compiler-rt/lib/builtins/paritysi2.c

   1 //===-- paritysi2.c - Implement __paritysi2 -------------------------------===//
   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 __paritysi2 for the compiler_rt library.
  10 //
  11 //===----------------------------------------------------------------------===//
  12
  13 #include "int_lib.h"
  14
  15 // Returns: 1 if number of bits is odd else returns 0
  16
  17 COMPILER_RT_ABI int __paritysi2(si_int a) {
  18   su_int x = (su_int)a;
  19   x ^= x >> 16;
  20   x ^= x >> 8;
  21   x ^= x >> 4;
  22   return (0x6996 >> (x & 0xF)) & 1;
  23 }