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/* @(#)s_rint.c 5.1 93/09/24 */
/*
 * ====================================================
 * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
 *
 * Developed at SunPro, a Sun Microsystems, Inc. business.
 * Permission to use, copy, modify, and distribute this
 * software is freely granted, provided that this notice
 * is preserved.
 * ====================================================
 */
 
/*
 * rint(x)
 * Return x rounded to integral value according to the prevailing
 * rounding mode.
 * Method:
 *      Using floating addition.
 * Exception:
 *      Inexact flag raised if x not equal to rint(x).
 */
 
#include "fdlibm.h"
 
#ifndef _DOUBLE_IS_32BITS
 
#ifdef __STDC__
static const double
#else
static double
#endif
TWO52[2]={
  4.50359962737049600000e+15, /* 0x43300000, 0x00000000 */
 -4.50359962737049600000e+15, /* 0xC3300000, 0x00000000 */
};
 
#ifdef __STDC__
        double rint(double x)
#else
        double rint(x)
        double x;
#endif
{
        __int32_t i0,j0,sx;
        __uint32_t i,i1;
        double t;
        volatile double w;
        EXTRACT_WORDS(i0,i1,x);
        sx = (i0>>31)&1;
        j0 = ((i0>>20)&0x7ff)-0x3ff;
        if(j0<20) {
            if(j0<0) {
                if(((i0&0x7fffffff)|i1)==0) return x;
                i1 |= (i0&0x0fffff);
                i0 &= 0xfffe0000;
                i0 |= ((i1|-i1)>>12)&0x80000;
                SET_HIGH_WORD(x,i0);
                w = TWO52[sx]+x;
                t =  w-TWO52[sx];
                GET_HIGH_WORD(i0,t);
                SET_HIGH_WORD(t,(i0&0x7fffffff)|(sx<<31));
                return t;
            } else {
                i = (0x000fffff)>>j0;
                if(((i0&i)|i1)==0) return x; /* x is integral */
                i>>=1;
                if(((i0&i)|i1)!=0) {
                    if(j0==19) i1 = 0x40000000; else
                    i0 = (i0&(~i))|((0x20000)>>j0);
                }
            }
        } else if (j0>51) {
            if(j0==0x400) return x+x;   /* inf or NaN */
            else return x;              /* x is integral */
        } else {
            i = ((__uint32_t)(0xffffffff))>>(j0-20);
            if((i1&i)==0) return x;      /* x is integral */
            i>>=1;
            if((i1&i)!=0) i1 = (i1&(~i))|((0x40000000)>>(j0-20));
        }
        INSERT_WORDS(x,i0,i1);
        w = TWO52[sx]+x;
        return w-TWO52[sx];
}
 
#endif /* _DOUBLE_IS_32BITS */
 
 
 

Line No.	Rev	Author	Line
1	148	jeremybenn
2			`/* @(#)s_rint.c 5.1 93/09/24 */`
3			`/*`
4			`* ====================================================`
5			`* Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.`
6			`*`
7			`* Developed at SunPro, a Sun Microsystems, Inc. business.`
8			`* Permission to use, copy, modify, and distribute this`
9			`* software is freely granted, provided that this notice`
10			`* is preserved.`
11			`* ====================================================`
12			`*/`
13
14			`/*`
15			`* rint(x)`
16			`* Return x rounded to integral value according to the prevailing`
17			`* rounding mode.`
18			`* Method:`
19			`* Using floating addition.`
20			`* Exception:`
21			`* Inexact flag raised if x not equal to rint(x).`
22			`*/`
23
24			`#include "fdlibm.h"`
25
26			`#ifndef _DOUBLE_IS_32BITS`
27
28			`#ifdef __STDC__`
29			`static const double`
30			`#else`
31			`static double`
32			`#endif`
33			`TWO52[2]={`
34			`4.50359962737049600000e+15, /* 0x43300000, 0x00000000 */`
35			`-4.50359962737049600000e+15, /* 0xC3300000, 0x00000000 */`
36			`};`
37
38			`#ifdef __STDC__`
39			`double rint(double x)`
40			`#else`
41			`double rint(x)`
42			`double x;`
43			`#endif`
44			`{`
45			`__int32_t i0,j0,sx;`
46			`__uint32_t i,i1;`
47			`double t;`
48			`volatile double w;`
49			`EXTRACT_WORDS(i0,i1,x);`
50			`sx = (i0>>31)&1;`
51			`j0 = ((i0>>20)&0x7ff)-0x3ff;`
52			`if(j0<20) {`
53			`if(j0<0) {`
54			`if(((i0&0x7fffffff)\|i1)==0) return x;`
55			`i1 \|= (i0&0x0fffff);`
56			`i0 &= 0xfffe0000;`
57			`i0 \|= ((i1\|-i1)>>12)&0x80000;`
58			`SET_HIGH_WORD(x,i0);`
59			`w = TWO52[sx]+x;`
60			`t = w-TWO52[sx];`
61			`GET_HIGH_WORD(i0,t);`
62			`SET_HIGH_WORD(t,(i0&0x7fffffff)\|(sx<<31));`
63			`return t;`
64			`} else {`
65			`i = (0x000fffff)>>j0;`
66			`if(((i0&i)\|i1)==0) return x; /* x is integral */`
67			`i>>=1;`
68			`if(((i0&i)\|i1)!=0) {`
69			`if(j0==19) i1 = 0x40000000; else`
70			`i0 = (i0&(~i))\|((0x20000)>>j0);`
71			`}`
72			`}`
73			`} else if (j0>51) {`
74			`if(j0==0x400) return x+x; /* inf or NaN */`
75			`else return x; /* x is integral */`
76			`} else {`
77			`i = ((__uint32_t)(0xffffffff))>>(j0-20);`
78			`if((i1&i)==0) return x; /* x is integral */`
79			`i>>=1;`
80			`if((i1&i)!=0) i1 = (i1&(~i))\|((0x40000000)>>(j0-20));`
81			`}`
82			`INSERT_WORDS(x,i0,i1);`
83			`w = TWO52[sx]+x;`
84			`return w-TWO52[sx];`
85			`}`
86
87			`#endif /* _DOUBLE_IS_32BITS */`
88
89
90

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[/] [openrisc/] [trunk/] [gnu-old/] [newlib-1.17.0/] [newlib/] [libm/] [common/] [s_rint.c] - Blame information for rev 822