1/* s_modfl.c -- long double version of s_modf.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)
17static char rcsid[] = "$NetBSD: $";
18#endif
19
20/*
21 * modfl(long double x, long double *iptr)
22 * return fraction part of x, and return x's integral part in *iptr.
23 * Method:
24 * Bit twiddling.
25 *
26 * Exception:
27 * No exception.
28 */
29
30#include <math.h>
31#include <math_private.h>
32#include <libm-alias-ldouble.h>
33
34static const _Float128 one = 1.0;
35
36_Float128 __modfl(_Float128 x, _Float128 *iptr)
37{
38 int64_t i0,i1,j0;
39 uint64_t i;
40 GET_LDOUBLE_WORDS64(i0,i1,x);
41 j0 = ((i0>>48)&0x7fff)-0x3fff; /* exponent of x */
42 if(j0<48) { /* integer part in high x */
43 if(j0<0) { /* |x|<1 */
44 /* *iptr = +-0 */
45 SET_LDOUBLE_WORDS64(*iptr,i0&0x8000000000000000ULL,0);
46 return x;
47 } else {
48 i = (0x0000ffffffffffffLL)>>j0;
49 if(((i0&i)|i1)==0) { /* x is integral */
50 *iptr = x;
51 /* return +-0 */
52 SET_LDOUBLE_WORDS64(x,i0&0x8000000000000000ULL,0);
53 return x;
54 } else {
55 SET_LDOUBLE_WORDS64(*iptr,i0&(~i),0);
56 return x - *iptr;
57 }
58 }
59 } else if (j0>111) { /* no fraction part */
60 *iptr = x*one;
61 /* We must handle NaNs separately. */
62 if (j0 == 0x4000 && ((i0 & 0x0000ffffffffffffLL) | i1))
63 return x*one;
64 /* return +-0 */
65 SET_LDOUBLE_WORDS64(x,i0&0x8000000000000000ULL,0);
66 return x;
67 } else { /* fraction part in low x */
68 i = -1ULL>>(j0-48);
69 if((i1&i)==0) { /* x is integral */
70 *iptr = x;
71 /* return +-0 */
72 SET_LDOUBLE_WORDS64(x,i0&0x8000000000000000ULL,0);
73 return x;
74 } else {
75 SET_LDOUBLE_WORDS64(*iptr,i0,i1&(~i));
76 return x - *iptr;
77 }
78 }
79}
80libm_alias_ldouble (__modf, modf)
81