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 #include "int_lib.h"
16
17 #ifdef CRT_HAS_128BIT
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 128 bit integral type
25 * value in long double is representable in tu_int or is negative
26 */
27
28 /* gggg gggg gggg gggg gggg gggg gggg gggg | gggg gggg gggg gggg seee eeee eeee eeee |
29 * 1mmm mmmm mmmm mmmm mmmm mmmm mmmm mmmm | mmmm mmmm mmmm mmmm mmmm mmmm mmmm mmmm
30 */
31
32 COMPILER_RT_ABI tu_int
__fixunsxfti(long double a)33 __fixunsxfti(long double a)
34 {
35 long_double_bits fb;
36 fb.f = a;
37 int e = (fb.u.high.s.low & 0x00007FFF) - 16383;
38 if (e < 0 || (fb.u.high.s.low & 0x00008000))
39 return 0;
40 if ((unsigned)e > sizeof(tu_int) * CHAR_BIT)
41 return ~(tu_int)0;
42 tu_int r = fb.u.low.all;
43 if (e > 63)
44 r <<= (e - 63);
45 else
46 r >>= (63 - e);
47 return r;
48 }
49
50 #endif /* CRT_HAS_128BIT */
51