xref: /freebsd/contrib/llvm-project/compiler-rt/lib/builtins/absvsi2.c (revision d37eb51047221dc3322b34db1038ff3aa533883f)
1 //===-- absvsi2.c - Implement __absvsi2 -----------------------------------===//
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 __absvsi2 for the compiler_rt library.
10 //
11 //===----------------------------------------------------------------------===//
12 
13 #include "int_lib.h"
14 
15 // Returns: absolute value
16 
17 // Effects: aborts if abs(x) < 0
18 
19 COMPILER_RT_ABI si_int __absvsi2(si_int a) {
20   const int N = (int)(sizeof(si_int) * CHAR_BIT);
21   if (a == ((si_int)((su_int)1 << (N - 1))))
22     compilerrt_abort();
23   const si_int t = a >> (N - 1);
24   return (a ^ t) - t;
25 }
26