1 /* This file is distributed under the University of Illinois Open Source 2 * License. See LICENSE.TXT for details. 3 */ 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 25 /* This implementation sets the inexact flag spuriously. 26 * This could be avoided, but at some substantial cost. 27 */ 28 29 DD result; 30 31 result.s.hi = high_addend + low.d; 32 result.s.lo = (high_addend - result.s.hi) + low.d; 33 34 return result.ld; 35 36 } 37
