logb
double logb(double);
#define logb(a) __TG_FN1(logb, (a))
if((m=(k=logb(y))-logb(x)) > 60) t=big+big;
exp= logb(x);
if(exp-(int)logb(y) > ibig )
exp= logb(x);
if(exp-(int)logb(y) > ibig )
return (int)logb(x);
m = logb(x);
j = logb(g), m += j;
m = logb(x);
j = logb(g), m += j;
k=logb(one+x); z=scalb(x,-k); t=scalb(one,-k);
n=logb(x);
if((m=logb(x))!=0) x=scalb(x,-m); /* subnormal number */
m = logb(x);
j = logb(g), m += j;
__strong_alias(logbl,logb)
logb(double x)