lib/builtins/absvdi2.c

   1 /*===-- absvdi2.c - Implement __absvdi2 -----------------------------------===
   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 __absvdi2 for the compiler_rt library.
  11  *
  12  *===----------------------------------------------------------------------===
  13  */
  14
  15 #include "int_lib.h"
  16
  17 /* Returns: absolute value */
  18
  19 /* Effects: aborts if abs(x) < 0 */
  20
  21 COMPILER_RT_ABI di_int
  22 __absvdi2(di_int a)
  23 {
  24     const int N = (int)(sizeof(di_int) * CHAR_BIT);
  25     if (a == ((di_int)1 << (N-1)))
  26         compilerrt_abort();
  27     const di_int t = a >> (N - 1);
  28     return (a ^ t) - t;
  29 }