1 /* @(#)s_modf.c 5.1 93/09/24 */
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 * ====================================================
12 * $FreeBSD: src/lib/msun/src/s_modf.c,v 1.5 1999/08/28 00:06:53 peter Exp $
13 * $DragonFly: src/lib/msun/src/Attic/s_modf.c,v 1.2 2003/06/17 04:26:53 dillon Exp $
17 * modf(double x, double *iptr)
18 * return fraction part of x, and return x's integral part in *iptr.
27 #include "math_private.h"
30 static const double one = 1.0;
32 static double one = 1.0;
36 double modf(double x, double *iptr)
44 EXTRACT_WORDS(i0,i1,x);
45 j0 = ((i0>>20)&0x7ff)-0x3ff; /* exponent of x */
46 if(j0<20) { /* integer part in high x */
47 if(j0<0) { /* |x|<1 */
48 INSERT_WORDS(*iptr,i0&0x80000000,0); /* *iptr = +-0 */
52 if(((i0&i)|i1)==0) { /* x is integral */
55 GET_HIGH_WORD(high,x);
56 INSERT_WORDS(x,high&0x80000000,0); /* return +-0 */
59 INSERT_WORDS(*iptr,i0&(~i),0);
63 } else if (j0>51) { /* no fraction part */
66 GET_HIGH_WORD(high,x);
67 INSERT_WORDS(x,high&0x80000000,0); /* return +-0 */
69 } else { /* fraction part in low x */
70 i = ((u_int32_t)(0xffffffff))>>(j0-20);
71 if((i1&i)==0) { /* x is integral */
74 GET_HIGH_WORD(high,x);
75 INSERT_WORDS(x,high&0x80000000,0); /* return +-0 */
78 INSERT_WORDS(*iptr,i0,i1&(~i));