70 lines
1.8 KiB
C
70 lines
1.8 KiB
C
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/* $NetBSD: s_nexttowardf.c,v 1.3 2013/02/09 23:14:44 christos Exp $ */
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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 <sys/cdefs.h>
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#if 0
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__FBSDID("$FreeBSD: src/lib/msun/src/s_nexttowardf.c,v 1.3 2011/02/10 07:38:38 das Exp $");
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#else
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__RCSID("$NetBSD: s_nexttowardf.c,v 1.3 2013/02/09 23:14:44 christos Exp $");
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#endif
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#include <string.h>
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#include <float.h>
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#include <machine/ieee.h>
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#include "math.h"
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#include "math_private.h"
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#ifdef EXT_EXP_INFNAN
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float
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nexttowardf(float x, long double y)
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{
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volatile float t;
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int32_t hx,ix;
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union ieee_ext_u uy;
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GET_FLOAT_WORD(hx,x);
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ix = hx&0x7fffffff; /* |x| */
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memset(&uy, 0, sizeof(uy));
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uy.extu_ld = y;
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uy.extu_ext.ext_frach &= ~0x80000000;
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if((ix>0x7f800000) ||
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(uy.extu_ext.ext_exp == EXT_EXP_INFNAN &&
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(uy.extu_ext.ext_frach | uy.extu_ext.ext_fracl) != 0))
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return x+y; /* x or y is nan */
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if(x==y) 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.extu_ext.ext_sign<<31)|1);/* return +-minsubnormal */
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t = x*x;
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if(t==x) return t; else return x; /* raise underflow flag */
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}
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if((hx >= 0) ^ (x < y)) /* x -= ulp */
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hx -= 1;
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else /* x += ulp */
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hx += 1;
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ix = hx&0x7f800000;
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if(ix>=0x7f800000) return x+x; /* overflow */
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if(ix<0x00800000) { /* underflow */
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t = x*x;
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if(t!=x) { /* raise underflow flag */
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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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