68 lines
1.7 KiB
C
68 lines
1.7 KiB
C
/* s_nextafterf.c -- float version of s_nextafter.c.
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* Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.com.
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*/
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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 "cdefs-compat.h"
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//__FBSDID("$FreeBSD: src/lib/msun/src/s_nextafterf.c,v 1.11 2008/02/22 02:30:35 das Exp $");
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#include <openlibm_math.h>
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#include "math_private.h"
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OLM_DLLEXPORT float
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nextafterf(float x, float y)
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{
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volatile float t;
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int32_t hx,hy,ix,iy;
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GET_FLOAT_WORD(hx,x);
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GET_FLOAT_WORD(hy,y);
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ix = hx&0x7fffffff; /* |x| */
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iy = hy&0x7fffffff; /* |y| */
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if((ix>0x7f800000) || /* x is nan */
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(iy>0x7f800000)) /* y is nan */
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return x+y;
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if(x==y) return y; /* x=y, return y */
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if(ix==0) { /* x == 0 */
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SET_FLOAT_WORD(x,(hy&0x80000000)|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 > 0 */
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if(hx>hy) { /* x > y, x -= ulp */
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hx -= 1;
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} else { /* x < y, x += ulp */
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hx += 1;
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}
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} else { /* x < 0 */
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if(hy>=0||hx>hy){ /* x < y, x -= ulp */
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hx -= 1;
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} else { /* x > y, x += ulp */
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hx += 1;
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}
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}
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hy = hx&0x7f800000;
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if(hy>=0x7f800000) return x+x; /* overflow */
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if(hy<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(y,hx);
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return y;
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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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