Integer Pascal for the NASCOM Computer
======================================

The Compiler runs with NASSYS1 in 1000H..3200H and needs at least 
16K memory. This pascal compiler uses integer variables in the range
of -32767 to +32767. 
He has a small, strange line editor and a code generator for a user 
defined code area. If the Compiler runs on NAS-SYS 1, then an automatic 
keyboard repeat feature helps editing the pascal source.

Start the compiler:
E1000 <p1> <p2> 
   if p1 is given, the compiler starts cold, else starts warm.
   p1	: start of source buffer
   p2	: end of source buffer

   working sample:
   ---------------
   E1000 4000 5000
   A0010 BEGIN
   A0020   WRITELN('HELLO WORLD');
   A0030 END.
   
   CC000				; Compile to address C000
   T					; Terminate
   EC000				; Execute the compiled program 
   					; and return to Integer Pascal

commands:
  Annnn data	: Append a line with number nnnn and content data.
  B		: Goto source begin
  C		: Compile the source for checking the syntax
  Cmmmm		: Compile to address mmmm
  Dnnnn		: Delete line number nnnn
  P		: Print Source file to printer
  Rnnnn data	: Replace Line with new content
  S		: Write Source file to tape (not nassys format)
  T		: Teminate Integer Compiler. If terminated, the automatic
  		: repeat feature don't work any more, until a cold start 
		: is done.
  Lnnnn		: List Source line nnnn
  Nnnnn		: Rename Source lines with nnnn increment
  
 In addition to the standard pascal implementation there are a few 
 language extentions:
- PEEK, POKE, SHL (shift left), SHR (shift right), 
  ELSE (in CASE statement)
- the predefined array MEM represents the Z80 memory.

Sample Program:
---------------
A0010 CONST NL=%0D; { NAS-SYS }
A0020 VAR X   : ARRAY [100] OF INTEGER;
A0030     Y,Z : INTEGER;
A0040 PROCEDURE SORT(N);
A0050   PROCEDURE SRT(LEFT, RIGHT);
A0060   VAR A, B, C, D : INTEGER;
A0070   BEGIN
A0080     A:=LEFT; B:=RIGHT;
A0090     C:=X[(LEFT+RIGHT) DIV 2];
A0100     REPEAT
A0110       WHILE X[A] < C DO A:=A+1;
A0120       WHILE C > X[B] DO B:=B-1; 
A0130       BEGIN
A0140         D:=X[A]; X[A]:=X[B]; X[B]:=D;
A0150         A:=A+1; B:=B-1;
A0160       END
A0170     UNTIL A > B;
A0180     IF LEFT < B THEN SRT(LEFT, B);
A0190     IF A < RIGHT THEN SRT(A, RIGHT);
A0200   END;
A0210 BEGIN { OF SORT }
A0220   SRT(1,N);
A0230 END; { OF SORT }
A0240 PROCEDURE NEWLINE(X);
A0241 BEGIN
A0242   IF X MOD 8 = 0 THEN
A0243     WRITE (NL")
A0244   ELSE
A0245     WRITE (' ')
A0249 END;
A0250 BEGIN { OF MAIN }
A0260   WRITE('Enter values:',NL");
A0270   Y:=0;
A0280   REPEAT
A0290     Y:=Y+1;
A0300     READ (X[Y]);
A0310     NEWLINE(Y);
A0320   UNTIL X[Y]=0;
A0330   SORT(Y-1);
A0340   WRITE(NL",'sorted values are:',NL");
A0350   FOR Z:=1 TO Y-1 DO
A0360     BEGIN
A0370       WRITE(X[Z]);
A0380       NEWLINE(Z);
A0390     END
A0400  END.