(***********************************************************************)
(*                                                                     *)
(*                Modula_2 Compiler RealMath Library Module            *)
(*                                                                     *)
(*            Provides a number of mathematical                        *)
(*            functions and REAL/INTEGER conversions                   *)
(*                                                                     *)
(*                                                                     *)
(*       original module : ISO WG-13, March  1989                      *)
(*       modifications   : arcsin and arccos not implemented           *)
(*                                                                     *)
(***********************************************************************)


DEFINITION MODULE RealMath;
 
(* implementation is not FOREIGN for gpm-pc *)

   CONST
	PI   = 3.1415926535897932385;
	Exp1 = 2.7182818285450452354;

   PROCEDURE sqrt(x : REAL):REAL;
   (* Precondition  : x is defined and >=0.0
      Postcondition : returns the square root of x.
   *)

   PROCEDURE exp(x : REAL):REAL;
   (* Precondition  : x is defined.
      Postcondition : returns the exponential of x.   *)

   PROCEDURE ln(x : REAL):REAL;
   (* Precondition  : x is defined and >= 0.0.
      Postcondition : returns the natural logarithm of x.  *)

   PROCEDURE sin(theta: REAL):REAL;
   (* Precondition  : theta is defined and is an angle in radians. 
      Postcondition : returns the sine of theta.  *)

   PROCEDURE cos(theta: REAL):REAL;
   (* Precondition  : theta is defined and is an angle in radians. 
      Postcondition : returns the cosine of theta.  *)

   PROCEDURE tan(theta : REAL):REAL;
   (* Precondition  : theta is defined and is an angle in radians.
      Postcondition : returns the tangent of x.   *)


   PROCEDURE arctan(x : REAL):REAL;
   (* Precondition  : x is defined
      Postcondition : returns the arctangent of x expressed in radians.  *)


   PROCEDURE power(x, y: REAL):REAL;
   (* Precondition  : true
      Postcondition : returns an approximation of 'x' raised to
		      the power of 'y'.   *)


   PROCEDURE round(r : REAL):INTEGER;
   (* Precondition  : r is defined and the result is representable as an 
                      INTEGER.
      Postcondition : returns the INTEGER approximation = r.  *)

END RealMath.