GENERIC INTERFACE IntegerPower(R);

Arithmetic for Modula-3, see doc for details

Abstract: Fast generic computation of a power with integer exponent

IMPORT Arithmetic AS Arith;

TYPE
  T = R.T;
  PositiveInteger = [1 .. LAST(CARDINAL)];

PROCEDURE Power (x: T; y: PositiveInteger; ): T RAISES {Arith.Error};

returns the power x^y with respect to the multiplication of R. This implementation needs only Log2(y) multiplications. Requires y>0 because R may not provide a unique One

PROCEDURE MulPower (x, y: T; z: CARDINAL; ): T RAISES {Arith.Error};

returns the x*y^z with respect to the multiplication of R. This is as fast as Power but works for z=0, too.

END IntegerPower.