fixunsdfdi.c revision 222656 
1/* ===-- fixunsdfdi.c - Implement __fixunsdfdi -----------------------------===
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 __fixunsdfdi for the compiler_rt library.
11 *
12 * ===----------------------------------------------------------------------===
13 */
14#include "abi.h"
15
16#include "int_lib.h"
17
18/* Returns: convert a to a unsigned long long, rounding toward zero.
19 *          Negative values all become zero.
20 */
21
22/* Assumption: double is a IEEE 64 bit floating point type
23 *             du_int is a 64 bit integral type
24 *             value in double is representable in du_int or is negative
25 *                 (no range checking performed)
26 */
27
28/* seee eeee eeee mmmm mmmm mmmm mmmm mmmm | mmmm mmmm mmmm mmmm mmmm mmmm mmmm mmmm */
29
30ARM_EABI_FNALIAS(d2ulz, fixunsdfdi);
31
32COMPILER_RT_ABI du_int
33__fixunsdfdi(double a)
34{
35    double_bits fb;
36    fb.f = a;
37    int e = ((fb.u.s.high & 0x7FF00000) >> 20) - 1023;
38    if (e < 0 || (fb.u.s.high & 0x80000000))
39        return 0;
40    udwords r;
41    r.s.high = (fb.u.s.high & 0x000FFFFF) | 0x00100000;
42    r.s.low = fb.u.s.low;
43    if (e > 52)
44        r.all <<= (e - 52);
45    else
46        r.all >>= (52 - e);
47    return r.all;
48}
49