1 /* ===-- fixxfdi.c - Implement __fixxfdi -----------------------------------===
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 __fixxfdi for the compiler_rt library.
11 *
12 * ===----------------------------------------------------------------------===
13 */
14
15 #if !_ARCH_PPC
16
17 #include "int_lib.h"
18
19 /* Returns: convert a to a signed long long, rounding toward zero. */
20
21 /* Assumption: long double is an intel 80 bit floating point type padded with 6 bytes
22 * di_int is a 64 bit integral type
23 * value in long double is representable in di_int (no range checking performed)
24 */
25
26 /* gggg gggg gggg gggg gggg gggg gggg gggg | gggg gggg gggg gggg seee eeee eeee eeee |
27 * 1mmm mmmm mmmm mmmm mmmm mmmm mmmm mmmm | mmmm mmmm mmmm mmmm mmmm mmmm mmmm mmmm
28 */
29
30 COMPILER_RT_ABI di_int
__fixxfdi(long double a)31 __fixxfdi(long double a)
32 {
33 const di_int di_max = (di_int)((~(du_int)0) / 2);
34 const di_int di_min = -di_max - 1;
35 long_double_bits fb;
36 fb.f = a;
37 int e = (fb.u.high.s.low & 0x00007FFF) - 16383;
38 if (e < 0)
39 return 0;
40 if ((unsigned)e >= sizeof(di_int) * CHAR_BIT)
41 return a > 0 ? di_max : di_min;
42 di_int s = -(si_int)((fb.u.high.s.low & 0x00008000) >> 15);
43 di_int r = fb.u.low.all;
44 r = (du_int)r >> (63 - e);
45 return (r ^ s) - s;
46 }
47
48 #endif /* !_ARCH_PPC */
49