1/*===-- ashrdi3.c - Implement __ashrdi3 -----------------------------------===
2 *
3 *                     The LLVM Compiler Infrastructure
4 *
5 * This file is distributed under the University of Illinois Open Source
6 * License. See LICENSE.TXT for details.
7 *
8 * ===----------------------------------------------------------------------===
9 *
10 * This file implements __ashrdi3 for the compiler_rt library.
11 *
12 * ===----------------------------------------------------------------------===
13 */
14
15#include "int_lib.h"
16
17/* Returns: arithmetic a >> b */
18
19/* Precondition:  0 <= b < bits_in_dword */
20
21di_int
22__ashrdi3(di_int a, si_int b)
23{
24    const int bits_in_word = (int)(sizeof(si_int) * CHAR_BIT);
25    dwords input;
26    dwords result;
27    input.all = a;
28    if (b & bits_in_word)  /* bits_in_word <= b < bits_in_dword */
29    {
30        /* result.s.high = input.s.high < 0 ? -1 : 0 */
31        result.s.high = input.s.high >> (bits_in_word - 1);
32        result.s.low = input.s.high >> (b - bits_in_word);
33    }
34    else  /* 0 <= b < bits_in_word */
35    {
36        if (b == 0)
37            return a;
38        result.s.high  = input.s.high >> b;
39        result.s.low = (input.s.high << (bits_in_word - b)) | (input.s.low >> b);
40    }
41    return result.all;
42}
43