newlib-cygwin/winsup/cygwin/math/nexttoward.c

48 lines
924 B
C

/**
* This file has no copyright assigned and is placed in the Public Domain.
* This file is part of the mingw-w64 runtime package.
* No warranty is given; refer to the file DISCLAIMER.PD within this package.
*/
/*
nexttoward.c
Contributed by Danny Smith <dannysmith@users.sourceforge.net>
No copyright claimed, absolutely no warranties.
2005-05-10
*/
#include <math.h>
double
nexttoward (double x, long double y)
{
union
{
double d;
unsigned long long ll;
} u;
long double xx = x;
if (isnan (y) || isnan (x))
return x + y;
if (xx == y)
/* nextafter (0.0, -O.0) should return -0.0. */
return y;
u.d = x;
if (x == 0.0)
{
u.ll = 1;
return y > 0.0L ? u.d : -u.d;
}
/* Non-extended encodings are lexicographically ordered,
with implicit "normal" bit. */
if (((x > 0.0) ^ (y > xx)) == 0)
u.ll++;
else
u.ll--;
return u.d;
}