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 double modf(double x, double *iptr)
29 EXTRACT_WORDS(i0, i1, x);
30 j0 = ((i0>>20) & 0x7ff) - 0x3ff; /* exponent of x */
31 if (j0 < 20) { /* integer part in high x */
32 if (j0 < 0) { /* |x| < 1 */
33 INSERT_WORDS(*iptr, i0 & 0x80000000, 0); /* *iptr = +-0 */
37 if (((i0&i)|i1) == 0) { /* x is integral */
40 GET_HIGH_WORD(high, x);
41 INSERT_WORDS(x, high & 0x80000000, 0); /* return +-0 */
44 INSERT_WORDS(*iptr, i0&~i, 0);
46 } else if (j0 > 51) { /* no fraction part */
48 if (j0 == 0x400) { /* inf/NaN */
53 GET_HIGH_WORD(high, x);
54 INSERT_WORDS(x, high & 0x80000000, 0); /* return +-0 */
56 } else { /* fraction part in low x */
57 i = (uint32_t)0xffffffff >> (j0 - 20);
58 if ((i1&i) == 0) { /* x is integral */
61 GET_HIGH_WORD(high, x);
62 INSERT_WORDS(x, high & 0x80000000, 0); /* return +-0 */
65 INSERT_WORDS(*iptr, i0, i1&~i);