1 /* origin: FreeBSD /usr/src/lib/msun/src/s_modf.c */
3 * ====================================================
4 * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
6 * Developed at SunPro, a Sun Microsystems, Inc. business.
7 * Permission to use, copy, modify, and distribute this
8 * software is freely granted, provided that this notice
10 * ====================================================
13 * modf(double x, double *iptr)
14 * return fraction part of x, and return x's integral part in *iptr.
24 static const double one = 1.0;
26 double modf(double x, double *iptr)
31 EXTRACT_WORDS(i0, i1, x);
32 j0 = ((i0>>20) & 0x7ff) - 0x3ff; /* exponent of x */
33 if (j0 < 20) { /* integer part in high x */
34 if (j0 < 0) { /* |x| < 1 */
35 INSERT_WORDS(*iptr, i0 & 0x80000000, 0); /* *iptr = +-0 */
39 if (((i0&i)|i1) == 0) { /* x is integral */
42 GET_HIGH_WORD(high, x);
43 INSERT_WORDS(x, high & 0x80000000, 0); /* return +-0 */
46 INSERT_WORDS(*iptr, i0&~i, 0);
48 } else if (j0 > 51) { /* no fraction part */
50 if (j0 == 0x400) { /* inf/NaN */
55 GET_HIGH_WORD(high, x);
56 INSERT_WORDS(x, high & 0x80000000, 0); /* return +-0 */
58 } else { /* fraction part in low x */
59 i = (uint32_t)0xffffffff >> (j0 - 20);
60 if ((i1&i) == 0) { /* x is integral */
63 GET_HIGH_WORD(high, x);
64 INSERT_WORDS(x, high & 0x80000000, 0); /* return +-0 */
67 INSERT_WORDS(*iptr, i0, i1&~i);