blob: b306044c1f9769c0b48c3b7e8018012b5a4d5ab8 (
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
|
/* Public domain. */
typedef int DItype __attribute__ ((mode (DI)));
typedef unsigned int UDItype __attribute__ ((mode (DI)));
typedef int SItype __attribute__ ((mode (SI)));
typedef unsigned int USItype __attribute__ ((mode (SI)));
typedef float SFtype __attribute__ ((mode (SF)));
typedef float DFtype __attribute__ ((mode (DF)));
SFtype __floatdisf (DItype);
SFtype
__floatdisf (DItype u)
{
/* Protect against double-rounding error.
Represent any low-order bits, that might be truncated by a bit that
won't be lost. The bit can go in anywhere below the rounding position
of SFtype. A fixed mask and bit position handles all usual
configurations. */
if (53 < (sizeof (DItype) * 8)
&& 53 > ((sizeof (DItype) * 8) - 53 + 24))
{
if (!(- ((DItype) 1 << 53) < u
&& u < ((DItype) 1 << 53)))
{
if ((UDItype) u & (((UDItype) 1 << (sizeof (DItype) * 8 - 53)) - 1))
{
u &= ~ (((UDItype) 1 << (sizeof (DItype) * 8 - 53)) - 1);
u |= (UDItype) 1 << (sizeof (DItype) * 8 - 53);
}
}
}
/* Do the calculation in a wider type so that we don't lose any of
the precision of the high word while multiplying it. */
DFtype f = (SItype) (u >> (sizeof (SItype) * 8));
f *= 0x1p32f;
f += (USItype) u;
return (SFtype) f;
}
|
