blob: c80ae66a0f1865bd71de9742c427670448dff238 (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
|
/*
* June 19, 2001 Manuel Novoa III
*
* Replaced cephes round (which was actually round to nearest or even)
* with a (really lame actually) version that always rounds away from 0
* in conformance with ANSI/ISO.
*
* This doesn't check for inf or nan (hence the lame part) but the
* cephes function it replaces didn't either. I plan to deal with
* those issues when I rework things w.r.t. common code.
*
* Also, for now rename the original cephes round routine to rint since
* it behaves the same for the default rounding mode (round to nearest).
* This will have to be changed off course when floating point env
* control functions are added.
*/
#include <math.h>
double round(x)
double x;
{
double ax, fax;
ax = fabs(x);
fax = floor(ax);
if (ax - fax >= 0.5) {
fax += 1.0;
}
if (x < 0) {
x = -fax;
} else {
x = fax;
}
return x;
}
/***********************************************************************/
/*
* Returns the nearest integer to x as a double precision
* floating point result. If x ends in 0.5 exactly, the
* nearest even integer is chosen.
* /
/*
Originally round from
Cephes Math Library Release 2.1: January, 1989
Copyright 1984, 1987, 1989 by Stephen L. Moshier
Direct inquiries to 30 Frost Street, Cambridge, MA 02140
*/
double rint(x)
double x;
{
double y, r;
/* Largest integer <= x */
y = floor(x);
/* Fractional part */
r = x - y;
/* Round up to nearest. */
if( r > 0.5 )
goto rndup;
/* Round to even */
if( r == 0.5 )
{
r = y - 2.0 * floor( 0.5 * y );
if( r == 1.0 )
{
rndup:
y += 1.0;
}
}
/* Else round down. */
return(y);
}
|
