xref: /freebsd/contrib/llvm-project/compiler-rt/lib/builtins/ashlti3.c (revision 0b57cec536236d46e3dba9bd041533462f33dbb7)
1*0b57cec5SDimitry Andric //===-- ashlti3.c - Implement __ashlti3 -----------------------------------===//
2*0b57cec5SDimitry Andric //
3*0b57cec5SDimitry Andric // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4*0b57cec5SDimitry Andric // See https://llvm.org/LICENSE.txt for license information.
5*0b57cec5SDimitry Andric // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6*0b57cec5SDimitry Andric //
7*0b57cec5SDimitry Andric //===----------------------------------------------------------------------===//
8*0b57cec5SDimitry Andric //
9*0b57cec5SDimitry Andric // This file implements __ashlti3 for the compiler_rt library.
10*0b57cec5SDimitry Andric //
11*0b57cec5SDimitry Andric //===----------------------------------------------------------------------===//
12*0b57cec5SDimitry Andric 
13*0b57cec5SDimitry Andric #include "int_lib.h"
14*0b57cec5SDimitry Andric 
15*0b57cec5SDimitry Andric #ifdef CRT_HAS_128BIT
16*0b57cec5SDimitry Andric 
17*0b57cec5SDimitry Andric // Returns: a << b
18*0b57cec5SDimitry Andric 
19*0b57cec5SDimitry Andric // Precondition:  0 <= b < bits_in_tword
20*0b57cec5SDimitry Andric 
21*0b57cec5SDimitry Andric COMPILER_RT_ABI ti_int __ashlti3(ti_int a, si_int b) {
22*0b57cec5SDimitry Andric   const int bits_in_dword = (int)(sizeof(di_int) * CHAR_BIT);
23*0b57cec5SDimitry Andric   twords input;
24*0b57cec5SDimitry Andric   twords result;
25*0b57cec5SDimitry Andric   input.all = a;
26*0b57cec5SDimitry Andric   if (b & bits_in_dword) /* bits_in_dword <= b < bits_in_tword */ {
27*0b57cec5SDimitry Andric     result.s.low = 0;
28*0b57cec5SDimitry Andric     result.s.high = input.s.low << (b - bits_in_dword);
29*0b57cec5SDimitry Andric   } else /* 0 <= b < bits_in_dword */ {
30*0b57cec5SDimitry Andric     if (b == 0)
31*0b57cec5SDimitry Andric       return a;
32*0b57cec5SDimitry Andric     result.s.low = input.s.low << b;
33*0b57cec5SDimitry Andric     result.s.high = (input.s.high << b) | (input.s.low >> (bits_in_dword - b));
34*0b57cec5SDimitry Andric   }
35*0b57cec5SDimitry Andric   return result.all;
36*0b57cec5SDimitry Andric }
37*0b57cec5SDimitry Andric 
38*0b57cec5SDimitry Andric #endif // CRT_HAS_128BIT
39