newlib/winsup/mingw/mingwex/math/nexttoward.c

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/*
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;
}