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1 /* ===-- fixunsdfsi.c - Implement __fixunsdfsi -----------------------------===
2  *
3  *                     The LLVM Compiler Infrastructure
4  *
5  * This file is distributed under the University of Illinois Open Source
6  * License. See LICENSE.TXT for details.
7  *
8  * ===----------------------------------------------------------------------===
9  *
10  * This file implements __fixunsdfsi for the compiler_rt library.
11  *
12  * ===----------------------------------------------------------------------===
13  */
14 
15 #include "int_lib.h"
16 
17 /* Returns: convert a to a unsigned int, rounding toward zero.
18  *          Negative values all become zero.
19  */
20 
21 /* Assumption: double is a IEEE 64 bit floating point type
22  *             su_int is a 32 bit integral type
23  *             value in double is representable in su_int or is negative
24  *                 (no range checking performed)
25  */
26 
27 /* seee eeee eeee mmmm mmmm mmmm mmmm mmmm | mmmm mmmm mmmm mmmm mmmm mmmm mmmm mmmm */
28 
29 su_int
__fixunsdfsi(double a)30 __fixunsdfsi(double a)
31 {
32     double_bits fb;
33     fb.f = a;
34     int e = ((fb.u.s.high & 0x7FF00000) >> 20) - 1023;
35     if (e < 0 || (fb.u.s.high & 0x80000000))
36         return 0;
37     return (
38                 0x80000000u                      |
39                 ((fb.u.s.high & 0x000FFFFF) << 11) |
40                 (fb.u.s.low >> 21)
41            ) >> (31 - e);
42 }
43