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      1 /* s_modff.c -- float version of s_modf.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 "math.h"
     20 #include "math_private.h"
     21 
     22 static const float one = 1.0;
     23 
     24 float
     25 modff(float x, float *iptr)
     26 {
     27 	int32_t i0,j0;
     28 	u_int32_t i;
     29 	GET_FLOAT_WORD(i0,x);
     30 	j0 = ((i0>>23)&0xff)-0x7f;	/* exponent of x */
     31 	if(j0<23) {			/* integer part in x */
     32 	    if(j0<0) {			/* |x|<1 */
     33 	        SET_FLOAT_WORD(*iptr,i0&0x80000000);	/* *iptr = +-0 */
     34 		return x;
     35 	    } else {
     36 		i = (0x007fffff)>>j0;
     37 		if((i0&i)==0) {			/* x is integral */
     38 		    u_int32_t ix;
     39 		    *iptr = x;
     40 		    GET_FLOAT_WORD(ix,x);
     41 		    SET_FLOAT_WORD(x,ix&0x80000000);	/* return +-0 */
     42 		    return x;
     43 		} else {
     44 		    SET_FLOAT_WORD(*iptr,i0&(~i));
     45 		    return x - *iptr;
     46 		}
     47 	    }
     48 	} else {			/* no fraction part */
     49 	    u_int32_t ix;
     50 	    *iptr = x*one;
     51 	    if (x != x)			/* NaN */
     52 		return x;
     53 	    GET_FLOAT_WORD(ix,x);
     54 	    SET_FLOAT_WORD(x,ix&0x80000000);	/* return +-0 */
     55 	    return x;
     56 	}
     57 }
     58