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 
__floatditf(int64_t a)10 long 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