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      1  1.1  mrg /* s_modfl.c -- long double version of s_modf.c.
      2  1.1  mrg  * Conversion to IEEE quad long double by Jakub Jelinek, jj (at) ultra.linux.cz.
      3  1.1  mrg  */
      4  1.1  mrg 
      5  1.1  mrg /*
      6  1.1  mrg  * ====================================================
      7  1.1  mrg  * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
      8  1.1  mrg  *
      9  1.1  mrg  * Developed at SunPro, a Sun Microsystems, Inc. business.
     10  1.1  mrg  * Permission to use, copy, modify, and distribute this
     11  1.1  mrg  * software is freely granted, provided that this notice
     12  1.1  mrg  * is preserved.
     13  1.1  mrg  * ====================================================
     14  1.1  mrg  */
     15  1.1  mrg 
     16  1.1  mrg #if defined(LIBM_SCCS) && !defined(lint)
     17  1.1  mrg static char rcsid[] = "NetBSD: ";
     18  1.1  mrg #endif
     19  1.1  mrg 
     20  1.1  mrg /*
     21  1.1  mrg  * modfq(long double x, long double *iptr)
     22  1.1  mrg  * return fraction part of x, and return x's integral part in *iptr.
     23  1.1  mrg  * Method:
     24  1.1  mrg  *	Bit twiddling.
     25  1.1  mrg  *
     26  1.1  mrg  * Exception:
     27  1.1  mrg  *	No exception.
     28  1.1  mrg  */
     29  1.1  mrg 
     30  1.1  mrg #include "quadmath-imp.h"
     31  1.1  mrg 
     32  1.1  mrg static const __float128 one = 1.0;
     33  1.1  mrg 
     34  1.1  mrg __float128 modfq(__float128 x, __float128 *iptr)
     35  1.1  mrg {
     36  1.1  mrg 	int64_t i0,i1,j0;
     37  1.1  mrg 	uint64_t i;
     38  1.1  mrg 	GET_FLT128_WORDS64(i0,i1,x);
     39  1.1  mrg 	j0 = ((i0>>48)&0x7fff)-0x3fff;	/* exponent of x */
     40  1.1  mrg 	if(j0<48) {			/* integer part in high x */
     41  1.1  mrg 	    if(j0<0) {			/* |x|<1 */
     42  1.1  mrg 		/* *iptr = +-0 */
     43  1.1  mrg 	        SET_FLT128_WORDS64(*iptr,i0&0x8000000000000000ULL,0);
     44  1.1  mrg 		return x;
     45  1.1  mrg 	    } else {
     46  1.1  mrg 		i = (0x0000ffffffffffffLL)>>j0;
     47  1.1  mrg 		if(((i0&i)|i1)==0) {		/* x is integral */
     48  1.1  mrg 		    *iptr = x;
     49  1.1  mrg 		    /* return +-0 */
     50  1.1  mrg 		    SET_FLT128_WORDS64(x,i0&0x8000000000000000ULL,0);
     51  1.1  mrg 		    return x;
     52  1.1  mrg 		} else {
     53  1.1  mrg 		    SET_FLT128_WORDS64(*iptr,i0&(~i),0);
     54  1.1  mrg 		    return x - *iptr;
     55  1.1  mrg 		}
     56  1.1  mrg 	    }
     57  1.1  mrg 	} else if (j0>111) {		/* no fraction part */
     58  1.1  mrg 	    *iptr = x*one;
     59  1.1  mrg 	    /* We must handle NaNs separately.  */
     60  1.1  mrg 	    if (j0 == 0x4000 && ((i0 & 0x0000ffffffffffffLL) | i1))
     61  1.1  mrg 	      return x*one;
     62  1.1  mrg 	    /* return +-0 */
     63  1.1  mrg 	    SET_FLT128_WORDS64(x,i0&0x8000000000000000ULL,0);
     64  1.1  mrg 	    return x;
     65  1.1  mrg 	} else {			/* fraction part in low x */
     66  1.1  mrg 	    i = -1ULL>>(j0-48);
     67  1.1  mrg 	    if((i1&i)==0) { 		/* x is integral */
     68  1.1  mrg 		*iptr = x;
     69  1.1  mrg 		/* return +-0 */
     70  1.1  mrg 		SET_FLT128_WORDS64(x,i0&0x8000000000000000ULL,0);
     71  1.1  mrg 		return x;
     72  1.1  mrg 	    } else {
     73  1.1  mrg 		SET_FLT128_WORDS64(*iptr,i0,i1&(~i));
     74  1.1  mrg 		return x - *iptr;
     75  1.1  mrg 	    }
     76  1.1  mrg 	}
     77  1.1  mrg }
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