PROGRAM BOUNCY;

const box : array[0..63] of byte =
      (0,0,0,0,0,0,0,0,
       0,0,1,1,1,1,0,0,
       0,1,3,3,3,3,1,0,
       0,1,3,3,3,3,1,0,
       0,1,3,3,3,3,1,0,
       0,1,3,3,3,3,1,0,
       0,0,1,1,1,1,0,0,
       0,0,0,0,0,0,0,0);

var   address   : byte;
      CPM22     : integer absolute $BE9B;
      CPMPlus   : integer absolute $FC5A;

Procedure mode(mo:byte);
 begin
  if (address=$22) then
   Inline($3A/mo/
          $CD/CPM22/
          $0E/$BC)
  else
   Inline($3A/mo/
          $CD/CPMPlus/
          $0E/$BC);
 end;

Procedure TxtCurOff;
 begin
  if (address=$22) then
   Inline($CD/CPM22/
          $84/$BB)
  else
   Inline($CD/CPMPlus/
          $84/$BB);
 end;

Procedure TxtCurOn;
 begin
  IF (address=$22) then
   Inline($CD/CPM22/
          $81/$BB)
  else
   Inline($CD/CPMPlus/
          $81/$BB);
 end;

Procedure Draw(Xpos, Ypos : Integer);
 begin
  IF (address=$22) then
   Inline($2A/ypos/
          $ED/$5B/xpos/
          $CD/CPM22/
          $F6/$BB)
  else
   Inline($2A/ypos/
          $ED/$5B/xpos/
          $CD/CPMPlus/
          $F6/$BB);
 end;

Procedure Move(Xpos, Ypos : Integer);
 begin
  IF (address=$22) then
   Inline($2A/ypos/
          $ED/$5B/xpos/
          $CD/CPM22/
          $C0/$BB)
  else
   Inline($2A/ypos/
          $ED/$5B/xpos/
          $CD/CPMPlus/
          $C0/$BB);
 end;

Procedure resetcolor;
 begin
  IF (address=$22) then
   Inline($CD/CPM22/
          $02/$BC)
  else
   Inline($CD/CPMPlus/
          $02/$BC);
 end;

Procedure grapen(col:byte);
 begin
  IF (address=$22) then
   Inline($3A/col/
          $CD/CPM22/
          $DE/$BB)
  else
   Inline($3A/col/
          $CD/CPMPlus/
          $DE/$BB);
 end;

Procedure PlotPoint(xpos,ypos:integer);
 begin
  IF (address=$22) then
   Inline($2A/ypos/
          $ED/$5B/xpos/
          $CD/CPM22/
          $EA/$BB)
  else
   Inline($2A/ypos/
          $ED/$5B/xpos/
          $CD/CPMPlus/
          $EA/$BB);
 end;

Procedure Frame;
 begin
  IF (address=$22) then
   Inline($CD/CPM22/
          $19/$BD)
  else
   Inline($CD/CPMPlus/
          $19/$BD);
 end;

Procedure CheckCPM;
 begin
  IF (BDOS($0C)=34) Then
      Address:=$22
  else
      Address:=$31;
 end;

{ Main Procedures }

Procedure DrBox(Size : byte; Xpos, Ypos : integer);

var Length, Length2 : Integer;

Begin
 Length2:=0;
 Size:=16;
 For Length:=0 to 63 do
   begin
    GraPen(Box[Length]);
    PlotPoint(Xpos + Length2, Ypos + Size);
    Length2:=Length2+2;
    if Length2=16 then
     Begin
      Length2:=0;
      Size:=Size-2;
     end;
   end;
end;

Procedure DrawBox;
 Begin
 Grapen(2);
 Move(200,300);
 Draw(470,300);
 Draw(470,100);
 Draw(200,100);
 Draw(200,300);
 End;

Var Xpos, Xdir, Ypos, Ydir : integer;
    Width, Length : integer;

begin { Main Routine }
 CheckCPM;
 ResetColor;
 Mode(1);
 DrawBox;
 Xpos:=205;
 Ypos:=281;
 Xdir:=1;
 Ydir:=-1;
 Repeat
  TxtCuroff;
  Xpos:=Xpos+Xdir;
  Ypos:=Ypos+Ydir;
  DrBox(Box[Width],Xpos,Ypos);
 Case Xpos of
  450 : Xdir:=-1;
  204 : Xdir:=1;
 end;
 Case Ypos of
  280 : Ydir:=-1;
  104 : Ydir:=1;
 end;
  TxtCuroff;
 Until Keypressed;
  TxtCurOn;
  Mode(2);
End.