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