xref: /aosp_15_r20/external/compiler-rt/lib/builtins/ashrti3.c (revision 7c3d14c8b49c529e04be81a3ce6f5cc23712e4c6)
1*7c3d14c8STreehugger Robot /* ===-- ashrti3.c - Implement __ashrti3 -----------------------------------===
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 __ashrti3 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: arithmetic a >> b */
20*7c3d14c8STreehugger Robot 
21*7c3d14c8STreehugger Robot /* Precondition:  0 <= b < bits_in_tword */
22*7c3d14c8STreehugger Robot 
23*7c3d14c8STreehugger Robot COMPILER_RT_ABI ti_int
__ashrti3(ti_int a,si_int b)24*7c3d14c8STreehugger Robot __ashrti3(ti_int a, si_int b)
25*7c3d14c8STreehugger Robot {
26*7c3d14c8STreehugger Robot     const int bits_in_dword = (int)(sizeof(di_int) * CHAR_BIT);
27*7c3d14c8STreehugger Robot     twords input;
28*7c3d14c8STreehugger Robot     twords result;
29*7c3d14c8STreehugger Robot     input.all = a;
30*7c3d14c8STreehugger Robot     if (b & bits_in_dword)  /* bits_in_dword <= b < bits_in_tword */
31*7c3d14c8STreehugger Robot     {
32*7c3d14c8STreehugger Robot         /* result.s.high = input.s.high < 0 ? -1 : 0 */
33*7c3d14c8STreehugger Robot         result.s.high = input.s.high >> (bits_in_dword - 1);
34*7c3d14c8STreehugger Robot         result.s.low = input.s.high >> (b - bits_in_dword);
35*7c3d14c8STreehugger Robot     }
36*7c3d14c8STreehugger Robot     else  /* 0 <= b < bits_in_dword */
37*7c3d14c8STreehugger Robot     {
38*7c3d14c8STreehugger Robot         if (b == 0)
39*7c3d14c8STreehugger Robot             return a;
40*7c3d14c8STreehugger Robot         result.s.high  = input.s.high >> b;
41*7c3d14c8STreehugger Robot         result.s.low = (input.s.high << (bits_in_dword - b)) | (input.s.low >> b);
42*7c3d14c8STreehugger Robot     }
43*7c3d14c8STreehugger Robot     return result.all;
44*7c3d14c8STreehugger Robot }
45*7c3d14c8STreehugger Robot 
46*7c3d14c8STreehugger Robot #endif /* CRT_HAS_128BIT */
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