1 /* ===-- fixsfti.c - Implement __fixsfti -----------------------------------===
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 __fixsfti 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: float is a IEEE 32 bit floating point type
22  *             su_int is a 32 bit integral type
23  *             value in float is representable in ti_int (no range checking performed)
24  */
25 
26 /* seee eeee emmm mmmm mmmm mmmm mmmm mmmm */
27 
28 COMPILER_RT_ABI ti_int
29 __fixsfti(float a)
30 {
31     float_bits fb;
32     fb.f = a;
33     int e = ((fb.u & 0x7F800000) >> 23) - 127;
34     if (e < 0)
35         return 0;
36     ti_int s = (si_int)(fb.u & 0x80000000) >> 31;
37     ti_int r = (fb.u & 0x007FFFFF) | 0x00800000;
38     if (e > 23)
39         r <<= (e - 23);
40     else
41         r >>= (23 - e);
42     return (r ^ s) - s;
43 }
44 
45 #endif /* CRT_HAS_128BIT */
46