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      1 /* s_rintf.c -- float version of s_rint.c.
      2  * Conversion to float by Ian Lance Taylor, Cygnus Support, ian (at) cygnus.com.
      3  */
      4 
      5 /*
      6  * ====================================================
      7  * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
      8  *
      9  * Developed at SunPro, a Sun Microsystems, Inc. business.
     10  * Permission to use, copy, modify, and distribute this
     11  * software is freely granted, provided that this notice
     12  * is preserved.
     13  * ====================================================
     14  */
     15 
     16 #include <sys/cdefs.h>
     17 __FBSDID("$FreeBSD$");
     18 
     19 #include <float.h>
     20 #include <stdint.h>
     21 
     22 #include "math.h"
     23 #include "math_private.h"
     24 
     25 static const float
     26 TWO23[2]={
     27   8.3886080000e+06, /* 0x4b000000 */
     28  -8.3886080000e+06, /* 0xcb000000 */
     29 };
     30 
     31 float
     32 rintf(float x)
     33 {
     34 	int32_t i0,j0,sx;
     35 	float w,t;
     36 	GET_FLOAT_WORD(i0,x);
     37 	sx = (i0>>31)&1;
     38 	j0 = ((i0>>23)&0xff)-0x7f;
     39 	if(j0<23) {
     40 	    if(j0<0) {
     41 		if((i0&0x7fffffff)==0) return x;
     42 		STRICT_ASSIGN(float,w,TWO23[sx]+x);
     43 	        t =  w-TWO23[sx];
     44 		GET_FLOAT_WORD(i0,t);
     45 		SET_FLOAT_WORD(t,(i0&0x7fffffff)|(sx<<31));
     46 	        return t;
     47 	    }
     48 	    STRICT_ASSIGN(float,w,TWO23[sx]+x);
     49 	    return w-TWO23[sx];
     50 	}
     51 	if(j0==0x80) return x+x;	/* inf or NaN */
     52 	else return x;			/* x is integral */
     53 }
     54