80 lines
1.8 KiB
C
80 lines
1.8 KiB
C
/* sf_nextafter.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 "fdlibm.h"
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#ifdef __STDC__
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float nextafterf(float x, float y)
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#else
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float nextafterf(x,y)
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float x,y;
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#endif
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{
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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(FLT_UWORD_IS_NAN(ix) ||
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FLT_UWORD_IS_NAN(iy))
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return x+y;
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if(x==y) return x; /* x=y, return x */
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if(FLT_UWORD_IS_ZERO(ix)) { /* x == 0 */
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SET_FLOAT_WORD(x,(hy&0x80000000)|FLT_UWORD_MIN);
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y = x*x;
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if(y==x) return y; 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>FLT_UWORD_MAX) return x+x; /* overflow */
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if(hy<0x00800000) { /* underflow */
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y = x*x;
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if(y!=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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#ifdef _DOUBLE_IS_32BITS
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#ifdef __STDC__
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double nextafter(double x, double y)
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#else
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double nextafter(x,y)
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double x,y;
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#endif
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{
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return (double) nextafterf((float) x, (float) x);
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}
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#endif /* defined(_DOUBLE_IS_32BITS) */
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