Oberon/ETH Oberon/PPPTools.Mod

(* ETH Oberon, Copyright 1990-2003 Computer Systems Institute, ETH Zurich, CH-8092 Zurich.
Refer to the license.txt file provided with this distribution. *)

MODULE PPPTools;	(** non-portable *)
(* $VCS   1, Edgar.Schwarz@z.zgs.de, 28 Feb 99, 22:9:47 $
    $Log$
$   1, Edgar.Schwarz@z.zgs.de, 28 Feb 99, 22:9:47
version for PPP 1.0.0
*)
IMPORT
	SYSTEM, PT := (*es*) NetBase, NetIP (*PacketTools*), Debug := PPPDebug;

CONST
	GoodFCS = - 0F48H;	(* 0F0B8H *)
		InitialFCS = - 1H;	(* 0FFFFH *)

VAR
	FCSTable: ARRAY 256 OF INTEGER;
		
PROCEDURE XOR(a, b:INTEGER): INTEGER;
BEGIN RETURN SYSTEM.VAL(INTEGER, (SYSTEM.VAL(SET, LONG(a)) / SYSTEM.VAL(SET, LONG(b))))
END XOR;

(*es*) (* aktiviert *)
PROCEDURE FCS (VAR a: ARRAY OF CHAR; pos, len: INTEGER): INTEGER;
VAR code, i: INTEGER;	(* we use 16 bit chksum *)
BEGIN
	code := InitialFCS;
	FOR i := pos TO pos+len-1 DO
		code := XOR(SYSTEM.LSH(code, - 8), FCSTable[SYSTEM.VAL(INTEGER, 
			SYSTEM.VAL(SET, LONG(XOR(code, SYSTEM.VAL(SHORTINT, a[i])))) * {0..7})])
	END;
	RETURN code
END FCS;
(**)

PROCEDURE CalcFCS16;
BEGIN
END CalcFCS16;
(*
PROCEDURE -CalcFCS16
	43H, 0F1H, 10H, 00H,					(* LEA 0(A1, D1.W), D1 *)
	70H, 0FFH,									(* MOVEQ #-1, D0 *)
	4AH, 42H,									(* TST.W D2 *)
	67H, 14H,									(* BEQ.S end *)
	53H, 42H,									(* SUBQ.W #1, D2 *)
	12H, 19H,									(* MOVE.B (A1)+, D1 *)
	0B1H, 41H,								(* EOR.W D0, D1 *)
	0E0H, 48H,									(* LSR.W #8, D0 *)
	02H, 41H, 00H, 0FFH,				(* ANDI.W #$00FF, D1 *)
	32H, 30H, 12H, 00H,					(* MOVE.W 0(A0, D1.W*2), D1*)
	0B3H, 40H,									(* EOR.W D1, D0 *)
	60H, 0E8H;									(* BRA.S loop1 *)
*)
(*es*) (*
PROCEDURE FCS (VAR a: ARRAY OF CHAR; pos, len: INTEGER): INTEGER;
CONST 
	D0 = 0; D1 = 1; D2 = 2; A0 = 8; A1 = 9;
VAR code: INTEGER;	
BEGIN
	SYSTEM.PUTREG(A0, SYSTEM.ADR(FCSTable)); SYSTEM.PUTREG(A1, SYSTEM.ADR(a));
	SYSTEM.PUTREG(D1, pos); SYSTEM.PUTREG(D2, len);
	CalcFCS16;
	SYSTEM.GETREG(D0, code);
	RETURN code
END FCS;
*)
(** CalcFCS - Calculates the FCS, should include Flag, Address etc., 
but no EscCodes, Space for FCS.. *)
PROCEDURE CalcFCS* (VAR a: ARRAY OF CHAR; pos, len: INTEGER): INTEGER;
BEGIN RETURN XOR(FCS(a, pos, len), -1)
END CalcFCS;

(* CheckFCS - Checks a complete packet, including Flag, Address AND FCS-Code! Returns TRUE if Packet is ok *)
PROCEDURE CheckFCS* (VAR a: ARRAY OF CHAR; pos, len: INTEGER): BOOLEAN;
BEGIN RETURN GoodFCS = FCS(a, pos, len)
END CheckFCS;
	
PROCEDURE GenerateFCSTab;
CONST P = - 7BF8H;	(* 8408H *)
VAR b, v, i:INTEGER;
BEGIN
	FOR b := 0 TO 255 DO v := b;
		FOR i:= 0 TO 7 DO
			IF ODD(v) THEN v := XOR(SYSTEM.LSH(v, -1), P) ELSE v := SYSTEM.LSH(v, -1) END
		END;
		FCSTable[b] := v
	END
END GenerateFCSTab;

(*---*)
		
PROCEDURE PutInt* (x: INTEGER; VAR p: ARRAY OF CHAR; pos: INTEGER);
BEGIN
	p[pos + 0] := CHR(SYSTEM.LSH(x, -8) MOD 256);
	p[pos + 1] := CHR(x MOD 256)
END PutInt;
	
