
+++ b/lang/m2/libm2/transfer.e
@@ -1,4 +1,16 @@
 #
+;
+; (c) copyright 1988 by the Vrije Universiteit, Amsterdam, The Netherlands.
+; See the copyright notice in the ACK home directory, in the file "Copyright".
+;
+;
+; Module:	implementation of coroutines
+; Author:	Ceriel J.H. Jacobs
+; Version:	$Header$
+;
+; This version works for EM implementations that have a contiguous downwards
+; growing stack, on which data below the stack-pointer is not destroyed.
+;
 #include <em_mes.h>
 #include <m2_traps.h>