1*156cd587Sjoerg /* This file is distributed under the University of Illinois Open Source 2*156cd587Sjoerg * License. See LICENSE.TXT for details. 3*156cd587Sjoerg */ 4*156cd587Sjoerg 5*156cd587Sjoerg /* long double __floatditf(long long x); */ 6*156cd587Sjoerg /* This file implements the PowerPC long long -> long double conversion */ 7*156cd587Sjoerg 8*156cd587Sjoerg #include "DD.h" 9*156cd587Sjoerg __floatditf(int64_t a)10*156cd587Sjoerglong double __floatditf(int64_t a) { 11*156cd587Sjoerg 12*156cd587Sjoerg static const double twop32 = 0x1.0p32; 13*156cd587Sjoerg static const double twop52 = 0x1.0p52; 14*156cd587Sjoerg 15*156cd587Sjoerg doublebits low = { .d = twop52 }; 16*156cd587Sjoerg low.x |= a & UINT64_C(0x00000000ffffffff); /* 0x1.0p52 + low 32 bits of a. */ 17*156cd587Sjoerg 18*156cd587Sjoerg const double high_addend = (double)((int32_t)(a >> 32))*twop32 - twop52; 19*156cd587Sjoerg 20*156cd587Sjoerg /* At this point, we have two double precision numbers 21*156cd587Sjoerg * high_addend and low.d, and we wish to return their sum 22*156cd587Sjoerg * as a canonicalized long double: 23*156cd587Sjoerg */ 24*156cd587Sjoerg 25*156cd587Sjoerg /* This implementation sets the inexact flag spuriously. 26*156cd587Sjoerg * This could be avoided, but at some substantial cost. 27*156cd587Sjoerg */ 28*156cd587Sjoerg 29*156cd587Sjoerg DD result; 30*156cd587Sjoerg 31*156cd587Sjoerg result.s.hi = high_addend + low.d; 32*156cd587Sjoerg result.s.lo = (high_addend - result.s.hi) + low.d; 33*156cd587Sjoerg 34*156cd587Sjoerg return result.ld; 35*156cd587Sjoerg 36*156cd587Sjoerg } 37