1*3cab2bb3Spatrick // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 2*3cab2bb3Spatrick // See https://llvm.org/LICENSE.txt for license information. 3*3cab2bb3Spatrick // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 4*3cab2bb3Spatrick 5*3cab2bb3Spatrick // long double __floatditf(long long x); 6*3cab2bb3Spatrick // This file implements the PowerPC long long -> long double conversion 7*3cab2bb3Spatrick 8*3cab2bb3Spatrick #include "DD.h" 9*3cab2bb3Spatrick __floatditf(int64_t a)10*3cab2bb3Spatricklong double __floatditf(int64_t a) { 11*3cab2bb3Spatrick 12*3cab2bb3Spatrick static const double twop32 = 0x1.0p32; 13*3cab2bb3Spatrick static const double twop52 = 0x1.0p52; 14*3cab2bb3Spatrick 15*3cab2bb3Spatrick doublebits low = {.d = twop52}; 16*3cab2bb3Spatrick low.x |= a & UINT64_C(0x00000000ffffffff); // 0x1.0p52 + low 32 bits of a. 17*3cab2bb3Spatrick 18*3cab2bb3Spatrick const double high_addend = (double)((int32_t)(a >> 32)) * twop32 - twop52; 19*3cab2bb3Spatrick 20*3cab2bb3Spatrick // At this point, we have two double precision numbers 21*3cab2bb3Spatrick // high_addend and low.d, and we wish to return their sum 22*3cab2bb3Spatrick // as a canonicalized long double: 23*3cab2bb3Spatrick 24*3cab2bb3Spatrick // This implementation sets the inexact flag spuriously. 25*3cab2bb3Spatrick // This could be avoided, but at some substantial cost. 26*3cab2bb3Spatrick 27*3cab2bb3Spatrick DD result; 28*3cab2bb3Spatrick 29*3cab2bb3Spatrick result.s.hi = high_addend + low.d; 30*3cab2bb3Spatrick result.s.lo = (high_addend - result.s.hi) + low.d; 31*3cab2bb3Spatrick 32*3cab2bb3Spatrick return result.ld; 33*3cab2bb3Spatrick } 34