aboutsummaryrefslogtreecommitdiffstats
path: root/contrib/libs/cxxsupp/builtins/fixunsxfsi.c
blob: c3c70f743de8fbf52651bfbfe66618e9f4efe1cf (plain) (blame)
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
/* ===-- fixunsxfsi.c - Implement __fixunsxfsi -----------------------------===
 *
 *                     The LLVM Compiler Infrastructure
 *
 * This file is dual licensed under the MIT and the University of Illinois Open
 * Source Licenses. See LICENSE.TXT for details.
 *
 * ===----------------------------------------------------------------------===
 *
 * This file implements __fixunsxfsi for the compiler_rt library.
 *
 * ===----------------------------------------------------------------------===
 */

#if !_ARCH_PPC

#include "int_lib.h"

/* Returns: convert a to a unsigned int, rounding toward zero.
 *          Negative values all become zero.
 */

/* Assumption: long double is an intel 80 bit floating point type padded with 6 bytes
 *             su_int is a 32 bit integral type
 *             value in long double is representable in su_int or is negative 
 */

/* gggg gggg gggg gggg gggg gggg gggg gggg | gggg gggg gggg gggg seee eeee eeee eeee |
 * 1mmm mmmm mmmm mmmm mmmm mmmm mmmm mmmm | mmmm mmmm mmmm mmmm mmmm mmmm mmmm mmmm
 */

COMPILER_RT_ABI su_int
__fixunsxfsi(long double a)
{
    long_double_bits fb;
    fb.f = a;
    int e = (fb.u.high.s.low & 0x00007FFF) - 16383;
    if (e < 0 || (fb.u.high.s.low & 0x00008000))
        return 0;
    if ((unsigned)e > sizeof(su_int) * CHAR_BIT)
        return ~(su_int)0;
    return fb.u.low.s.high >> (31 - e);
}

#endif /* !_ARCH_PPC */