1*627f7eb2Smrg /* s_modfl.c -- long double version of s_modf.c.
2*627f7eb2Smrg * Conversion to IEEE quad long double by Jakub Jelinek, jj@ultra.linux.cz.
3*627f7eb2Smrg */
4*627f7eb2Smrg
5*627f7eb2Smrg /*
6*627f7eb2Smrg * ====================================================
7*627f7eb2Smrg * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
8*627f7eb2Smrg *
9*627f7eb2Smrg * Developed at SunPro, a Sun Microsystems, Inc. business.
10*627f7eb2Smrg * Permission to use, copy, modify, and distribute this
11*627f7eb2Smrg * software is freely granted, provided that this notice
12*627f7eb2Smrg * is preserved.
13*627f7eb2Smrg * ====================================================
14*627f7eb2Smrg */
15*627f7eb2Smrg
16*627f7eb2Smrg #if defined(LIBM_SCCS) && !defined(lint)
17*627f7eb2Smrg static char rcsid[] = "NetBSD: ";
18*627f7eb2Smrg #endif
19*627f7eb2Smrg
20*627f7eb2Smrg /*
21*627f7eb2Smrg * modfq(long double x, long double *iptr)
22*627f7eb2Smrg * return fraction part of x, and return x's integral part in *iptr.
23*627f7eb2Smrg * Method:
24*627f7eb2Smrg * Bit twiddling.
25*627f7eb2Smrg *
26*627f7eb2Smrg * Exception:
27*627f7eb2Smrg * No exception.
28*627f7eb2Smrg */
29*627f7eb2Smrg
30*627f7eb2Smrg #include "quadmath-imp.h"
31*627f7eb2Smrg
32*627f7eb2Smrg static const __float128 one = 1.0;
33*627f7eb2Smrg
modfq(__float128 x,__float128 * iptr)34*627f7eb2Smrg __float128 modfq(__float128 x, __float128 *iptr)
35*627f7eb2Smrg {
36*627f7eb2Smrg int64_t i0,i1,j0;
37*627f7eb2Smrg uint64_t i;
38*627f7eb2Smrg GET_FLT128_WORDS64(i0,i1,x);
39*627f7eb2Smrg j0 = ((i0>>48)&0x7fff)-0x3fff; /* exponent of x */
40*627f7eb2Smrg if(j0<48) { /* integer part in high x */
41*627f7eb2Smrg if(j0<0) { /* |x|<1 */
42*627f7eb2Smrg /* *iptr = +-0 */
43*627f7eb2Smrg SET_FLT128_WORDS64(*iptr,i0&0x8000000000000000ULL,0);
44*627f7eb2Smrg return x;
45*627f7eb2Smrg } else {
46*627f7eb2Smrg i = (0x0000ffffffffffffLL)>>j0;
47*627f7eb2Smrg if(((i0&i)|i1)==0) { /* x is integral */
48*627f7eb2Smrg *iptr = x;
49*627f7eb2Smrg /* return +-0 */
50*627f7eb2Smrg SET_FLT128_WORDS64(x,i0&0x8000000000000000ULL,0);
51*627f7eb2Smrg return x;
52*627f7eb2Smrg } else {
53*627f7eb2Smrg SET_FLT128_WORDS64(*iptr,i0&(~i),0);
54*627f7eb2Smrg return x - *iptr;
55*627f7eb2Smrg }
56*627f7eb2Smrg }
57*627f7eb2Smrg } else if (j0>111) { /* no fraction part */
58*627f7eb2Smrg *iptr = x*one;
59*627f7eb2Smrg /* We must handle NaNs separately. */
60*627f7eb2Smrg if (j0 == 0x4000 && ((i0 & 0x0000ffffffffffffLL) | i1))
61*627f7eb2Smrg return x*one;
62*627f7eb2Smrg /* return +-0 */
63*627f7eb2Smrg SET_FLT128_WORDS64(x,i0&0x8000000000000000ULL,0);
64*627f7eb2Smrg return x;
65*627f7eb2Smrg } else { /* fraction part in low x */
66*627f7eb2Smrg i = -1ULL>>(j0-48);
67*627f7eb2Smrg if((i1&i)==0) { /* x is integral */
68*627f7eb2Smrg *iptr = x;
69*627f7eb2Smrg /* return +-0 */
70*627f7eb2Smrg SET_FLT128_WORDS64(x,i0&0x8000000000000000ULL,0);
71*627f7eb2Smrg return x;
72*627f7eb2Smrg } else {
73*627f7eb2Smrg SET_FLT128_WORDS64(*iptr,i0,i1&(~i));
74*627f7eb2Smrg return x - *iptr;
75*627f7eb2Smrg }
76*627f7eb2Smrg }
77*627f7eb2Smrg }
78