ashldi3.c revision 2d1fdb26e458c4ddc04155c1d421bced3ba90cd0 
1/* ====-- ashldi3.c - Implement __ashldi3 -----------------------------------===
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 __ashldi3 for the compiler_rt library.
11 *
12 * ===----------------------------------------------------------------------===
13 */
14
15#include "int_lib.h"
16
17/* Returns: a << b */
18
19/* Precondition:  0 <= b < bits_in_dword */
20
21ARM_EABI_FNALIAS(llsl, ashldi3)
22
23COMPILER_RT_ABI di_int
24__ashldi3(di_int a, si_int b)
25{
26    const int bits_in_word = (int)(sizeof(si_int) * CHAR_BIT);
27    dwords input;
28    dwords result;
29    input.all = a;
30    if (b & bits_in_word)  /* bits_in_word <= b < bits_in_dword */
31    {
32        result.s.low = 0;
33        result.s.high = input.s.low << (b - bits_in_word);
34    }
35    else  /* 0 <= b < bits_in_word */
36    {
37        if (b == 0)
38            return a;
39        result.s.low  = input.s.low << b;
40        result.s.high = (input.s.high << b) | (input.s.low >> (bits_in_word - b));
41    }
42    return result.all;
43}
44