(__ieee754_sqrt): Remove unused variables b and n.
[kopensolaris-gnu/glibc.git] / sysdeps / ieee754 / ldbl-96 / s_nearbyintl.c
1 /* s_rintl.c -- long double version of s_rint.c.
2  * Conversion to long double by Ulrich Drepper,
3  * Cygnus Support, drepper@cygnus.com.
4  */
5 /* Adapted for use as nearbyint by Ulrich Drepper <drepper@cygnus.com>.  */
6
7 /*
8  * ====================================================
9  * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
10  *
11  * Developed at SunPro, a Sun Microsystems, Inc. business.
12  * Permission to use, copy, modify, and distribute this
13  * software is freely granted, provided that this notice
14  * is preserved.
15  * ====================================================
16  */
17
18 /*
19  * rintl(x)
20  * Return x rounded to integral value according to the prevailing
21  * rounding mode.
22  * Method:
23  *      Using floating addition.
24  * Exception:
25  *      Inexact flag raised if x not equal to rintl(x).
26  */
27
28 #include <fenv.h>
29 #include "math.h"
30 #include "math_private.h"
31
32 #ifdef __STDC__
33 static const long double
34 #else
35 static long double
36 #endif
37 TWO63[2]={
38   9.223372036854775808000000e+18, /* 0x403E, 0x00000000, 0x00000000 */
39  -9.223372036854775808000000e+18  /* 0xC03E, 0x00000000, 0x00000000 */
40 };
41
42 #ifdef __STDC__
43         long double __nearbyintl(long double x)
44 #else
45         long double __nearbyintl(x)
46         long double x;
47 #endif
48 {
49         fenv_t env;
50         int32_t se,j0,sx;
51         u_int32_t i,i0,i1;
52         long double w,t;
53         GET_LDOUBLE_WORDS(se,i0,i1,x);
54         sx = (se>>15)&1;
55         j0 = (se&0x7fff)-0x3fff;
56         if(j0<31) {
57             if(j0<0) {
58                 if(((se&0x7fff)|i0|i1)==0) return x;
59                 i1 |= i0;
60                 i0 &= 0xe0000000;
61                 i0 |= (i1|-i1)&0x80000000;
62                 SET_LDOUBLE_MSW(x,i0);
63                 feholdexcept (&env);
64                 w = TWO63[sx]+x;
65                 t = w-TWO63[sx];
66                 fesetenv (&env);
67                 GET_LDOUBLE_EXP(i0,t);
68                 SET_LDOUBLE_EXP(t,(i0&0x7fff)|(sx<<15));
69                 return t;
70             } else {
71                 i = (0x7fffffff)>>j0;
72                 if(((i0&i)|i1)==0) return x; /* x is integral */
73                 i>>=1;
74                 if(((i0&i)|i1)!=0) {
75                     if (j0==30) i1 = 0x40000000; else
76                     i0 = (i0&(~i))|((0x20000000)>>j0);
77                 }
78             }
79         } else if (j0>62) {
80             if(j0==0x4000) return x+x;  /* inf or NaN */
81             else return x;              /* x is integral */
82         } else {
83             i = ((u_int32_t)(0xffffffff))>>(j0-31);
84             if((i1&i)==0) return x;     /* x is integral */
85             i>>=1;
86             if((i1&i)!=0) i1 = (i1&(~i))|((0x40000000)>>(j0-31));
87         }
88         SET_LDOUBLE_WORDS(x,se,i0,i1);
89         feholdexcept (&env);
90         w = TWO63[sx]+x;
91         t = w-TWO63[sx];
92         fesetenv (&env);
93         return t;
94 }
95 weak_alias (__nearbyintl, nearbyintl)