mirror of
https://github.com/fluencelabs/musl
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78 lines
2.0 KiB
C
78 lines
2.0 KiB
C
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/* origin: FreeBSD /usr/src/lib/msun/src/s_nextafterl.c */
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/*
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* ====================================================
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* Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
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*
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* Developed at SunPro, a Sun Microsystems, Inc. business.
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* Permission to use, copy, modify, and distribute this
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* software is freely granted, provided that this notice
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* is preserved.
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* ====================================================
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*/
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/* IEEE functions
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* nextafter(x,y)
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* return the next machine floating-point number of x in the
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* direction toward y.
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* Special cases:
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*/
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#include "libm.h"
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#if LDBL_MANT_DIG == 53 && LDBL_MAX_EXP == 1024
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long double nextafterl(long double x, long double y)
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{
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return nextafter(x, y);
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}
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#elif (LDBL_MANT_DIG == 64 || LDBL_MANT_DIG == 113) && LDBL_MAX_EXP == 16384
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long double nextafterl(long double x, long double y)
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{
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volatile long double t;
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union IEEEl2bits ux, uy;
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ux.e = x;
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uy.e = y;
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if ((ux.bits.exp == 0x7fff && ((ux.bits.manh&~LDBL_NBIT)|ux.bits.manl) != 0) ||
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(uy.bits.exp == 0x7fff && ((uy.bits.manh&~LDBL_NBIT)|uy.bits.manl) != 0))
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return x+y; /* x or y is nan */
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if (x == y)
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return y; /* x=y, return y */
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if (x == 0.0) {
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/* return +-minsubnormal */
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ux.bits.manh = 0;
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ux.bits.manl = 1;
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ux.bits.sign = uy.bits.sign;
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/* raise underflow flag */
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t = ux.e*ux.e;
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if (t == ux.e)
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return t;
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return ux.e;
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}
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if(x > 0.0 ^ x < y) { /* x -= ulp */
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if (ux.bits.manl == 0) {
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if ((ux.bits.manh&~LDBL_NBIT) == 0)
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ux.bits.exp--;
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ux.bits.manh = (ux.bits.manh - 1) | (ux.bits.manh & LDBL_NBIT);
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}
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ux.bits.manl--;
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} else { /* x += ulp */
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ux.bits.manl++;
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if (ux.bits.manl == 0) {
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ux.bits.manh = (ux.bits.manh + 1) | (ux.bits.manh & LDBL_NBIT);
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if ((ux.bits.manh&~LDBL_NBIT)==0)
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ux.bits.exp++;
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}
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}
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if (ux.bits.exp == 0x7fff) /* overflow */
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return x+x;
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if (ux.bits.exp == 0) { /* underflow */
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mask_nbit_l(ux);
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/* raise underflow flag */
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t = ux.e * ux.e;
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if (t != ux.e)
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return ux.e;
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}
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return ux.e;
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}
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#endif
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