1 /* ===-- lshrdi3.c - Implement __lshrdi3 -----------------------------------===
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 __lshrdi3 for the compiler_rt library.
11  *
12  * ===----------------------------------------------------------------------===
13  */
14 
15 #include "int_lib.h"
16 
17 /* Returns: logical a >> b */
18 
19 /* Precondition:  0 <= b < bits_in_dword */
20 
21 COMPILER_RT_ABI di_int
__lshrdi3(di_int a,si_int b)22 __lshrdi3(di_int a, si_int b)
23 {
24     const int bits_in_word = (int)(sizeof(si_int) * CHAR_BIT);
25     udwords input;
26     udwords result;
27     input.all = a;
28     if (b & bits_in_word)  /* bits_in_word <= b < bits_in_dword */
29     {
30         result.s.high = 0;
31         result.s.low = input.s.high >> (b - bits_in_word);
32     }
33     else  /* 0 <= b < bits_in_word */
34     {
35         if (b == 0)
36             return a;
37         result.s.high  = input.s.high >> b;
38         result.s.low = (input.s.high << (bits_in_word - b)) | (input.s.low >> b);
39     }
40     return result.all;
41 }
42 
43 #if defined(__ARM_EABI__)
44 AEABI_RTABI di_int __aeabi_llsr(di_int a, si_int b) COMPILER_RT_ALIAS(__lshrdi3);
45 #endif
46