xref: /minix3/sys/external/bsd/compiler_rt/dist/lib/builtins/fixdfti.c (revision 0a6a1f1d05b60e214de2f05a7310ddd1f0e590e7)
1*0a6a1f1dSLionel Sambuc /* ===-- fixdfti.c - Implement __fixdfti -----------------------------------===
2*0a6a1f1dSLionel Sambuc  *
3*0a6a1f1dSLionel Sambuc  *                     The LLVM Compiler Infrastructure
4*0a6a1f1dSLionel Sambuc  *
5*0a6a1f1dSLionel Sambuc  * This file is dual licensed under the MIT and the University of Illinois Open
6*0a6a1f1dSLionel Sambuc  * Source Licenses. See LICENSE.TXT for details.
7*0a6a1f1dSLionel Sambuc  *
8*0a6a1f1dSLionel Sambuc  * ===----------------------------------------------------------------------===
9*0a6a1f1dSLionel Sambuc  *
10*0a6a1f1dSLionel Sambuc  * This file implements __fixdfti for the compiler_rt library.
11*0a6a1f1dSLionel Sambuc  *
12*0a6a1f1dSLionel Sambuc  * ===----------------------------------------------------------------------===
13*0a6a1f1dSLionel Sambuc  */
14*0a6a1f1dSLionel Sambuc 
15*0a6a1f1dSLionel Sambuc #include "int_lib.h"
16*0a6a1f1dSLionel Sambuc 
17*0a6a1f1dSLionel Sambuc #ifdef CRT_HAS_128BIT
18*0a6a1f1dSLionel Sambuc 
19*0a6a1f1dSLionel Sambuc /* Returns: convert a to a signed long long, rounding toward zero. */
20*0a6a1f1dSLionel Sambuc 
21*0a6a1f1dSLionel Sambuc /* Assumption: double is a IEEE 64 bit floating point type
22*0a6a1f1dSLionel Sambuc  *             su_int is a 32 bit integral type
23*0a6a1f1dSLionel Sambuc  *             value in double is representable in ti_int (no range checking performed)
24*0a6a1f1dSLionel Sambuc  */
25*0a6a1f1dSLionel Sambuc 
26*0a6a1f1dSLionel Sambuc /* seee eeee eeee mmmm mmmm mmmm mmmm mmmm | mmmm mmmm mmmm mmmm mmmm mmmm mmmm mmmm */
27*0a6a1f1dSLionel Sambuc 
28*0a6a1f1dSLionel Sambuc COMPILER_RT_ABI ti_int
__fixdfti(double a)29*0a6a1f1dSLionel Sambuc __fixdfti(double a)
30*0a6a1f1dSLionel Sambuc {
31*0a6a1f1dSLionel Sambuc     double_bits fb;
32*0a6a1f1dSLionel Sambuc     fb.f = a;
33*0a6a1f1dSLionel Sambuc     int e = ((fb.u.s.high & 0x7FF00000) >> 20) - 1023;
34*0a6a1f1dSLionel Sambuc     if (e < 0)
35*0a6a1f1dSLionel Sambuc         return 0;
36*0a6a1f1dSLionel Sambuc     ti_int s = (si_int)(fb.u.s.high & 0x80000000) >> 31;
37*0a6a1f1dSLionel Sambuc     ti_int r = 0x0010000000000000uLL | (0x000FFFFFFFFFFFFFuLL & fb.u.all);
38*0a6a1f1dSLionel Sambuc     if (e > 52)
39*0a6a1f1dSLionel Sambuc         r <<= (e - 52);
40*0a6a1f1dSLionel Sambuc     else
41*0a6a1f1dSLionel Sambuc         r >>= (52 - e);
42*0a6a1f1dSLionel Sambuc     return (r ^ s) - s;
43*0a6a1f1dSLionel Sambuc }
44*0a6a1f1dSLionel Sambuc 
45*0a6a1f1dSLionel Sambuc #endif /* CRT_HAS_128BIT */
46