xref: /aosp_15_r20/external/compiler-rt/lib/builtins/fixunsxfti.c (revision 7c3d14c8b49c529e04be81a3ce6f5cc23712e4c6)
1*7c3d14c8STreehugger Robot /* ===-- fixunsxfti.c - Implement __fixunsxfti -----------------------------===
2*7c3d14c8STreehugger Robot  *
3*7c3d14c8STreehugger Robot  *      	       The LLVM Compiler Infrastructure
4*7c3d14c8STreehugger Robot  *
5*7c3d14c8STreehugger Robot  * This file is dual licensed under the MIT and the University of Illinois Open
6*7c3d14c8STreehugger Robot  * Source Licenses. See LICENSE.TXT for details.
7*7c3d14c8STreehugger Robot  *
8*7c3d14c8STreehugger Robot  * ===----------------------------------------------------------------------===
9*7c3d14c8STreehugger Robot  *
10*7c3d14c8STreehugger Robot  * This file implements __fixunsxfti for the compiler_rt library.
11*7c3d14c8STreehugger Robot  *
12*7c3d14c8STreehugger Robot  * ===----------------------------------------------------------------------===
13*7c3d14c8STreehugger Robot  */
14*7c3d14c8STreehugger Robot 
15*7c3d14c8STreehugger Robot #include "int_lib.h"
16*7c3d14c8STreehugger Robot 
17*7c3d14c8STreehugger Robot #ifdef CRT_HAS_128BIT
18*7c3d14c8STreehugger Robot 
19*7c3d14c8STreehugger Robot /* Returns: convert a to a unsigned long long, rounding toward zero.
20*7c3d14c8STreehugger Robot  *          Negative values all become zero.
21*7c3d14c8STreehugger Robot  */
22*7c3d14c8STreehugger Robot 
23*7c3d14c8STreehugger Robot /* Assumption: long double is an intel 80 bit floating point type padded with 6 bytes
24*7c3d14c8STreehugger Robot  *             tu_int is a 128 bit integral type
25*7c3d14c8STreehugger Robot  *             value in long double is representable in tu_int or is negative
26*7c3d14c8STreehugger Robot  */
27*7c3d14c8STreehugger Robot 
28*7c3d14c8STreehugger Robot /* gggg gggg gggg gggg gggg gggg gggg gggg | gggg gggg gggg gggg seee eeee eeee eeee |
29*7c3d14c8STreehugger Robot  * 1mmm mmmm mmmm mmmm mmmm mmmm mmmm mmmm | mmmm mmmm mmmm mmmm mmmm mmmm mmmm mmmm
30*7c3d14c8STreehugger Robot  */
31*7c3d14c8STreehugger Robot 
32*7c3d14c8STreehugger Robot COMPILER_RT_ABI tu_int
__fixunsxfti(long double a)33*7c3d14c8STreehugger Robot __fixunsxfti(long double a)
34*7c3d14c8STreehugger Robot {
35*7c3d14c8STreehugger Robot     long_double_bits fb;
36*7c3d14c8STreehugger Robot     fb.f = a;
37*7c3d14c8STreehugger Robot     int e = (fb.u.high.s.low & 0x00007FFF) - 16383;
38*7c3d14c8STreehugger Robot     if (e < 0 || (fb.u.high.s.low & 0x00008000))
39*7c3d14c8STreehugger Robot         return 0;
40*7c3d14c8STreehugger Robot     if ((unsigned)e > sizeof(tu_int) * CHAR_BIT)
41*7c3d14c8STreehugger Robot         return ~(tu_int)0;
42*7c3d14c8STreehugger Robot     tu_int r = fb.u.low.all;
43*7c3d14c8STreehugger Robot     if (e > 63)
44*7c3d14c8STreehugger Robot         r <<= (e - 63);
45*7c3d14c8STreehugger Robot     else
46*7c3d14c8STreehugger Robot         r >>= (63 - e);
47*7c3d14c8STreehugger Robot     return r;
48*7c3d14c8STreehugger Robot }
49*7c3d14c8STreehugger Robot 
50*7c3d14c8STreehugger Robot #endif /* CRT_HAS_128BIT */
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