DEFINITION MODULE CalcFunctions;

(*

   This module creates the functions for the calculator.
    This is the lowest level module.

    Four functions need the gadget information and are in the
     Module CalcGadgets. These functions are:
          STO
          RCL
          DEG    (toggles between degrees and radians)
          GOLD   (selects alternate gadgets in display)


   Created: Duncan Prindle,  September 10, 1986

   Modified: Perhaps

*)


TYPE  ErrorType = (NoError, DivideByZero, NegSqrt, NegLog, NegLn,
                   XTooBigForSIN, AsinTooBig, XTooBigForCOS, AcosTooBig,
                   XTooBigForTAN, OverFlow, piOver2, OtherError);

VAR
  X         : REAL;
  SAME      : BOOLEAN;
  DECI      : BOOLEAN;
  NDeci     : INTEGER;
  INDEG     : BOOLEAN;
  stored    : ARRAY[0..9] OF REAL;

 PROCEDURE BLANK (): ErrorType;
 PROCEDURE CLRStack;
 PROCEDURE StackUp;
 PROCEDURE StackDown;
 PROCEDURE Add (): ErrorType;
 PROCEDURE Subtract (): ErrorType;
 PROCEDURE Multiply (): ErrorType;
 PROCEDURE Divide (): ErrorType;
 PROCEDURE POINT (): ErrorType;
 PROCEDURE PI (): ErrorType;
 PROCEDURE CLX (): ErrorType;
 PROCEDURE RDN (): ErrorType;
 PROCEDURE ENTER (): ErrorType;
 PROCEDURE LASTX (): ErrorType;
 PROCEDURE SIN (): ErrorType;
 PROCEDURE ASIN (): ErrorType;
 PROCEDURE COS (): ErrorType;
 PROCEDURE ACOS (): ErrorType;
 PROCEDURE TAN (): ErrorType;
 PROCEDURE ATAN (): ErrorType;
 PROCEDURE LN (): ErrorType;
 PROCEDURE EXP (): ErrorType;
 PROCEDURE TENtotheX (): ErrorType;
 PROCEDURE LOG (): ErrorType;
 PROCEDURE YtotheX (): ErrorType;
 PROCEDURE OneOverX (): ErrorType;
 PROCEDURE XSquared (): ErrorType;
 PROCEDURE SQRT (): ErrorType;
 PROCEDURE XtoY (): ErrorType;
 PROCEDURE CHS (): ErrorType;
 PROCEDURE CLRST (): ErrorType;
 PROCEDURE EXTENDX( Digit: CARDINAL );

END CalcFunctions.