URL https://opencores.org/ocsvn/openrisc/openrisc/trunk

Subversion Repositories openrisc

[/] [openrisc/] [trunk/] [gnu-stable/] [newlib-1.18.0/] [newlib/] [libm/] [common/] [s_rint.c] - Blame information for rev 859

Go to most recent revision | Details | Compare with Previous | View Log


 
/* @(#)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.
 * ====================================================
 */
/*
FUNCTION
<<rint>>, <<rintf>>--round to integer
INDEX
        rint
INDEX
        rintf
 
ANSI_SYNOPSIS
        #include <math.h>
        double rint(double <[x]>);
        float rintf(float <[x]>);
 
DESCRIPTION
        The <<rint>> functions round their argument to an integer value in
        floating-point format, using the current rounding direction.  They
        raise the "inexact" floating-point exception if the result differs
        in value from the argument.  See the <<nearbyint>> functions for the
        same function with the "inexact" floating-point exception never being
        raised.  Newlib does not directly support floating-point exceptions.
        The <<rint>> functions are written so that the "inexact" exception is
        raised in hardware implementations that support it, even though Newlib
        does not provide access.
 
RETURNS
<[x]> rounded to an integral value, using the current rounding direction.
 
PORTABILITY
ANSI C, POSIX
 
SEEALSO
<<nearbyint>>, <<round>>
 
*/
 
/*
 * 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	207	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			`FUNCTION`
15			`<<rint>>, <<rintf>>--round to integer`
16			`INDEX`
17			`rint`
18			`INDEX`
19			`rintf`
20
21			`ANSI_SYNOPSIS`
22			`#include <math.h>`
23			`double rint(double <[x]>);`
24			`float rintf(float <[x]>);`
25
26			`DESCRIPTION`
27			`The <<rint>> functions round their argument to an integer value in`
28			`floating-point format, using the current rounding direction. They`
29			`raise the "inexact" floating-point exception if the result differs`
30			`in value from the argument. See the <<nearbyint>> functions for the`
31			`same function with the "inexact" floating-point exception never being`
32			`raised. Newlib does not directly support floating-point exceptions.`
33			`The <<rint>> functions are written so that the "inexact" exception is`
34			`raised in hardware implementations that support it, even though Newlib`
35			`does not provide access.`
36
37			`RETURNS`
38			`<[x]> rounded to an integral value, using the current rounding direction.`
39
40			`PORTABILITY`
41			`ANSI C, POSIX`
42
43			`SEEALSO`
44			`<<nearbyint>>, <<round>>`
45
46			`*/`
47
48			`/*`
49			`* rint(x)`
50			`* Return x rounded to integral value according to the prevailing`
51			`* rounding mode.`
52			`* Method:`
53			`* Using floating addition.`
54			`* Exception:`
55			`* Inexact flag raised if x not equal to rint(x).`
56			`*/`
57
58			`#include "fdlibm.h"`
59
60			`#ifndef _DOUBLE_IS_32BITS`
61
62			`#ifdef __STDC__`
63			`static const double`
64			`#else`
65			`static double`
66			`#endif`
67			`TWO52[2]={`
68			`4.50359962737049600000e+15, /* 0x43300000, 0x00000000 */`
69			`-4.50359962737049600000e+15, /* 0xC3300000, 0x00000000 */`
70			`};`
71
72			`#ifdef __STDC__`
73			`double rint(double x)`
74			`#else`
75			`double rint(x)`
76			`double x;`
77			`#endif`
78			`{`
79			`__int32_t i0,j0,sx;`
80			`__uint32_t i,i1;`
81			`double t;`
82			`volatile double w;`
83			`EXTRACT_WORDS(i0,i1,x);`
84			`sx = (i0>>31)&1;`
85			`j0 = ((i0>>20)&0x7ff)-0x3ff;`
86			`if(j0<20) {`
87			`if(j0<0) {`
88			`if(((i0&0x7fffffff)\|i1)==0) return x;`
89			`i1 \|= (i0&0x0fffff);`
90			`i0 &= 0xfffe0000;`
91			`i0 \|= ((i1\|-i1)>>12)&0x80000;`
92			`SET_HIGH_WORD(x,i0);`
93			`w = TWO52[sx]+x;`
94			`t = w-TWO52[sx];`
95			`GET_HIGH_WORD(i0,t);`
96			`SET_HIGH_WORD(t,(i0&0x7fffffff)\|(sx<<31));`
97			`return t;`
98			`} else {`
99			`i = (0x000fffff)>>j0;`
100			`if(((i0&i)\|i1)==0) return x; /* x is integral */`
101			`i>>=1;`
102			`if(((i0&i)\|i1)!=0) {`
103			`if(j0==19) i1 = 0x40000000; else`
104			`i0 = (i0&(~i))\|((0x20000)>>j0);`
105			`}`
106			`}`
107			`} else if (j0>51) {`
108			`if(j0==0x400) return x+x; /* inf or NaN */`
109			`else return x; /* x is integral */`
110			`} else {`
111			`i = ((__uint32_t)(0xffffffff))>>(j0-20);`
112			`if((i1&i)==0) return x; /* x is integral */`
113			`i>>=1;`
114			`if((i1&i)!=0) i1 = (i1&(~i))\|((0x40000000)>>(j0-20));`
115			`}`
116			`INSERT_WORDS(x,i0,i1);`
117			`w = TWO52[sx]+x;`
118			`return w-TWO52[sx];`
119			`}`
120
121			`#endif /* _DOUBLE_IS_32BITS */`
122
123
124

Browse

Tools

Subversion Repositories openrisc

[/] [openrisc/] [trunk/] [gnu-stable/] [newlib-1.18.0/] [newlib/] [libm/] [common/] [s_rint.c] - Blame information for rev 859