/* derived from /netlib/fdlibm */ /* @(#)s_ilogb.c 1.3 95/01/18 *//* * ==================================================== * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved. * * Developed at SunSoft, a Sun Microsystems, Inc. business. * Permission to use, copy, modify, and distribute this * software is freely granted, provided that this notice  * is preserved. * ==================================================== */ /* ilogb(double x) * return the binary exponent of non-zero x * ilogb(0) = 0x80000001 * ilogb(inf/NaN) = 0x7fffffff (no signal is raised) */ #include "fdlibm.h" 	int ilogb(double x){	int hx,lx,ix; 	hx  = (__HI(x))&0x7fffffff;	/* high word of x */	if(hx<0x00100000) {	    lx = __LO(x);	    if((hx|lx)==0) 		return 0x80000001;	/* ilogb(0) = 0x80000001 */	    else			/* subnormal x */		if(hx==0) {		    for (ix = -1043; lx>0; lx<<=1) ix -=1;		} else {		    for (ix = -1022,hx<<=11; hx>0; hx<<=1) ix -=1;		}	    return ix;	}	else if (hx<0x7ff00000) return (hx>>20)-1023;	else return 0x7fffffff;}