| 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 | |
|---|
| 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 | |
|---|
