1/* This file is distributed under the University of Illinois Open Source
2 * License. See LICENSE.TXT for details.
3 */
4
5/* long double __gcc_qdiv(long double x, long double y);
6 * This file implements the PowerPC 128-bit double-double division operation.
7 * This implementation is shamelessly cribbed from Apple's DDRT, circa 1993(!)
8 */
9
10#include "DD.h"
11
12long double __gcc_qdiv(long double a, long double b)
13{
14	static const uint32_t infinityHi = UINT32_C(0x7ff00000);
15	DD dst = { .ld = a }, src = { .ld = b };
16
17	register double x = dst.s.hi, x1 = dst.s.lo,
18					y = src.s.hi, y1 = src.s.lo;
19
20    double yHi, yLo, qHi, qLo;
21    double yq, tmp, q;
22
23    q = x / y;
24
25	/* Detect special cases */
26	if (q == 0.0) {
27		dst.s.hi = q;
28		dst.s.lo = 0.0;
29		return dst.ld;
30	}
31
32	const doublebits qBits = { .d = q };
33	if (((uint32_t)(qBits.x >> 32) & infinityHi) == infinityHi) {
34		dst.s.hi = q;
35		dst.s.lo = 0.0;
36		return dst.ld;
37	}
38
39    yHi = high26bits(y);
40    qHi = high26bits(q);
41
42    yq = y * q;
43    yLo = y - yHi;
44    qLo = q - qHi;
45
46    tmp = LOWORDER(yq, yHi, yLo, qHi, qLo);
47    tmp = (x - yq) - tmp;
48    tmp = ((tmp + x1) - y1 * q) / y;
49    x = q + tmp;
50
51    dst.s.lo = (q - x) + tmp;
52    dst.s.hi = x;
53
54    return dst.ld;
55}
56