1  /* s_modff.c -- float version of s_modf.c.
       2   */
       3  
       4  /*
       5   * ====================================================
       6   * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
       7   *
       8   * Developed at SunPro, a Sun Microsystems, Inc. business.
       9   * Permission to use, copy, modify, and distribute this
      10   * software is freely granted, provided that this notice
      11   * is preserved.
      12   * ====================================================
      13   */
      14  
      15  #include <math.h>
      16  #include <math_private.h>
      17  #include <libm-alias-float.h>
      18  
      19  static const float one = 1.0;
      20  
      21  float
      22  __modff(float x, float *iptr)
      23  {
      24  	int32_t i0,j0;
      25  	uint32_t i;
      26  	GET_FLOAT_WORD(i0,x);
      27  	j0 = ((i0>>23)&0xff)-0x7f;	/* exponent of x */
      28  	if(__builtin_expect(j0<23, 1)) {		/* integer part in x */
      29  	    if(j0<0) {			/* |x|<1 */
      30  		SET_FLOAT_WORD(*iptr,i0&0x80000000);	/* *iptr = +-0 */
      31  		return x;
      32  	    } else {
      33  		i = (0x007fffff)>>j0;
      34  		if((i0&i)==0) {			/* x is integral */
      35  		    uint32_t ix;
      36  		    *iptr = x;
      37  		    GET_FLOAT_WORD(ix,x);
      38  		    SET_FLOAT_WORD(x,ix&0x80000000);	/* return +-0 */
      39  		    return x;
      40  		} else {
      41  		    SET_FLOAT_WORD(*iptr,i0&(~i));
      42  		    return x - *iptr;
      43  		}
      44  	    }
      45  	} else {			/* no fraction part */
      46  	    *iptr = x*one;
      47  	    /* We must handle NaNs separately.  */
      48  	    if (j0 == 0x80 && (i0 & 0x7fffff))
      49  	      return x*one;
      50  	    SET_FLOAT_WORD(x,i0&0x80000000);	/* return +-0 */
      51  	    return x;
      52  	}
      53  }
      54  libm_alias_float (__modf, modf)