lib/builtins/paritysi2.c

   1 /* ===-- paritysi2.c - Implement __paritysi2 -------------------------------===
   2  *
   3  *                     The LLVM Compiler Infrastructure
   4  *
   5  * This file is dual licensed under the MIT and the University of Illinois Open
   6  * Source Licenses. See LICENSE.TXT for details.
   7  *
   8  * ===----------------------------------------------------------------------===
   9  *
  10  * This file implements __paritysi2 for the compiler_rt library.
  11  *
  12  * ===----------------------------------------------------------------------===
  13  */
  14
  15 #include "int_lib.h"
  16
  17 /* Returns: 1 if number of bits is odd else returns 0 */
  18
  19 COMPILER_RT_ABI si_int
  20 __paritysi2(si_int a)
  21 {
  22     su_int x = (su_int)a;
  23     x ^= x >> 16;
  24     x ^= x >> 8;
  25     x ^= x >> 4;
  26     return (0x6996 >> (x & 0xF)) & 1;
  27 }