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
21COMPILER_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