PROCEDURE GetInt* (VAR p: ARRAY OF CHAR; pos: INTEGER): INTEGER;
BEGIN RETURN ORD(p[pos])*256 + ORD(p[pos + 1])
END GetInt;
	
PROCEDURE PutLong *(x: LONGINT; VAR p: ARRAY OF CHAR; pos: INTEGER);
BEGIN
	p[pos + 0] := CHR(SYSTEM.LSH(x, -24) MOD 256);
	p[pos + 1] := CHR(SYSTEM.LSH(x, -16) MOD 256);
	p[pos + 2] := CHR(SYSTEM.LSH(x, -8) MOD 256);
	p[pos + 3] := CHR(x MOD 256)	
END PutLong;

PROCEDURE GetLong* (VAR p: ARRAY OF CHAR; pos: INTEGER): LONGINT;
BEGIN
	RETURN ((LONG(ORD(p[pos]))*256 + LONG(ORD(p[pos + 1])))*256 
		+ LONG(ORD(p[pos + 2])))*256 + LONG(ORD(p[pos + 3]))
END GetLong;
		
PROCEDURE GetSet* (VAR p: ARRAY OF CHAR; pos: INTEGER): SET;
BEGIN RETURN SYSTEM.VAL(SET, GetLong(p, pos))
END GetSet;
	
PROCEDURE PutSet* (x: SET; VAR p: ARRAY OF CHAR; pos: INTEGER);
BEGIN PutLong(SYSTEM.VAL(LONGINT, x), p, pos)
END PutSet;

PROCEDURE GetIP* (VAR p: ARRAY OF CHAR; pos: INTEGER; 
								   VAR x: (*es*)NetIP.Adr(*PT.IPAdr*));
VAR i: INTEGER;
BEGIN FOR i := 0 TO (*es*)NetIP.AdrLen(*PT.IPAdrLen*) - 1 DO x[i] := p[pos + i] END
END GetIP;
	
PROCEDURE PutIP* (VAR x: (*es*)NetIP.Adr(*PT.IPAdr*); VAR p: ARRAY OF CHAR; pos: INTEGER);
VAR i: INTEGER;
BEGIN
	FOR i := 0 TO (*es*)NetIP.AdrLen(*PT.IPAdrLen*) - 1 DO 
		p[pos + i] := SYSTEM.VAL(CHAR,x[i])(*x[i]*) 
	END
END PutIP;
	
PROCEDURE EqualIP* (VAR p: ARRAY OF CHAR; pos: INTEGER; 
									VAR x: (*es*)NetIP.Adr(*PT.IPAdr*)): BOOLEAN;
VAR i: INTEGER;
BEGIN i := 0;
	WHILE (i # (*es*)NetIP.AdrLen(*PT.IPAdrLen*)) 
				& ((*es*)SYSTEM.VAL(CHAR,x[i])(*x[i]*) = p[pos + i]) DO 
		INC(i) 
	END;
	RETURN i = (*es*)NetIP.AdrLen(*PT.IPAdrLen*)
END EqualIP;
	
PROCEDURE CopyString* (VAR a: ARRAY OF CHAR; posfrom, posto, len: INTEGER);
VAR i: INTEGER;
BEGIN
	IF posfrom > posto THEN		FOR i := 0 TO len - 1 DO a[posto + i] := a[posfrom + i] END
	ELSIF posfrom < posto THEN  FOR i := len - 1 TO 0 BY - 1 DO a[posto + i] := a[posfrom + i] END
	END
END CopyString;
	
PROCEDURE Magic* (): LONGINT;
BEGIN RETURN 0;
END Magic;
	
PROCEDURE OutPacket* (VAR p: ARRAY OF CHAR; pos, len: INTEGER);
VAR i: INTEGER;
BEGIN
	FOR i := 0 TO len - 1 DO
		Debug.HexByte(p[pos + i]); 
		IF i MOD   4 = 3 THEN Debug.String(" "); END;
		IF i MOD 16 = 15 THEN Debug.Ln END;
	END;
	(*
	FOR i := 0 TO len BY 4 DO
		Debug.Hex(SYSTEM.VAL(LONGINT, p[pos + i])); Debug.String(" ");
		IF i MOD 16 = 0 THEN Debug.Ln END
	END;
	*)
	IF i MOD 16 # 0 THEN Debug.Ln END  (* Avoid redundant line break. *)
	(* Debug.Ln *)
END OutPacket;
	
PROCEDURE WriteSet*(s:SET; VAR a:ARRAY OF CHAR);
VAR k,i:INTEGER;
BEGIN k:=0;
	FOR i:=31 TO 0 BY -1 DO	IF (i IN s) THEN a[k]:="1"; ELSE a[k]:="0";  END; INC(k); END; a[k]:=0X;
END WriteSet;

BEGIN
	GenerateFCSTab
END PPPTools.