mirror of
https://github.com/fluencelabs/musl
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63 lines
1.5 KiB
C
63 lines
1.5 KiB
C
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/* origin: FreeBSD /usr/src/lib/msun/src/s_nexttowardf.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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#include "libm.h"
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#if LDBL_MANT_DIG == 53 && LDBL_MAX_EXP == 1024
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// FIXME
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#elif (LDBL_MANT_DIG == 64 || LDBL_MANT_DIG == 113) && LDBL_MAX_EXP == 16384
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#define LDBL_INFNAN_EXP (LDBL_MAX_EXP * 2 - 1)
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float nexttowardf(float x, long double y)
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{
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union IEEEl2bits uy;
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volatile float t;
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int32_t hx,ix;
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GET_FLOAT_WORD(hx, x);
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ix = hx & 0x7fffffff; /* |x| */
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uy.e = y;
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if (ix > 0x7f800000 ||
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(uy.bits.exp == LDBL_INFNAN_EXP &&
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((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 (float)y; /* x=y, return y */
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if (ix == 0) { /* x == 0 */
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SET_FLOAT_WORD(x, (uy.bits.sign<<31)|1); /* return +-minsubnormal */
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/* raise underflow flag */
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t = x*x;
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if (t == x)
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return t;
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return x;
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}
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if (hx >= 0 ^ x < y) /* x -= ulp */
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hx--;
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else /* x += ulp */
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hx++;
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ix = hx & 0x7f800000;
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if (ix >= 0x7f800000) /* overflow */
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return x+x;
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if (ix < 0x00800000) { /* underflow */
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/* raise underflow flag */
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t = x*x;
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if (t != x) {
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SET_FLOAT_WORD(x, hx);
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return x;
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}
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}
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SET_FLOAT_WORD(x, hx);
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return x;
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}
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#endif
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