llvm-project

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//===-- ffsdi2.c - Implement __ffsdi2 -------------------------------------===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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//
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// This file implements __ffsdi2 for the compiler_rt library.
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//
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//===----------------------------------------------------------------------===//
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#include "int_lib.h"
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// Returns: the index of the least significant 1-bit in a, or
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// the value zero if a is zero. The least significant bit is index one.
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COMPILER_RT_ABI int __ffsdi2(di_int a) {
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  dwords x;
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  x.all = a;
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  if (x.s.low == 0) {
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    if (x.s.high == 0)
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      return 0;
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    return ctzsi(x.s.high) + (1 + sizeof(si_int) * CHAR_BIT);
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  }
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  return ctzsi(x.s.low) + 1;
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}
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