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1 /* ===-- lshrti3.c - Implement __lshrti3 -----------------------------------===
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 __lshrti3 for the compiler_rt library.
11  *
12  * ===----------------------------------------------------------------------===
13  */
14 
15 #include "int_lib.h"
16 
17 #ifdef CRT_HAS_128BIT
18 
19 /* Returns: logical a >> b */
20 
21 /* Precondition:  0 <= b < bits_in_tword */
22 
23 COMPILER_RT_ABI ti_int
__lshrti3(ti_int a,si_int b)24 __lshrti3(ti_int a, si_int b)
25 {
26     const int bits_in_dword = (int)(sizeof(di_int) * CHAR_BIT);
27     utwords input;
28     utwords result;
29     input.all = a;
30     if (b & bits_in_dword)  /* bits_in_dword <= b < bits_in_tword */
31     {
32         result.s.high = 0;
33         result.s.low = input.s.high >> (b - bits_in_dword);
34     }
35     else  /* 0 <= b < bits_in_dword */
36     {
37         if (b == 0)
38             return a;
39         result.s.high  = input.s.high >> b;
40         result.s.low = (input.s.high << (bits_in_dword - b)) | (input.s.low >> b);
41     }
42     return result.all;
43 }
44 
45 #endif /* CRT_HAS_128BIT */
46