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comparison libquadmath/math/nearbyintq.c @ 68:561a7518be6b

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update gcc-4.6
author Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
date Sun, 21 Aug 2011 07:07:55 +0900
parents
children 04ced10e8804
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67:f6334be47118 68:561a7518be6b
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
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 i,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<48) {
53 if(j0<0) {
54 if(((i0&0x7fffffffffffffffLL)|i1)==0) return x;
55 i1 |= (i0&0x0000ffffffffffffLL);
56 i0 &= 0xffffe00000000000ULL;
57 i0 |= ((i1|-i1)>>16)&0x0000800000000000LL;
58 SET_FLT128_MSW64(x,i0);
59 #ifdef USE_FENV_H
60 feholdexcept (&env);
61 #endif
62 w = TWO112[sx]+x;
63 t = w-TWO112[sx];
64 #ifdef USE_FENV_H
65 fesetenv (&env);
66 #endif
67 GET_FLT128_MSW64(i0,t);
68 SET_FLT128_MSW64(t,(i0&0x7fffffffffffffffLL)|(sx<<63));
69 return t;
70 } else {
71 i = (0x0000ffffffffffffLL)>>j0;
72 if(((i0&i)|i1)==0) return x; /* x is integral */
73 i>>=1;
74 if(((i0&i)|i1)!=0) {
75 if(j0==47) i1 = 0x4000000000000000ULL; else
76 i0 = (i0&(~i))|((0x0000200000000000LL)>>j0);
77 }
78 }
79 } else if (j0>111) {
80 if(j0==0x4000) return x+x; /* inf or NaN */
81 else return x; /* x is integral */
82 } else {
83 i = -1ULL>>(j0-48);
84 if((i1&i)==0) return x; /* x is integral */
85 i>>=1;
86 if((i1&i)!=0) i1 = (i1&(~i))|((0x4000000000000000LL)>>(j0-48));
87 }
88 SET_FLT128_WORDS64(x,i0,i1);
89 #ifdef USE_FENV_H
90 feholdexcept (&env);
91 #endif
92 w = TWO112[sx]+x;
93 t = w-TWO112[sx];
94 #ifdef USE_FENV_H
95 fesetenv (&env);
96 #endif
97 return t;
98 }