0ba22f51d1
Use the uniform single line C++/99 style for code comments. This is part of the cleanup proposed in "[RFC] compiler-rt builtins cleanup and refactoring". Differential Revision: https://reviews.llvm.org/D60352 llvm-svn: 359411
40 lines
1.3 KiB
C
40 lines
1.3 KiB
C
// 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 __floatunditf(unsigned long long x);
|
|
// This file implements the PowerPC unsigned long long -> long double conversion
|
|
|
|
#include "DD.h"
|
|
|
|
long double __floatunditf(uint64_t a) {
|
|
|
|
// Begins with an exact copy of the code from __floatundidf
|
|
|
|
static const double twop52 = 0x1.0p52;
|
|
static const double twop84 = 0x1.0p84;
|
|
static const double twop84_plus_twop52 = 0x1.00000001p84;
|
|
|
|
doublebits high = {.d = twop84};
|
|
doublebits low = {.d = twop52};
|
|
|
|
high.x |= a >> 32; // 0x1.0p84 + high 32 bits of a
|
|
low.x |= a & UINT64_C(0x00000000ffffffff); // 0x1.0p52 + low 32 bits of a
|
|
|
|
const double high_addend = high.d - twop84_plus_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;
|
|
}
|