1 // SPDX-License-Identifier: GPL-2.0-only
2 /* IEEE754 floating point arithmetic
3 * double precision: common utilities
4 */
5 /*
6 * MIPS floating point support
7 * Copyright (C) 1994-2000 Algorithmics Ltd.
8 */
9
10 #include "ieee754dp.h"
11
12 union ieee754dp ieee754dp_flong(s64 x)
13 {
14 u64 xm;
15 int xe;
16 int xs;
17
18 ieee754_clearcx();
19
20 if (x == 0)
21 return ieee754dp_zero(0);
22 if (x == 1 || x == -1)
23 return ieee754dp_one(x < 0);
24 if (x == 10 || x == -10)
25 return ieee754dp_ten(x < 0);
26
27 xs = (x < 0);
28 if (xs) {
29 if (x == (1ULL << 63))
30 xm = (1ULL << 63); /* max neg can't be safely negated */
31 else
32 xm = -x;
33 } else {
34 xm = x;
35 }
36
37 /* normalize */
38 xe = DP_FBITS + 3;
39 if (xm >> (DP_FBITS + 1 + 3)) {
40 /* shunt out overflow bits */
41 while (xm >> (DP_FBITS + 1 + 3)) {
42 XDPSRSX1();
43 }
44 } else {
45 /* normalize in grs extended double precision */
46 while ((xm >> (DP_FBITS + 3)) == 0) {
47 xm <<= 1;
48 xe--;
49 }
50 }
51
52 return ieee754dp_format(xs, xe, xm);
53 }
54
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