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util_uint128.h
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1 /*
2  * Copyright (c) 2015 Hugh Bailey <obs.jim@gmail.com>
3  *
4  * Permission to use, copy, modify, and distribute this software for any
5  * purpose with or without fee is hereby granted, provided that the above
6  * copyright notice and this permission notice appear in all copies.
7  *
8  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
9  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
10  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
11  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
12  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
13  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
14  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
15  */
16 
17 #pragma once
18 
19 struct util_uint128 {
20  union {
22  struct {
25  };
26  };
27 };
28 
30 
31 static inline util_uint128_t util_add128(util_uint128_t a, util_uint128_t b)
32 {
33  util_uint128_t out;
34  uint64_t val;
35 
36  val = (a.low & 0xFFFFFFFFULL) + (b.low & 0xFFFFFFFFULL);
37  out.i32[0] = (uint32_t)(val & 0xFFFFFFFFULL);
38  val >>= 32;
39 
40  val += (a.low >> 32) + (b.low >> 32);
41  out.i32[1] = (uint32_t)val;
42  val >>= 32;
43 
44  val += (a.high & 0xFFFFFFFFULL) + (b.high & 0xFFFFFFFFULL);
45  out.i32[2] = (uint32_t)(val & 0xFFFFFFFFULL);
46  val >>= 32;
47 
48  val += (a.high >> 32) + (b.high >> 32);
49  out.i32[3] = (uint32_t)val;
50 
51  return out;
52 }
53 
54 static inline util_uint128_t util_lshift64(uint64_t a, int num)
55 {
56  util_uint128_t val;
57  val.low = a << num;
58  val.high = a >> (64 - num);
59  return val;
60 }
61 
62 static inline util_uint128_t util_mul64_64(uint64_t a, uint64_t b)
63 {
64  util_uint128_t out;
65  uint64_t m;
66 
67  m = (a & 0xFFFFFFFFULL) * (b & 0xFFFFFFFFULL);
68  out.low = m;
69  out.high = 0;
70 
71  m = (a >> 32) * (b & 0xFFFFFFFFULL);
72  out = util_add128(out, util_lshift64(m, 32));
73 
74  m = (a & 0xFFFFFFFFULL) * (b >> 32);
75  out = util_add128(out, util_lshift64(m, 32));
76 
77  m = (a >> 32) * (b >> 32);
78  out = util_add128(out, util_lshift64(m, 64));
79 
80  return out;
81 }
82 
83 static inline util_uint128_t util_div128_32(util_uint128_t a, uint32_t b)
84 {
85  util_uint128_t out;
86  uint64_t val = 0;
87 
88  for (int i = 3; i >= 0; i--) {
89  val = (val << 32) | a.i32[i];
90  if (val < b) {
91  out.i32[i] = 0;
92  continue;
93  }
94 
95  out.i32[i] = (uint32_t)(val / b);
96  val = val % b;
97  }
98 
99  return out;
100 }
Definition: util_uint128.h:19
uint64_t high
Definition: util_uint128.h:24
uint32_t i32[4]
Definition: util_uint128.h:21
unsigned uint32_t
Definition: vc_stdint.h:31
unsigned __int64 uint64_t
Definition: vc_stdint.h:33
uint64_t low
Definition: util_uint128.h:23