1 | /* ===-- ashrti3.c - Implement __ashrti3 -----------------------------------=== |
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 __ashrti3 for the compiler_rt library. |
11 | * |
12 | * ===----------------------------------------------------------------------=== |
13 | */ |
14 | |
15 | #include "int_lib.h" |
16 | |
17 | #ifdef CRT_HAS_128BIT |
18 | |
19 | /* Returns: arithmetic a >> b */ |
20 | |
21 | /* Precondition: 0 <= b < bits_in_tword */ |
22 | |
23 | COMPILER_RT_ABI ti_int |
24 | __ashrti3(ti_int a, si_int b) |
25 | { |
26 | const int bits_in_dword = (int)(sizeof(di_int) * CHAR_BIT); |
27 | twords input; |
28 | twords result; |
29 | input.all = a; |
30 | if (b & bits_in_dword) /* bits_in_dword <= b < bits_in_tword */ |
31 | { |
32 | /* result.s.high = input.s.high < 0 ? -1 : 0 */ |
33 | result.s.high = input.s.high >> (bits_in_dword - 1); |
34 | result.s.low = input.s.high >> (b - bits_in_dword); |
35 | } |
36 | else /* 0 <= b < bits_in_dword */ |
37 | { |
38 | if (b == 0) |
39 | return a; |
40 | result.s.high = input.s.high >> b; |
41 | result.s.low = (input.s.high << (bits_in_dword - b)) | (input.s.low >> b); |
42 | } |
43 | return result.all; |
44 | } |
45 | |
46 | #endif /* CRT_HAS_128BIT */ |
47 | |