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/* ===-- ffsdi2.c - Implement __ffsdi2 -------------------------------------===
 *
 * Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 * See https://llvm.org/LICENSE.txt for license information.
 * SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 *
 * ===----------------------------------------------------------------------===
 *
 * This file implements __ffsdi2 for the compiler_rt library.
 *
 * ===----------------------------------------------------------------------===
 */

#include "int_lib.h"

/* Returns: the index of the least significant 1-bit in a, or
 * the value zero if a is zero. The least significant bit is index one.
 */

COMPILER_RT_ABI si_int __ffsdi2(di_int a) {
  dwords x;
  x.all = a;
  if (x.s.low == 0) {
    if (x.s.high == 0)
      return 0;
    return __builtin_ctz(x.s.high) + (1 + sizeof(si_int) * CHAR_BIT);
  }
  return __builtin_ctz(x.s.low) + 1;
}
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