Blame sysdeps/ieee754/flt-32/s_nextafterf.c

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/* 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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#if defined(LIBM_SCCS) && !defined(lint)
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static char rcsid[] = "$NetBSD: s_nextafterf.c,v 1.4 1995/05/10 20:48:01 jtc Exp $";
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#endif
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#include <errno.h>
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#include <math.h>
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#include <math-barriers.h>
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#include <math_private.h>
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#include <libm-alias-float.h>
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#include <float.h>
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float __nextafterf(float x, float y)
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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((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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	    float u;
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	    SET_FLOAT_WORD(x,(hy&0x80000000)|1);/* return +-minsubnormal */
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	    u = math_opt_barrier (x);
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	    u = u*u;
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	    math_force_eval (u);		/* raise underflow flag */
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	    return x;
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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) {
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	  float u = x+x;	/* overflow  */
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	  math_force_eval (u);
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	  __set_errno (ERANGE);
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	}
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	if(hy<0x00800000) {
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	    float u = x*x;			/* underflow */
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	    math_force_eval (u);		/* raise underflow flag */
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	    __set_errno (ERANGE);
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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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libm_alias_float (__nextafter, nextafter)