|
Packit |
6c4009 |
/* s_nexttoward.c
|
|
Packit |
6c4009 |
* Conversion from s_nextafter.c by Ulrich Drepper, Cygnus Support,
|
|
Packit |
6c4009 |
* drepper@cygnus.com.
|
|
Packit |
6c4009 |
*/
|
|
Packit |
6c4009 |
|
|
Packit |
6c4009 |
/*
|
|
Packit |
6c4009 |
* ====================================================
|
|
Packit |
6c4009 |
* Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
|
|
Packit |
6c4009 |
*
|
|
Packit |
6c4009 |
* Developed at SunPro, a Sun Microsystems, Inc. business.
|
|
Packit |
6c4009 |
* Permission to use, copy, modify, and distribute this
|
|
Packit |
6c4009 |
* software is freely granted, provided that this notice
|
|
Packit |
6c4009 |
* is preserved.
|
|
Packit |
6c4009 |
* ====================================================
|
|
Packit |
6c4009 |
*/
|
|
Packit |
6c4009 |
|
|
Packit |
6c4009 |
#if defined(LIBM_SCCS) && !defined(lint)
|
|
Packit |
6c4009 |
static char rcsid[] = "$NetBSD: $";
|
|
Packit |
6c4009 |
#endif
|
|
Packit |
6c4009 |
|
|
Packit |
6c4009 |
/* IEEE functions
|
|
Packit |
6c4009 |
* nexttoward(x,y)
|
|
Packit |
6c4009 |
* return the next machine floating-point number of x in the
|
|
Packit |
6c4009 |
* direction toward y.
|
|
Packit |
6c4009 |
* Special cases:
|
|
Packit |
6c4009 |
*/
|
|
Packit |
6c4009 |
|
|
Packit |
6c4009 |
#include <errno.h>
|
|
Packit |
6c4009 |
#include <math.h>
|
|
Packit |
6c4009 |
#include <math-barriers.h>
|
|
Packit |
6c4009 |
#include <math_private.h>
|
|
Packit |
6c4009 |
#include <float.h>
|
|
Packit |
6c4009 |
|
|
Packit |
6c4009 |
double __nexttoward(double x, long double y)
|
|
Packit |
6c4009 |
{
|
|
Packit |
6c4009 |
int32_t hx,ix,iy;
|
|
Packit |
6c4009 |
uint32_t lx,hy,ly,esy;
|
|
Packit |
6c4009 |
|
|
Packit |
6c4009 |
EXTRACT_WORDS(hx,lx,x);
|
|
Packit |
6c4009 |
GET_LDOUBLE_WORDS(esy,hy,ly,y);
|
|
Packit |
6c4009 |
ix = hx&0x7fffffff; /* |x| */
|
|
Packit |
6c4009 |
iy = esy&0x7fff; /* |y| */
|
|
Packit |
6c4009 |
|
|
Packit |
6c4009 |
if(((ix>=0x7ff00000)&&((ix-0x7ff00000)|lx)!=0) || /* x is nan */
|
|
Packit |
6c4009 |
((iy>=0x7fff)&&(hy|ly)!=0)) /* y is nan */
|
|
Packit |
6c4009 |
return x+y;
|
|
Packit |
6c4009 |
if((long double) x==y) return y; /* x=y, return y */
|
|
Packit |
6c4009 |
if((ix|lx)==0) { /* x == 0 */
|
|
Packit |
6c4009 |
double u;
|
|
Packit |
6c4009 |
INSERT_WORDS(x,(esy&0x8000)<<16,1); /* return +-minsub */
|
|
Packit |
6c4009 |
u = math_opt_barrier (x);
|
|
Packit |
6c4009 |
u = u * u;
|
|
Packit |
6c4009 |
math_force_eval (u); /* raise underflow flag */
|
|
Packit |
6c4009 |
return x;
|
|
Packit |
6c4009 |
}
|
|
Packit |
6c4009 |
if(hx>=0) { /* x > 0 */
|
|
Packit |
6c4009 |
if (x > y) { /* x -= ulp */
|
|
Packit |
6c4009 |
if(lx==0) hx -= 1;
|
|
Packit |
6c4009 |
lx -= 1;
|
|
Packit |
6c4009 |
} else { /* x < y, x += ulp */
|
|
Packit |
6c4009 |
lx += 1;
|
|
Packit |
6c4009 |
if(lx==0) hx += 1;
|
|
Packit |
6c4009 |
}
|
|
Packit |
6c4009 |
} else { /* x < 0 */
|
|
Packit |
6c4009 |
if (x < y) { /* x -= ulp */
|
|
Packit |
6c4009 |
if(lx==0) hx -= 1;
|
|
Packit |
6c4009 |
lx -= 1;
|
|
Packit |
6c4009 |
} else { /* x > y, x += ulp */
|
|
Packit |
6c4009 |
lx += 1;
|
|
Packit |
6c4009 |
if(lx==0) hx += 1;
|
|
Packit |
6c4009 |
}
|
|
Packit |
6c4009 |
}
|
|
Packit |
6c4009 |
hy = hx&0x7ff00000;
|
|
Packit |
6c4009 |
if(hy>=0x7ff00000) {
|
|
Packit |
6c4009 |
double u = x+x; /* overflow */
|
|
Packit |
6c4009 |
math_force_eval (u);
|
|
Packit |
6c4009 |
__set_errno (ERANGE);
|
|
Packit |
6c4009 |
}
|
|
Packit |
6c4009 |
if(hy<0x00100000) {
|
|
Packit |
6c4009 |
double u = x*x; /* underflow */
|
|
Packit |
6c4009 |
math_force_eval (u); /* raise underflow flag */
|
|
Packit |
6c4009 |
__set_errno (ERANGE);
|
|
Packit |
6c4009 |
}
|
|
Packit |
6c4009 |
INSERT_WORDS(x,hx,lx);
|
|
Packit |
6c4009 |
return x;
|
|
Packit |
6c4009 |
}
|
|
Packit |
6c4009 |
weak_alias (__nexttoward, nexttoward)
|