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/* 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
 */

/* long double __floatditf(long long x); */
/* This file implements the PowerPC long long -> long double conversion */

#include "DD.h"

long double __floatditf(int64_t a) {

  static const double twop32 = 0x1.0p32;
  static const double twop52 = 0x1.0p52;

  doublebits low = {.d = twop52};
  low.x |= a & UINT64_C(0x00000000ffffffff); /* 0x1.0p52 + low 32 bits of a. */

  const double high_addend = (double)((int32_t)(a >> 32)) * twop32 - twop52;

  /* At this point, we have two double precision numbers
   * high_addend and low.d, and we wish to return their sum
   * as a canonicalized long double:
   */

  /* This implementation sets the inexact flag spuriously.
   * This could be avoided, but at some substantial cost.
   */

  DD result;

  result.s.hi = high_addend + low.d;
  result.s.lo = (high_addend - result.s.hi) + low.d;

  return result.ld;
}
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