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/* s_nexttoward.c
* Conversion from s_nextafter.c by Ulrich Drepper, Cygnus Support,
* drepper@cygnus.com and Jakub Jelinek, jj@ultra.linux.cz.
*/
/*
* ====================================================
* Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
*
* Developed at SunPro, a Sun Microsystems, Inc. business.
* Permission to use, copy, modify, and distribute this
* software is freely granted, provided that this notice
* is preserved.
* ====================================================
*/
#if defined(LIBM_SCCS) && !defined(lint)
static char rcsid[] = "$NetBSD: $";
#endif
/* IEEE functions
* nexttoward(x,y)
* return the next machine floating-point number of x in the
* direction toward y.
* Special cases:
*/
#include "math.h"
#include "math_private.h"
#ifdef __STDC__
double __nexttoward(double x, long double y)
#else
double __nexttoward(x,y)
double x;
long double y;
#endif
{
int32_t hx,ix;
int64_t hy,iy;
u_int32_t lx;
u_int64_t ly;
EXTRACT_WORDS(hx,lx,x);
GET_LDOUBLE_WORDS64(hy,ly,y);
ix = hx&0x7fffffff; /* |x| */
iy = hy&0x7fffffffffffffffLL; /* |y| */
if(((ix>=0x7ff00000)&&((ix-0x7ff00000)|lx)!=0) || /* x is nan */
((iy>=0x7fff000000000000LL)&&((iy-0x7fff000000000000LL)|ly)!=0))
/* y is nan */
return x+y;
if((long double) x==y) return x; /* x=y, return x */
if((ix|lx)==0) { /* x == 0 */
double x2;
INSERT_WORDS(x,(u_int32_t)((hy>>32)&0x80000000),1);/* return +-minsub */
x2 = x*x;
if(x2==x) return x2; else return x; /* raise underflow flag */
}
if(hx>=0) { /* x > 0 */
if (hy<0||(ix>>20)>(iy>>48)-0x3c00
|| ((ix>>20)==(iy>>48)-0x3c00
&& (((((int64_t)hx)<<28)|(lx>>4))>(hy&0x0000ffffffffffffLL)
|| (((((int64_t)hx)<<28)|(lx>>4))==(hy&0x0000ffffffffffffLL)
&& (lx&0xf)>(ly>>60))))) { /* 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||(ix>>20)>(iy>>48)-0x3c00
|| ((ix>>20)==(iy>>48)-0x3c00
&& (((((int64_t)hx)<<28)|(lx>>4))>(hy&0x0000ffffffffffffLL)
|| (((((int64_t)hx)<<28)|(lx>>4))==(hy&0x0000ffffffffffffLL)
&& (lx&0xf)>(ly>>60))))) { /* 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 */
double x2 = x*x;
if(x2!=x) { /* raise underflow flag */
INSERT_WORDS(x2,hx,lx);
return x2;
}
}
INSERT_WORDS(x,hx,lx);
return x;
}
weak_alias (__nexttoward, nexttoward)
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