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/* origin: FreeBSD /usr/src/lib/msun/src/s_nexttoward.c */
/*
* ====================================================
* 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.
* ====================================================
*/
#include "libm.h"
#if LDBL_MANT_DIG == 53 && LDBL_MAX_EXP == 1024
double nexttoward(double x, long double y)
{
return nextafter(x, y);
}
#elif (LDBL_MANT_DIG == 64 || LDBL_MANT_DIG == 113) && LDBL_MAX_EXP == 16384
double nexttoward(double x, long double y)
{
union IEEEl2bits uy;
volatile double t;
int32_t hx,ix;
uint32_t lx;
EXTRACT_WORDS(hx, lx, x);
ix = hx & 0x7fffffff;
uy.e = y;
if ((ix >= 0x7ff00000 && ((ix-0x7ff00000)|lx) != 0) ||
(uy.bits.exp == 0x7fff && ((uy.bits.manh&~LDBL_NBIT)|uy.bits.manl) != 0))
return x + y; /* x or y is nan */
if (x == y)
return (double)y;
if (x == 0.0) {
INSERT_WORDS(x, uy.bits.sign<<31, 1); /* return +-minsubnormal */
/* raise underflow */
t = x * x;
if (t == x)
return t;
return x;
}
if (hx > 0.0 ^ x < y) { /* x -= ulp */
if (lx == 0)
hx--;
lx--;
} else { /* x += ulp */
lx++;
if (lx == 0)
hx++;
}
ix = hx & 0x7ff00000;
if (ix >= 0x7ff00000) /* overflow */
return x + x;
if (ix < 0x00100000) { /* underflow */
/* raise underflow flag */
t = x * x;
if (t != x) {
INSERT_WORDS(x, hx, lx);
return x;
}
}
INSERT_WORDS(x, hx, lx);
return x;
}
#endif
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