1/* s_modfl.c -- long double version of s_modf.c.
2 */
3
4/*
5 * ====================================================
6 * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
7 *
8 * Developed at SunPro, a Sun Microsystems, Inc. business.
9 * Permission to use, copy, modify, and distribute this
10 * software is freely granted, provided that this notice
11 * is preserved.
12 * ====================================================
13 */
14
15#if defined(LIBM_SCCS) && !defined(lint)
16static char rcsid[] = "$NetBSD: $";
17#endif
18
19/*
20 * modfl(long double x, long double *iptr)
21 * return fraction part of x, and return x's integral part in *iptr.
22 * Method:
23 * Bit twiddling.
24 *
25 * Exception:
26 * No exception.
27 */
28
29#include <math.h>
30#include <math_private.h>
31#include <libm-alias-ldouble.h>
32
33static const _Float128 one = 1.0;
34
35_Float128 __modfl(_Float128 x, _Float128 *iptr)
36{
37 int64_t i0,i1,j0;
38 uint64_t i;
39 GET_LDOUBLE_WORDS64(i0,i1,x);
40 j0 = ((i0>>48)&0x7fff)-0x3fff; /* exponent of x */
41 if(j0<48) { /* integer part in high x */
42 if(j0<0) { /* |x|<1 */
43 /* *iptr = +-0 */
44 SET_LDOUBLE_WORDS64(*iptr,i0&0x8000000000000000ULL,0);
45 return x;
46 } else {
47 i = (0x0000ffffffffffffLL)>>j0;
48 if(((i0&i)|i1)==0) { /* x is integral */
49 *iptr = x;
50 /* return +-0 */
51 SET_LDOUBLE_WORDS64(x,i0&0x8000000000000000ULL,0);
52 return x;
53 } else {
54 SET_LDOUBLE_WORDS64(*iptr,i0&(~i),0);
55 return x - *iptr;
56 }
57 }
58 } else if (j0>111) { /* no fraction part */
59 *iptr = x*one;
60 /* We must handle NaNs separately. */
61 if (j0 == 0x4000 && ((i0 & 0x0000ffffffffffffLL) | i1))
62 return x*one;
63 /* return +-0 */
64 SET_LDOUBLE_WORDS64(x,i0&0x8000000000000000ULL,0);
65 return x;
66 } else { /* fraction part in low x */
67 i = -1ULL>>(j0-48);
68 if((i1&i)==0) { /* x is integral */
69 *iptr = x;
70 /* return +-0 */
71 SET_LDOUBLE_WORDS64(x,i0&0x8000000000000000ULL,0);
72 return x;
73 } else {
74 SET_LDOUBLE_WORDS64(*iptr,i0,i1&(~i));
75 return x - *iptr;
76 }
77 }
78}
79libm_alias_ldouble (__modf, modf)
80