1 /* nearbyintq.c -- __float128 version of s_nearbyint.c.
2 * Conversion to IEEE quad long double by Jakub Jelinek, jj@ultra.linux.cz.
3 */
4
5 /*
6 * ====================================================
7 * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
8 *
9 * Developed at SunPro, a Sun Microsystems, Inc. business.
10 * Permission to use, copy, modify, and distribute this
11 * software is freely granted, provided that this notice
12 * is preserved.
13 * ====================================================
14 */
15
16 /*
17 * nearbyintq(x)
18 * Return x rounded to integral value according to the prevailing
19 * rounding mode.
20 * Method:
21 * Using floating addition.
22 * Exception:
23 * Inexact flag raised if x not equal to rintq(x).
24 */
25
26 #include "quadmath-imp.h"
27 #ifdef HAVE_FENV_H
28 # include <fenv.h>
29 # if defined HAVE_FEHOLDEXCEPT && defined HAVE_FESETENV
30 # define USE_FENV_H
31 # endif
32 #endif
33
34 static const __float128
35 TWO112[2]={
36 5.19229685853482762853049632922009600E+33Q, /* 0x406F000000000000, 0 */
37 -5.19229685853482762853049632922009600E+33Q /* 0xC06F000000000000, 0 */
38 };
39
40 __float128
nearbyintq(__float128 x)41 nearbyintq(__float128 x)
42 {
43 #ifdef USE_FENV_H
44 fenv_t env;
45 #endif
46 int64_t i0,j0,sx;
47 uint64_t i1;
48 __float128 w,t;
49 GET_FLT128_WORDS64(i0,i1,x);
50 sx = (((uint64_t)i0)>>63);
51 j0 = ((i0>>48)&0x7fff)-0x3fff;
52 if(j0<112) {
53 if(j0<0) {
54 #ifdef USE_FENV_H
55 feholdexcept (&env);
56 #endif
57 w = TWO112[sx]+x;
58 t = w-TWO112[sx];
59 #ifdef USE_FENV_H
60 fesetenv (&env);
61 #endif
62 GET_FLT128_MSW64(i0,t);
63 SET_FLT128_MSW64(t,(i0&0x7fffffffffffffffLL)|(sx<<63));
64 return t;
65 }
66 } else {
67 if(j0==0x4000) return x+x; /* inf or NaN */
68 else return x; /* x is integral */
69 }
70 #ifdef USE_FENV_H
71 feholdexcept (&env);
72 #endif
73 w = TWO112[sx]+x;
74 t = w-TWO112[sx];
75 #ifdef USE_FENV_H
76 fesetenv (&env);
77 #endif
78 return t;
79 }
80