| /* This file is distributed under the University of Illinois Open Source |
| * License. See LICENSE.TXT for details. |
| */ |
| |
| /* 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; |
| |
| } |
