/* derived from /netlib/fdlibm */ /* @(#)s_nextafter.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. * ==================================================== */ /* IEEE functions *	nextafter(x,y) *	return the next machine floating-point number of x in the *	direction toward y. *   Special cases: */ #include "fdlibm.h" 	double nextafter(double x, double y){	int	hx,hy,ix,iy;	unsigned lx,ly; 	hx = __HI(x);		/* high word of x */	lx = __LO(x);		/* low  word of x */	hy = __HI(y);		/* high word of y */	ly = __LO(y);		/* low  word of y */	ix = hx&0x7fffffff;		/* |x| */	iy = hy&0x7fffffff;		/* |y| */ 	if(((ix>=0x7ff00000)&&((ix-0x7ff00000)|lx)!=0) ||   /* x is nan */ 	   ((iy>=0x7ff00000)&&((iy-0x7ff00000)|ly)!=0))     /* y is nan */ 	   return x+y;					if(x==y) return x;		/* x=y, return x */	if((ix|lx)==0) {			/* x == 0 */	    __HI(x) = hy&0x80000000;	/* return +-minsubnormal */	    __LO(x) = 1;	    y = x*x;	    if(y==x) return y; else return x;	/* raise underflow flag */	} 	if(hx>=0) {				/* x > 0 */	    if(hx>hy||((hx==hy)&&(lx>ly))) {	/* x > y, x -= ulp */		if(lx==0) hx -= 1;		lx -= 1;	    } else {				/* x < y, x += ulp */		lx += 1;		if(lx==0) hx += 1;	    }	} else {				/* x < 0 */	    if(hy>=0||hx>hy||((hx==hy)&&(lx>ly))){/* x < y, x -= ulp */		if(lx==0) hx -= 1;		lx -= 1;	    } else {				/* x > y, x += ulp */		lx += 1;		if(lx==0) hx += 1;	    }	}	hy = hx&0x7ff00000;	if(hy>=0x7ff00000) return x+x;	/* overflow  */	if(hy<0x00100000) {		/* underflow */	    y = x*x;	    if(y!=x) {		/* raise underflow flag */		__HI(y) = hx; __LO(y) = lx;		return y;	    }	}	__HI(x) = hx; __LO(x) = lx;	return x;}