1 //===-- ashrti3.c - Implement __ashrti3 -----------------------------------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 //
9 // This file implements __ashrti3 for the compiler_rt library.
10 //
11 //===----------------------------------------------------------------------===//
12 
13 #include "int_lib.h"
14 
15 #ifdef CRT_HAS_128BIT
16 
17 // Returns: arithmetic a >> b
18 
19 // Precondition:  0 <= b < bits_in_tword
20 
21 COMPILER_RT_ABI ti_int __ashrti3(ti_int a, int b) {
22   const int bits_in_dword = (int)(sizeof(di_int) * CHAR_BIT);
23   twords input;
24   twords result;
25   input.all = a;
26   if (b & bits_in_dword) /* bits_in_dword <= b < bits_in_tword */ {
27     // result.s.high = input.s.high < 0 ? -1 : 0
28     result.s.high = input.s.high >> (bits_in_dword - 1);
29     result.s.low = input.s.high >> (b - bits_in_dword);
30   } else /* 0 <= b < bits_in_dword */ {
31     if (b == 0)
32       return a;
33     result.s.high = input.s.high >> b;
34     result.s.low =
35         ((du_int)input.s.high << (bits_in_dword - b)) | (input.s.low >> b);
36   }
37   return result.all;
38 }
39 
40 #endif // CRT_HAS_128BIT
41