Blame math/s_nexttowardf.c

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/* Single precision version of nexttoward.c.
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   Conversion to IEEE single float by Jakub Jelinek, jj@ultra.linux.cz. */
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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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/* IEEE functions
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 *	nexttowardf(x,y)
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 *	return the next machine floating-point number of x in the
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 *	direction toward y.
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 * This is for machines which use the same binary type for double and
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 * long double.
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 *   Special cases:
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 */
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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 <float.h>
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float __nexttowardf(float x, long double y)
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{
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	int32_t hx,hy,ix,iy;
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	uint32_t ly;
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	GET_FLOAT_WORD(hx,x);
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	EXTRACT_WORDS(hy,ly,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>=0x7ff00000)&&((iy-0x7ff00000)|ly)!=0))    /* y is nan */
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	   return x+y;
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	if((long double) 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,(uint32_t)(hy&0x80000000)|1);/* return +-minsub*/
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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(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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	} else {				/* x < 0 */
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	    if(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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	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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weak_alias (__nexttowardf, nexttowardf)