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/*
nextafterl.c
Contributed by Danny Smith <dannysmith@users.sourceforge.net>
No copyright claimed, absolutely no warranties.
2005-05-09
*/
#include <math.h>
long double
nextafterl (long double x, long double y)
{
union {
long double ld;
struct {
unsigned long long mantissa;
unsigned short expn;
unsigned short pad;
} __attribute__ ((packed)) parts;
} u;
/* The normal bit is explicit for long doubles, unlike
float and double. */
static const unsigned long long normal_bit = 0x8000000000000000ull;
if (isnan (y) || isnan (x))
return x + y;
if (x == y )
/* nextafter (0.0, -O.0) should return -0.0. */
return y;
u.ld = x;
if (x == 0.0L)
{
u.parts.mantissa = 1ull;
return y > 0.0L ? u.ld : -u.ld;
}
if (((x > 0.0L) ^ (y > x)) == 0)
{
u.parts.mantissa++;
if ((u.parts.mantissa & ~normal_bit) == 0ull)
u.parts.expn++;
}
else
{
if ((u.parts.mantissa & ~normal_bit) == 0ull)
u.parts.expn--;
u.parts.mantissa--;
}
/* If we have updated the expn of a normal number,
or moved from denormal to normal, [re]set the normal bit. */
if (u.parts.expn & 0x7fff)
u.parts.mantissa |= normal_bit;
return u.ld;
}
/* nexttowardl is the same function with a different name. */
long double
nexttowardl (long double, long double) __attribute__ ((alias("nextafterl")));
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