1*49393c00Smartynas /* @(#)s_modf.c 5.1 93/09/24 */
2*49393c00Smartynas /*
3*49393c00Smartynas * ====================================================
4*49393c00Smartynas * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
5*49393c00Smartynas *
6*49393c00Smartynas * Developed at SunPro, a Sun Microsystems, Inc. business.
7*49393c00Smartynas * Permission to use, copy, modify, and distribute this
8*49393c00Smartynas * software is freely granted, provided that this notice
9*49393c00Smartynas * is preserved.
10*49393c00Smartynas * ====================================================
11*49393c00Smartynas */
12*49393c00Smartynas
13*49393c00Smartynas /*
14*49393c00Smartynas * modfl(long double x, long double *iptr)
15*49393c00Smartynas * return fraction part of x, and return x's integral part in *iptr.
16*49393c00Smartynas * Method:
17*49393c00Smartynas * Bit twiddling.
18*49393c00Smartynas *
19*49393c00Smartynas * Exception:
20*49393c00Smartynas * No exception.
21*49393c00Smartynas */
22*49393c00Smartynas
23*49393c00Smartynas #include <math.h>
24*49393c00Smartynas
25*49393c00Smartynas #include "math_private.h"
26*49393c00Smartynas
27*49393c00Smartynas static const long double one = 1.0;
28*49393c00Smartynas
29*49393c00Smartynas long double
modfl(long double x,long double * iptr)30*49393c00Smartynas modfl(long double x, long double *iptr)
31*49393c00Smartynas {
32*49393c00Smartynas int32_t i0,i1,jj0;
33*49393c00Smartynas u_int32_t i,se;
34*49393c00Smartynas GET_LDOUBLE_WORDS(se,i0,i1,x);
35*49393c00Smartynas jj0 = (se&0x7fff)-0x3fff; /* exponent of x */
36*49393c00Smartynas if(jj0<32) { /* integer part in high x */
37*49393c00Smartynas if(jj0<0) { /* |x|<1 */
38*49393c00Smartynas SET_LDOUBLE_WORDS(*iptr,se&0x8000,0,0); /* *iptr = +-0 */
39*49393c00Smartynas return x;
40*49393c00Smartynas } else {
41*49393c00Smartynas i = (0x7fffffff)>>jj0;
42*49393c00Smartynas if(((i0&i)|i1)==0) { /* x is integral */
43*49393c00Smartynas *iptr = x;
44*49393c00Smartynas SET_LDOUBLE_WORDS(x,se&0x8000,0,0); /* return +-0 */
45*49393c00Smartynas return x;
46*49393c00Smartynas } else {
47*49393c00Smartynas SET_LDOUBLE_WORDS(*iptr,se,i0&(~i),0);
48*49393c00Smartynas return x - *iptr;
49*49393c00Smartynas }
50*49393c00Smartynas }
51*49393c00Smartynas } else if (jj0>63) { /* no fraction part */
52*49393c00Smartynas *iptr = x*one;
53*49393c00Smartynas /* We must handle NaNs separately. */
54*49393c00Smartynas if (jj0 == 0x4000 && ((i0 & 0x7fffffff) | i1))
55*49393c00Smartynas return x*one;
56*49393c00Smartynas SET_LDOUBLE_WORDS(x,se&0x8000,0,0); /* return +-0 */
57*49393c00Smartynas return x;
58*49393c00Smartynas } else { /* fraction part in low x */
59*49393c00Smartynas i = ((u_int32_t)(0x7fffffff))>>(jj0-32);
60*49393c00Smartynas if((i1&i)==0) { /* x is integral */
61*49393c00Smartynas *iptr = x;
62*49393c00Smartynas SET_LDOUBLE_WORDS(x,se&0x8000,0,0); /* return +-0 */
63*49393c00Smartynas return x;
64*49393c00Smartynas } else {
65*49393c00Smartynas SET_LDOUBLE_WORDS(*iptr,se,i0,i1&(~i));
66*49393c00Smartynas return x - *iptr;
67*49393c00Smartynas }
68*49393c00Smartynas }
69*49393c00Smartynas }
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