1 /* @(#)s_rint.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 * ====================================================
15 * Return x rounded to integral value according to the prevailing
18 * Using floating addition.
20 * Inexact flag raised if x not equal to rint(x).
24 #include "math_private.h"
27 * TWO23 is long double instead of double to avoid a bug in gcc. Without
28 * this, gcc thinks that TWO23[sx]+x and w-TWO23[sx] already have double
29 * precision and doesn't clip them to double precision when they are
30 * assigned and returned.
32 static const long double
34 4.50359962737049600000e+15, /* 0x43300000, 0x00000000 */
35 -4.50359962737049600000e+15, /* 0xC3300000, 0x00000000 */
44 EXTRACT_WORDS(i0,i1,x);
46 j0 = ((i0>>20)&0x7ff)-0x3ff;
49 if(((i0&0x7fffffff)|i1)==0) return x;
52 i0 |= ((i1|-i1)>>12)&0x80000;
57 SET_HIGH_WORD(t,(i0&0x7fffffff)|(sx<<31));
61 if(((i0&i)|i1)==0) return x; /* x is integral */
64 if(j0==19) i1 = 0x40000000; else
65 i0 = (i0&(~i))|((0x20000)>>j0);
69 if(j0==0x400) return x+x; /* inf or NaN */
70 else return x; /* x is integral */
72 i = ((uint32_t)(0xffffffff))>>(j0-20);
73 if((i1&i)==0) return x; /* x is integral */
75 if((i1&i)!=0) i1 = (i1&(~i))|((0x40000000)>>(j0-20));
77 INSERT_WORDS(x,i0,i1);