1  /* Single precision version of nexttoward.c.
       2     Conversion to IEEE single float by Jakub Jelinek, jj@ultra.linux.cz. */
       3  /*
       4   * ====================================================
       5   * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
       6   *
       7   * Developed at SunPro, a Sun Microsystems, Inc. business.
       8   * Permission to use, copy, modify, and distribute this
       9   * software is freely granted, provided that this notice
      10   * is preserved.
      11   * ====================================================
      12   */
      13  
      14  /* IEEE functions
      15   *	__nexttowardfd(x,y)
      16   *	return the next machine floating-point number of x in the
      17   *	direction toward y.
      18   * This is for machines which use different binary type for double and
      19   * long double conditionally, y is long double equal to double.
      20   *   Special cases:
      21   */
      22  
      23  #include <errno.h>
      24  #include <math.h>
      25  #include <math-barriers.h>
      26  #include <math_private.h>
      27  #include <math_ldbl_opt.h>
      28  #include <float.h>
      29  
      30  float __nldbl_nexttowardf(float x, double y);
      31  
      32  float __nldbl_nexttowardf(float x, double y)
      33  {
      34  	int32_t hx,hy,ix,iy;
      35  	uint32_t ly;
      36  
      37  	GET_FLOAT_WORD(hx,x);
      38  	EXTRACT_WORDS(hy,ly,y);
      39  	ix = hx&0x7fffffff;		/* |x| */
      40  	iy = hy&0x7fffffff;		/* |y| */
      41  
      42  	if((ix>0x7f800000) ||				   /* x is nan */
      43  	   ((iy>=0x7ff00000)&&((iy-0x7ff00000)|ly)!=0))    /* y is nan */
      44  	   return x+y;
      45  	if((double) x==y) return y;		/* x=y, return y */
      46  	if(ix==0) {				/* x == 0 */
      47  	    float u;
      48  	    SET_FLOAT_WORD(x,(uint32_t)(hy&0x80000000)|1);/* return +-minsub*/
      49  	    u = math_opt_barrier (x);
      50  	    u = u * u;
      51  	    math_force_eval (u);		/* raise underflow flag */
      52  	    return x;
      53  	}
      54  	if(hx>=0) {				/* x > 0 */
      55  	    if(x > y)				/* x -= ulp */
      56  		hx -= 1;
      57  	    else				/* x < y, x += ulp */
      58  		hx += 1;
      59  	} else {				/* x < 0 */
      60  	    if(x < y)				/* x -= ulp */
      61  		hx -= 1;
      62  	    else				/* x > y, x += ulp */
      63  		hx += 1;
      64  	}
      65  	hy = hx&0x7f800000;
      66  	if(hy>=0x7f800000) {
      67  	  float u = x+x;			/* overflow  */
      68  	  math_force_eval (u);
      69  	  __set_errno (ERANGE);
      70  	}
      71  	if(hy<0x00800000) {
      72  	    float u = x*x;			/* underflow */
      73  	    math_force_eval (u);		/* raise underflow flag */
      74  	    __set_errno (ERANGE);
      75  	}
      76  	SET_FLOAT_WORD(x,hx);
      77  	return x;
      78  }
      79  
      80  #if LONG_DOUBLE_COMPAT(libm, GLIBC_2_1)
      81  compat_symbol (libm, __nldbl_nexttowardf, nexttowardf, GLIBC_2_1);
      82  #endif