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/* s_rintf.c -- float version of s_rint.c.
 * Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.com.
 */

/*
 * ====================================================
 * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
 *
 * Developed at SunPro, a Sun Microsystems, Inc. business.
 * Permission to use, copy, modify, and distribute this
 * software is freely granted, provided that this notice
 * is preserved.
 * ====================================================
 */

#ifndef lint
static char rcsid[] = "$\Id: s_rintf.c,v 1.3 1996/08/28 16:34:36 bde Exp $";
#endif

#include "math.h"
#include "math_private.h"

/*
 * TWO23 is double instead of float to avoid a bug in gcc.  Without
 * this, gcc thinks that TWO23[sx]+x and w-TWO23[sx] already have float
 * precision and doesn't clip them to float precision when they are
 * assigned and returned.
 */
#ifdef __STDC__
static const double
#else
static double
#endif
TWO23[2]={
  8.3886080000e+06, /* 0x4b000000 */
 -8.3886080000e+06, /* 0xcb000000 */
};

#ifdef __STDC__
        float rintf(float x)
#else
        float rintf(x)
        float x;
#endif
{
        int32_t i0,j0,sx;
        u_int32_t i,i1;
        float w,t;
        GET_FLOAT_WORD(i0,x);
        sx = (i0>>31)&1;
        j0 = ((i0>>23)&0xff)-0x7f;
        if(j0<23) {
            if(j0<0) {
                if((i0&0x7fffffff)==0) return x;
                i1 = (i0&0x07fffff);
                i0 &= 0xfff00000;
                i0 |= ((i1|-i1)>>9)&0x400000;
                SET_FLOAT_WORD(x,i0);
                w = TWO23[sx]+x;
                t =  w-TWO23[sx];
                GET_FLOAT_WORD(i0,t);
                SET_FLOAT_WORD(t,(i0&0x7fffffff)|(sx<<31));
                return t;
            } else {
                i = (0x007fffff)>>j0;
                if((i0&i)==0) return x; /* x is integral */
                i>>=1;
                if((i0&i)!=0) i0 = (i0&(~i))|((0x100000)>>j0);
            }
        } else {
            if(j0==0x80) return x+x;    /* inf or NaN */
            else return x;              /* x is integral */
        }
        SET_FLOAT_WORD(x,i0);
        w = TWO23[sx]+x;
        return w-TWO23[sx];
}