xref: /openbsd-src/gnu/llvm/compiler-rt/lib/builtins/absvsi2.c (revision 1f9cb04fc6f537ca6cf5a53c28927340cba218a2)
13cab2bb3Spatrick //===-- absvsi2.c - Implement __absvsi2 -----------------------------------===//
23cab2bb3Spatrick //
33cab2bb3Spatrick // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
43cab2bb3Spatrick // See https://llvm.org/LICENSE.txt for license information.
53cab2bb3Spatrick // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
63cab2bb3Spatrick //
73cab2bb3Spatrick //===----------------------------------------------------------------------===//
83cab2bb3Spatrick //
93cab2bb3Spatrick // This file implements __absvsi2 for the compiler_rt library.
103cab2bb3Spatrick //
113cab2bb3Spatrick //===----------------------------------------------------------------------===//
123cab2bb3Spatrick 
133cab2bb3Spatrick #include "int_lib.h"
143cab2bb3Spatrick 
153cab2bb3Spatrick // Returns: absolute value
163cab2bb3Spatrick 
173cab2bb3Spatrick // Effects: aborts if abs(x) < 0
183cab2bb3Spatrick 
__absvsi2(si_int a)193cab2bb3Spatrick COMPILER_RT_ABI si_int __absvsi2(si_int a) {
203cab2bb3Spatrick   const int N = (int)(sizeof(si_int) * CHAR_BIT);
21*1f9cb04fSpatrick   if (a == ((si_int)1 << (N - 1)))
223cab2bb3Spatrick     compilerrt_abort();
233cab2bb3Spatrick   const si_int t = a >> (N - 1);
243cab2bb3Spatrick   return (a ^ t) - t;
253cab2bb3Spatrick }
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