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/* origin: FreeBSD /usr/src/lib/msun/src/s_nextafterl.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.
* ====================================================
*/
/* IEEE functions
* nextafter(x,y)
* return the next machine floating-point number of x in the
* direction toward y.
* Special cases:
*/
#include "libm.h"
#if LDBL_MANT_DIG == 53 && LDBL_MAX_EXP == 1024
long double nextafterl(long double x, long double y)
{
return nextafter(x, y);
}
#elif (LDBL_MANT_DIG == 64 || LDBL_MANT_DIG == 113) && LDBL_MAX_EXP == 16384
long double nextafterl(long double x, long double y)
{
volatile long double t;
union IEEEl2bits ux, uy;
ux.e = x;
uy.e = y;
if ((ux.bits.exp == 0x7fff && ((ux.bits.manh&~LDBL_NBIT)|ux.bits.manl) != 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 y; /* x=y, return y */
if (x == 0.0) {
/* return +-minsubnormal */
ux.bits.manh = 0;
ux.bits.manl = 1;
ux.bits.sign = uy.bits.sign;
/* raise underflow flag */
t = ux.e*ux.e;
if (t == ux.e)
return t;
return ux.e;
}
if(x > 0.0 ^ x < y) { /* x -= ulp */
if (ux.bits.manl == 0) {
if ((ux.bits.manh&~LDBL_NBIT) == 0)
ux.bits.exp--;
ux.bits.manh = (ux.bits.manh - 1) | (ux.bits.manh & LDBL_NBIT);
}
ux.bits.manl--;
} else { /* x += ulp */
ux.bits.manl++;
if (ux.bits.manl == 0) {
ux.bits.manh = (ux.bits.manh + 1) | (ux.bits.manh & LDBL_NBIT);
if ((ux.bits.manh&~LDBL_NBIT)==0)
ux.bits.exp++;
}
}
if (ux.bits.exp == 0x7fff) /* overflow */
return x+x;
if (ux.bits.exp == 0) { /* underflow */
mask_nbit_l(ux);
/* raise underflow flag */
t = ux.e * ux.e;
if (t != ux.e)
return ux.e;
}
return ux.e;
}
#endif
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