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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