1//===-- ashlti3.c - Implement __ashlti3 -----------------------------------===//
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 __ashlti3 for the compiler_rt library.
10//
11//===----------------------------------------------------------------------===//
12
13#include "int_lib.h"
14
15#ifdef CRT_HAS_128BIT
16
17// Returns: a << b
18
19// Precondition:  0 <= b < bits_in_tword
20
21COMPILER_RT_ABI ti_int __ashlti3(ti_int a, si_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.low = 0;
28    result.s.high = input.s.low << (b - bits_in_dword);
29  } else /* 0 <= b < bits_in_dword */ {
30    if (b == 0)
31      return a;
32    result.s.low = input.s.low << b;
33    result.s.high = (input.s.high << b) | (input.s.low >> (bits_in_dword - b));
34  }
35  return result.all;
36}
37
38#endif // CRT_HAS_128BIT
39