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1a4d82fc JJ |
1 | /* ===-- fixxfti.c - Implement __fixxfti -----------------------------------=== |
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 __fixxfti for the compiler_rt library. | |
11 | * | |
12 | * ===----------------------------------------------------------------------=== | |
13 | */ | |
14 | ||
15 | #include "int_lib.h" | |
16 | ||
17 | #ifdef CRT_HAS_128BIT | |
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 | |
92a42be0 SL |
22 | * ti_int is a 128 bit integral type |
23 | * value in long double is representable in ti_int | |
1a4d82fc JJ |
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 ti_int | |
31 | __fixxfti(long double a) | |
32 | { | |
92a42be0 SL |
33 | const ti_int ti_max = (ti_int)((~(tu_int)0) / 2); |
34 | const ti_int ti_min = -ti_max - 1; | |
1a4d82fc JJ |
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 | ti_int s = -(si_int)((fb.u.high.s.low & 0x00008000) >> 15); | |
41 | ti_int r = fb.u.low.all; | |
92a42be0 SL |
42 | if ((unsigned)e >= sizeof(ti_int) * CHAR_BIT) |
43 | return a > 0 ? ti_max : ti_min; | |
1a4d82fc JJ |
44 | if (e > 63) |
45 | r <<= (e - 63); | |
46 | else | |
47 | r >>= (63 - e); | |
48 | return (r ^ s) - s; | |
49 | } | |
50 | ||
51 | #endif /* CRT_HAS_128BIT */ |