aboutsummaryrefslogtreecommitdiffstats
path: root/contrib/libs/cxxsupp/builtins/lshrti3.c
blob: e4170ff84a5a6db639e35a0b07f7072134c5140f (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
/* ===-- lshrti3.c - Implement __lshrti3 -----------------------------------===
 *
 *                     The LLVM Compiler Infrastructure
 *
 * This file is dual licensed under the MIT and the University of Illinois Open
 * Source Licenses. See LICENSE.TXT for details.
 *
 * ===----------------------------------------------------------------------===
 *
 * This file implements __lshrti3 for the compiler_rt library.
 *
 * ===----------------------------------------------------------------------===
 */

#include "int_lib.h"

#ifdef CRT_HAS_128BIT

/* Returns: logical a >> b */

/* Precondition:  0 <= b < bits_in_tword */

COMPILER_RT_ABI ti_int
__lshrti3(ti_int a, si_int b)
{
    const int bits_in_dword = (int)(sizeof(di_int) * CHAR_BIT);
    utwords input;
    utwords result;
    input.all = a;
    if (b & bits_in_dword)  /* bits_in_dword <= b < bits_in_tword */
    {
        result.s.high = 0;
        result.s.low = input.s.high >> (b - bits_in_dword);
    }
    else  /* 0 <= b < bits_in_dword */
    {
        if (b == 0)
            return a;
        result.s.high  = input.s.high >> b;
        result.s.low = (input.s.high << (bits_in_dword - b)) | (input.s.low >> b);
    }
    return result.all;
}

#endif /* CRT_HAS_128BIT */