1214152Sed/* This file is distributed under the University of Illinois Open Source
2214152Sed * License. See LICENSE.TXT for details.
3214152Sed */
4214152Sed
5214152Sed/* long double __floatditf(long long x); */
6214152Sed/* This file implements the PowerPC long long -> long double conversion */
7214152Sed
8214152Sed#include "DD.h"
9214152Sed
10214152Sedlong double __floatditf(int64_t a) {
11214152Sed
12214152Sed	static const double twop32 = 0x1.0p32;
13214152Sed	static const double twop52 = 0x1.0p52;
14214152Sed
15214152Sed	doublebits low  = { .d = twop52 };
16214152Sed	low.x |= a & UINT64_C(0x00000000ffffffff);	/* 0x1.0p52 + low 32 bits of a. */
17214152Sed
18214152Sed	const double high_addend = (double)((int32_t)(a >> 32))*twop32 - twop52;
19214152Sed
20214152Sed	/* At this point, we have two double precision numbers
21214152Sed	 * high_addend and low.d, and we wish to return their sum
22214152Sed	 * as a canonicalized long double:
23214152Sed	 */
24214152Sed
25214152Sed	/* This implementation sets the inexact flag spuriously.
26214152Sed	 * This could be avoided, but at some substantial cost.
27214152Sed	*/
28214152Sed
29214152Sed	DD result;
30214152Sed
31214152Sed	result.s.hi = high_addend + low.d;
32214152Sed	result.s.lo = (high_addend - result.s.hi) + low.d;
33214152Sed
34214152Sed	return result.ld;
35214152Sed
36214152Sed}
37