1 /* ===-- fixunsdfdi.c - Implement __fixunsdfdi -----------------------------===
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 __fixunsdfdi for the compiler_rt library.
11 *
12 * ===----------------------------------------------------------------------===
13 */
14
15 #include "int_lib.h"
16
17 /* Returns: convert a to a unsigned long long, rounding toward zero.
18 * Negative values all become zero.
19 */
20
21 /* Assumption: double is a IEEE 64 bit floating point type
22 * du_int is a 64 bit integral type
23 * value in double is representable in du_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 du_int
__fixunsdfdi(double a)30 __fixunsdfdi(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 udwords r;
38 r.s.high = (fb.u.s.high & 0x000FFFFF) | 0x00100000;
39 r.s.low = fb.u.s.low;
40 if (e > 52)
41 r.all <<= (e - 52);
42 else
43 r.all >>= (52 - e);
44 return r.all;
45 }
46