PROCEDURE TEXTMODE; EXTERNAL $901F;
PROCEDURE GRAPHMODE; EXTERNAL $9010;
PROCEDURE PLOT (X,Y,C:INTEGER); EXTERNAL $901c;
PROCEDURE GRAPHBACKGROUND (C:INTEGER); EXTERNAL $9019;
PROCEDURE TEXTCOLOR (C:INTEGER); EXTERNAL $9016;
PROCEDURE TEXTBACKGROUND (C:INTEGER); EXTERNAL $9022;
FUNCTION WHEREX:INTEGER; EXTERNAL $9025;
FUNCTION WHEREY:INTEGER; EXTERNAL $9028;
PROCEDURE DRAW (X,Y,X1,Y1,C:INTEGER); EXTERNAL $902E;
PROCEDURE CIRCLE (X,Y,R,C:INTEGER); EXTERNAL $9013;
PROCEDURE FILLSCREEN (C:INTEGER); EXTERNAL $904C;
PROCEDURE GOTOXY(X,Y:INTEGER); EXTERNAL $902B;
PROCEDURE CLRSCR; EXTERNAL $9031;
PROCEDURE SOUND (F:INTEGER); EXTERNAL $903A;
PROCEDURE NOSOUND; EXTERNAL $903D;
FUNCTION HI(C:INTEGER):INTEGER; EXTERNAL $9040;
FUNCTION LO(C:INTEGER):INTEGER; EXTERNAL $9043;
FUNCTION SWAP(C:INTEGER):INTEGER; EXTERNAL $9046;
FUNCTION KEYPRESSED:BOOLEAN; EXTERNAL $9049;
PROCEDURE FILLSHAPE(X,Y,C:INTEGER); EXTERNAL $9037;
FUNCTION GETDOTCOLOR(X,Y:INTEGER):INTEGER; EXTERNAL $9034;