1 /* ===-- fixunsxfti.c - Implement __fixunsxfti -----------------------------===
2 *
3 * The LLVM Compiler Infrastructure
4 *
5 * This file is dual licensed under the MIT and the University of Illinois Open
6 * Source Licenses. See LICENSE.TXT for details.
7 *
8 * ===----------------------------------------------------------------------===
9 *
10 * This file implements __fixunsxfti for the compiler_rt library.
11 *
12 * ===----------------------------------------------------------------------===
13 */
14
15 #if __x86_64
16
17 #include "int_lib.h"
18
19 /* Returns: convert a to a unsigned long long, rounding toward zero.
20 * Negative values all become zero.
21 */
22
23 /* Assumption: long double is an intel 80 bit floating point type padded with 6 bytes
24 * tu_int is a 64 bit integral type
25 * value in long double is representable in tu_int or is negative
26 * (no range checking performed)
27 */
28
29 /* gggg gggg gggg gggg gggg gggg gggg gggg | gggg gggg gggg gggg seee eeee eeee eeee |
30 * 1mmm mmmm mmmm mmmm mmmm mmmm mmmm mmmm | mmmm mmmm mmmm mmmm mmmm mmmm mmmm mmmm
31 */
32
33 tu_int
__fixunsxfti(long double a)34 __fixunsxfti(long double a)
35 {
36 long_double_bits fb;
37 fb.f = a;
38 int e = (fb.u.high.s.low & 0x00007FFF) - 16383;
39 if (e < 0 || (fb.u.high.s.low & 0x00008000))
40 return 0;
41 tu_int r = fb.u.low.all;
42 if (e > 63)
43 r <<= (e - 63);
44 else
45 r >>= (63 - e);
46 return r;
47 }
48
49 #endif
50