1 /* ===-- fixunsdfti.c - Implement __fixunsdfti -----------------------------===
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 __fixunsdfti for the compiler_rt library.
11 *
12 * ===----------------------------------------------------------------------===
13 */
14
15 #include "int_lib.h"
16
17 #if __x86_64
18
19 /* Returns: convert a to a unsigned long long, rounding toward zero.
20 * Negative values all become zero.
21 */
22
23 /* Assumption: double is a IEEE 64 bit floating point type
24 * tu_int is a 64 bit integral type
25 * value in double is representable in tu_int or is negative
26 * (no range checking performed)
27 */
28
29 /* seee eeee eeee mmmm mmmm mmmm mmmm mmmm | mmmm mmmm mmmm mmmm mmmm mmmm mmmm mmmm */
30
31 tu_int
__fixunsdfti(double a)32 __fixunsdfti(double a)
33 {
34 double_bits fb;
35 fb.f = a;
36 int e = ((fb.u.s.high & 0x7FF00000) >> 20) - 1023;
37 if (e < 0 || (fb.u.s.high & 0x80000000))
38 return 0;
39 tu_int r = 0x0010000000000000uLL | (fb.u.all & 0x000FFFFFFFFFFFFFuLL);
40 if (e > 52)
41 r <<= (e - 52);
42 else
43 r >>= (52 - e);
44 return r;
45 }
46
47 #endif
48