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/*
16 * modfl(long double x, long double *iptr)
17 * return fraction part of x, and return x's integral part in *iptr.
18 * Method:
19 * Bit twiddling.
20 *
21 * Exception:
22 * No exception.
23 */
24
25#include <math.h>
26#include <math_private.h>
27#include <libm-alias-ldouble.h>
28
29static const long double one = 1.0;
30
31long double
32__modfl(long double x, long double *iptr)
33{
34 int32_t i0,i1,j0;
35 uint32_t i,se;
36 GET_LDOUBLE_WORDS(se,i0,i1,x);
37 j0 = (se&0x7fff)-0x3fff; /* exponent of x */
38 if(j0<32) { /* integer part in high x */
39 if(j0<0) { /* |x|<1 */
40 SET_LDOUBLE_WORDS(*iptr,se&0x8000,0,0); /* *iptr = +-0 */
41 return x;
42 } else {
43 i = (0x7fffffff)>>j0;
44 if(((i0&i)|i1)==0) { /* x is integral */
45 *iptr = x;
46 SET_LDOUBLE_WORDS(x,se&0x8000,0,0); /* return +-0 */
47 return x;
48 } else {
49 SET_LDOUBLE_WORDS(*iptr,se,i0&(~i),0);
50 return x - *iptr;
51 }
52 }
53 } else if (__builtin_expect(j0>63, 0)) { /* no fraction part */
54 *iptr = x*one;
55 /* We must handle NaNs separately. */
56 if (j0 == 0x4000 && ((i0 & 0x7fffffff) | i1))
57 return x*one;
58 SET_LDOUBLE_WORDS(x,se&0x8000,0,0); /* return +-0 */
59 return x;
60 } else { /* fraction part in low x */
61 i = ((uint32_t)(0x7fffffff))>>(j0-32);
62 if((i1&i)==0) { /* x is integral */
63 *iptr = x;
64 SET_LDOUBLE_WORDS(x,se&0x8000,0,0); /* return +-0 */
65 return x;
66 } else {
67 SET_LDOUBLE_WORDS(*iptr,se,i0,i1&(~i));
68 return x - *iptr;
69 }
70 }
71}
72libm_alias_ldouble (__modf, modf)
73