Prevent the use of deprecated or internal functions if possible.

The finite() function has been superseded by isfinite(). There is also
no need to use scalb(), as the exponent is also an integer value. We can
simply use scalbn().

There is also no need to use __isnanf(). The values passed are
guaranteed to be of type float, meaning we can safely use the standard
isnan().

Author: EdSchouten

bsdsrc/b_exp.c

@@ -152,13 +152,13 @@ double x, c;
 			c= x - z*(p1+z*(p2+z*(p3+z*(p4+z*p5))));
 			c = (x*c)/(2.0-c);
 
-			return  scalb(1.+(hi-(lo - c)), k);
+			return  scalbn(1.+(hi-(lo - c)), k);
 		}
 		/* end of x > lntiny */
 
 		else
 		     /* exp(-big#) underflows to zero */
-		     if(finite(x))  return(scalb(1.0,-5000));
+		     if(isfinite(x))  return(scalbn(1.0,-5000));
 
 		     /* exp(-INF) is zero */
 		     else return(0.0);
@@ -167,5 +167,5 @@ double x, c;
 
 	else
 	/* exp(INF) is INF, exp(+big#) overflows to INF */
-	    return( finite(x) ?  scalb(1.0,5000)  : x);
+	    return( isfinite(x) ?  scalbn(1.0,5000)  : x);
 }

bsdsrc/b_tgamma.c

@@ -140,7 +140,7 @@ tgamma(x)
 		if (x != 0.0)
 			u.a = one - tiny;	/* raise inexact */
 		return (one/x);
-	} else if (!finite(x))
+	} else if (!isfinite(x))
 		return (x - x);		/* x is NaN or -Inf */
 	else
 		return (neg_gam(x));

src/e_scalb.c

@@ -35,7 +35,7 @@ __ieee754_scalb(double x, double fn)
 	return scalbn(x,fn);
 #else
 	if (isnan(x)||isnan(fn)) return x*fn;
-	if (!finite(fn)) {
+	if (!isfinite(fn)) {
 	    if(fn>0.0) return x*fn;
 	    else       return x/(-fn);
 	}

src/e_scalbf.c

@@ -30,8 +30,8 @@ __ieee754_scalbf(float x, float fn)
 #ifdef _SCALB_INT
 	return scalbnf(x,fn);
 #else
-	if ((__isnanf)(x)||(__isnanf)(fn)) return x*fn;
-	if (!finitef(fn)) {
+	if (isnan(x)||isnan(fn)) return x*fn;
+	if (!isfinite(fn)) {
 	    if(fn>(float)0.0) return x*fn;
 	    else       return x/(-fn);
 	}