xref: /openbmc/qemu/util/host-utils.c (revision 1fd6bb44)
1 /*
2  * Utility compute operations used by translated code.
3  *
4  * Copyright (c) 2003 Fabrice Bellard
5  * Copyright (c) 2007 Aurelien Jarno
6  *
7  * Permission is hereby granted, free of charge, to any person obtaining a copy
8  * of this software and associated documentation files (the "Software"), to deal
9  * in the Software without restriction, including without limitation the rights
10  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
11  * copies of the Software, and to permit persons to whom the Software is
12  * furnished to do so, subject to the following conditions:
13  *
14  * The above copyright notice and this permission notice shall be included in
15  * all copies or substantial portions of the Software.
16  *
17  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
18  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
19  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
20  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
21  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
22  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
23  * THE SOFTWARE.
24  */
25 
26 #include <stdlib.h>
27 #include <stdint.h>
28 #include "qemu/host-utils.h"
29 
30 /* Long integer helpers */
31 #ifndef CONFIG_INT128
32 static inline void mul64(uint64_t *plow, uint64_t *phigh,
33                          uint64_t a, uint64_t b)
34 {
35     typedef union {
36         uint64_t ll;
37         struct {
38 #ifdef HOST_WORDS_BIGENDIAN
39             uint32_t high, low;
40 #else
41             uint32_t low, high;
42 #endif
43         } l;
44     } LL;
45     LL rl, rm, rn, rh, a0, b0;
46     uint64_t c;
47 
48     a0.ll = a;
49     b0.ll = b;
50 
51     rl.ll = (uint64_t)a0.l.low * b0.l.low;
52     rm.ll = (uint64_t)a0.l.low * b0.l.high;
53     rn.ll = (uint64_t)a0.l.high * b0.l.low;
54     rh.ll = (uint64_t)a0.l.high * b0.l.high;
55 
56     c = (uint64_t)rl.l.high + rm.l.low + rn.l.low;
57     rl.l.high = c;
58     c >>= 32;
59     c = c + rm.l.high + rn.l.high + rh.l.low;
60     rh.l.low = c;
61     rh.l.high += (uint32_t)(c >> 32);
62 
63     *plow = rl.ll;
64     *phigh = rh.ll;
65 }
66 
67 /* Unsigned 64x64 -> 128 multiplication */
68 void mulu64 (uint64_t *plow, uint64_t *phigh, uint64_t a, uint64_t b)
69 {
70     mul64(plow, phigh, a, b);
71 }
72 
73 /* Signed 64x64 -> 128 multiplication */
74 void muls64 (uint64_t *plow, uint64_t *phigh, int64_t a, int64_t b)
75 {
76     uint64_t rh;
77 
78     mul64(plow, &rh, a, b);
79 
80     /* Adjust for signs.  */
81     if (b < 0) {
82         rh -= a;
83     }
84     if (a < 0) {
85         rh -= b;
86     }
87     *phigh = rh;
88 }
89 #endif /* !CONFIG_INT128 */
90