[pdp8.git] / sw / src / pascal / POWER.PS

FUNCTION POWER(X: REAL; Y: INTEGER): REAL ; (*Y >= 0*)
VAR W,Z: REAL; I: INTEGER;
BEGIN W := X; Z := 1; I := Y;
    WHILE I > 0 DO
    BEGIN (*Z*(W**I) = X ** Y*)
       IF ODD(I) THEN Z := Z*W;
       I := I DIV 2;
       W := SQR(W)
    END;
    (*Z = X**Y*)
    POWER := Z
END;
Commit	Line	Data
81e70d48 PH	1	FUNCTION POWER(X: REAL; Y: INTEGER): REAL ; (Y >= 0)
	2	VAR W,Z: REAL; I: INTEGER;
	3	BEGIN W := X; Z := 1; I := Y;
	4	WHILE I > 0 DO
	5	BEGIN (Z(WI) = X Y*)
	6	IF ODD(I) THEN Z := Z*W;
	7	I := I DIV 2;
	8	W := SQR(W)
	9	END;
	10	(Z = XY)
	11	POWER := Z
	12	END;