1// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
2// See https://llvm.org/LICENSE.txt for license information.
3// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
4
5// long double __floatditf(long long x);
6// This file implements the PowerPC long long -> long double conversion
7
8#include "DD.h"
9
10long double __floatditf(int64_t a) {
11
12  static const double twop32 = 0x1.0p32;
13  static const double twop52 = 0x1.0p52;
14
15  doublebits low = {.d = twop52};
16  low.x |= a & UINT64_C(0x00000000ffffffff); // 0x1.0p52 + low 32 bits of a.
17
18  const double high_addend = (double)((int32_t)(a >> 32)) * twop32 - twop52;
19
20  // At this point, we have two double precision numbers
21  // high_addend and low.d, and we wish to return their sum
22  // as a canonicalized long double:
23
24  // This implementation sets the inexact flag spuriously.
25  // This could be avoided, but at some substantial cost.
26
27  DD result;
28
29  result.s.hi = high_addend + low.d;
30  result.s.lo = (high_addend - result.s.hi) + low.d;
31
32  return result.ld;
33}
34