1*0b57cec5SDimitry Andric // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 2*0b57cec5SDimitry Andric // See https://llvm.org/LICENSE.txt for license information. 3*0b57cec5SDimitry Andric // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 4*0b57cec5SDimitry Andric 5*0b57cec5SDimitry Andric // long double __floatditf(long long x); 6*0b57cec5SDimitry Andric // This file implements the PowerPC long long -> long double conversion 7*0b57cec5SDimitry Andric 8*0b57cec5SDimitry Andric #include "DD.h" 9*0b57cec5SDimitry Andric __floatditf(int64_t a)10*0b57cec5SDimitry Andriclong double __floatditf(int64_t a) { 11*0b57cec5SDimitry Andric 12*0b57cec5SDimitry Andric static const double twop32 = 0x1.0p32; 13*0b57cec5SDimitry Andric static const double twop52 = 0x1.0p52; 14*0b57cec5SDimitry Andric 15*0b57cec5SDimitry Andric doublebits low = {.d = twop52}; 16*0b57cec5SDimitry Andric low.x |= a & UINT64_C(0x00000000ffffffff); // 0x1.0p52 + low 32 bits of a. 17*0b57cec5SDimitry Andric 18*0b57cec5SDimitry Andric const double high_addend = (double)((int32_t)(a >> 32)) * twop32 - twop52; 19*0b57cec5SDimitry Andric 20*0b57cec5SDimitry Andric // At this point, we have two double precision numbers 21*0b57cec5SDimitry Andric // high_addend and low.d, and we wish to return their sum 22*0b57cec5SDimitry Andric // as a canonicalized long double: 23*0b57cec5SDimitry Andric 24*0b57cec5SDimitry Andric // This implementation sets the inexact flag spuriously. 25*0b57cec5SDimitry Andric // This could be avoided, but at some substantial cost. 26*0b57cec5SDimitry Andric 27*0b57cec5SDimitry Andric DD result; 28*0b57cec5SDimitry Andric 29*0b57cec5SDimitry Andric result.s.hi = high_addend + low.d; 30*0b57cec5SDimitry Andric result.s.lo = (high_addend - result.s.hi) + low.d; 31*0b57cec5SDimitry Andric 32*0b57cec5SDimitry Andric return result.ld; 33*0b57cec5SDimitry Andric } 34