compiler-rt/lib/builtins/absvsi2.c

   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 }