xref: /openbsd-src/gnu/llvm/compiler-rt/lib/builtins/absvdi2.c (revision 3cab2bb3f667058bece8e38b12449a63a9d73c4b)
1*3cab2bb3Spatrick //===-- absvdi2.c - Implement __absvdi2 -----------------------------------===//
2*3cab2bb3Spatrick //
3*3cab2bb3Spatrick // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4*3cab2bb3Spatrick // See https://llvm.org/LICENSE.txt for license information.
5*3cab2bb3Spatrick // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6*3cab2bb3Spatrick //
7*3cab2bb3Spatrick //===----------------------------------------------------------------------===//
8*3cab2bb3Spatrick //
9*3cab2bb3Spatrick // This file implements __absvdi2 for the compiler_rt library.
10*3cab2bb3Spatrick //
11*3cab2bb3Spatrick //===----------------------------------------------------------------------===//
12*3cab2bb3Spatrick 
13*3cab2bb3Spatrick #include "int_lib.h"
14*3cab2bb3Spatrick 
15*3cab2bb3Spatrick // Returns: absolute value
16*3cab2bb3Spatrick 
17*3cab2bb3Spatrick // Effects: aborts if abs(x) < 0
18*3cab2bb3Spatrick 
__absvdi2(di_int a)19*3cab2bb3Spatrick COMPILER_RT_ABI di_int __absvdi2(di_int a) {
20*3cab2bb3Spatrick   const int N = (int)(sizeof(di_int) * CHAR_BIT);
21*3cab2bb3Spatrick   if (a == ((di_int)1 << (N - 1)))
22*3cab2bb3Spatrick     compilerrt_abort();
23*3cab2bb3Spatrick   const di_int t = a >> (N - 1);
24*3cab2bb3Spatrick   return (a ^ t) - t;
25*3cab2bb3Spatrick }
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