1  /* s_floorl.c -- long double version of s_floor.c.
       2   * Conversion to IEEE quad long double by Jakub Jelinek, jj@ultra.linux.cz.
       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  #if defined(LIBM_SCCS) && !defined(lint)
      17  static char rcsid[] = "$NetBSD: $";
      18  #endif
      19  
      20  /*
      21   * floorq(x)
      22   * Return x rounded toward -inf to integral value
      23   * Method:
      24   *	Bit twiddling.
      25   */
      26  
      27  #define NO_MATH_REDIRECT
      28  
      29  #include "quadmath-imp.h"
      30  
      31  __float128 floorq(__float128 x)
      32  {
      33  	int64_t i0,i1,j0;
      34  	uint64_t i,j;
      35  	GET_FLT128_WORDS64(i0,i1,x);
      36  	j0 = ((i0>>48)&0x7fff)-0x3fff;
      37  	if(j0<48) {
      38  	    if(j0<0) {
      39  		/* return 0*sign(x) if |x|<1 */
      40  		if(i0>=0) {i0=i1=0;}
      41  		else if(((i0&0x7fffffffffffffffLL)|i1)!=0)
      42  		    { i0=0xbfff000000000000ULL;i1=0;}
      43  	    } else {
      44  		i = (0x0000ffffffffffffULL)>>j0;
      45  		if(((i0&i)|i1)==0) return x; /* x is integral */
      46  		if(i0<0) i0 += (0x0001000000000000LL)>>j0;
      47  		i0 &= (~i); i1=0;
      48  	    }
      49  	} else if (j0>111) {
      50  	    if(j0==0x4000) return x+x;	/* inf or NaN */
      51  	    else return x;		/* x is integral */
      52  	} else {
      53  	    i = -1ULL>>(j0-48);
      54  	    if((i1&i)==0) return x;	/* x is integral */
      55  	    if(i0<0) {
      56  		if(j0==48) i0+=1;
      57  		else {
      58  		    j = i1+(1LL<<(112-j0));
      59  		    if(j<i1) i0 +=1 ; 	/* got a carry */
      60  		    i1=j;
      61  		}
      62  	    }
      63  	    i1 &= (~i);
      64  	}
      65  	SET_FLT128_WORDS64(x,i0,i1);
      66  	return x;
      67  }