81 lines
2.1 KiB
C
81 lines
2.1 KiB
C
/* @(#)s_nextafter.c 5.1 93/09/24 */
|
|
/*
|
|
* ====================================================
|
|
* 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 "cdefs-compat.h"
|
|
//__FBSDID("$FreeBSD: src/lib/msun/src/s_nextafterl.c,v 1.2 2008/02/22 02:30:36 das Exp $");
|
|
|
|
/* IEEE functions
|
|
* nextafter(x,y)
|
|
* return the next machine floating-point number of x in the
|
|
* direction toward y.
|
|
* Special cases:
|
|
*/
|
|
|
|
#include <float.h>
|
|
#include <openlibm_math.h>
|
|
|
|
#include "fpmath.h"
|
|
#include "math_private.h"
|
|
|
|
#if LDBL_MAX_EXP != 0x4000
|
|
#error "Unsupported long double format"
|
|
#endif
|
|
|
|
OLM_DLLEXPORT 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) {
|
|
ux.bits.manh = 0; /* return +-minsubnormal */
|
|
ux.bits.manl = 1;
|
|
ux.bits.sign = uy.bits.sign;
|
|
t = ux.e*ux.e;
|
|
if(t==ux.e) return t; else return ux.e; /* raise underflow flag */
|
|
}
|
|
if((x>0.0) ^ (x<y)) { /* x -= ulp */
|
|
if(ux.bits.manl==0) {
|
|
if ((ux.bits.manh&~LDBL_NBIT)==0)
|
|
ux.bits.exp -= 1;
|
|
ux.bits.manh = (ux.bits.manh - 1) | (ux.bits.manh & LDBL_NBIT);
|
|
}
|
|
ux.bits.manl -= 1;
|
|
} else { /* x += ulp */
|
|
ux.bits.manl += 1;
|
|
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 += 1;
|
|
}
|
|
}
|
|
if(ux.bits.exp==0x7fff) return x+x; /* overflow */
|
|
if(ux.bits.exp==0) { /* underflow */
|
|
mask_nbit_l(ux);
|
|
t = ux.e * ux.e;
|
|
if(t!=ux.e) /* raise underflow flag */
|
|
return ux.e;
|
|
}
|
|
return ux.e;
|
|
}
|
|
|
|
openlibm_strong_reference(nextafterl, nexttowardl);
|