blob: 2bcfc8638e5ef173c35eec2d89585792f4d85118 (
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
|
#include <math.h>
typedef union
{
long double value;
struct
{
unsigned mantissa[2];
unsigned sign_exponent : 16;
unsigned empty : 16;
} parts;
} ieee_long_double_shape_type;
/* Get int from the exponent of a long double. */
static __inline__ void
get_ld_exp (unsigned exp,long double d)
{
ieee_long_double_shape_type u;
u.value = d;
exp = u.parts.sign_exponent;
}
/* Set exponent of a long double from an int. */
static __inline__ void
set_ld_exp (long double d,unsigned exp)
{
ieee_long_double_shape_type u;
u.value = d;
u.parts.sign_exponent = exp;
d = u.value;
}
long double
hypotl (long double x, long double y)
{
unsigned exx = 0U;
unsigned eyy = 0U;
unsigned scale;
long double xx =fabsl(x);
long double yy =fabsl(y);
if (!isfinite(xx) || !isfinite(yy))
return xx + yy; /* Return INF or NAN. */
/* Scale to avoid overflow.*/
get_ld_exp (exx, xx);
get_ld_exp (eyy, yy);
scale = (exx > eyy ? exx : eyy);
if (scale == 0)
return 0.0L;
set_ld_exp (xx, exx - scale);
set_ld_exp (yy, eyy - scale);
xx = sqrtl(xx * xx + yy * yy);
get_ld_exp (exx,xx);
set_ld_exp (xx, exx + scale);
return xx;
}
|
