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// 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"
#include <stdint.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.hi = high_addend + low.d;
result.lo = (high_addend - result.hi) + low.d;
return result.ld;
}
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