1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
|
/*
* A minimal 128-bit integer type for curve25519-donna
* (C) 2014 Jack Lloyd
*
* Botan is released under the Simplified BSD License (see license.txt)
*/
#ifndef BOTAN_CURVE25519_DONNA128_H_
#define BOTAN_CURVE25519_DONNA128_H_
#include <botan/mul128.h>
namespace Botan {
class donna128 final
{
public:
donna128(uint64_t ll = 0, uint64_t hh = 0) { l = ll; h = hh; }
donna128(const donna128&) = default;
donna128& operator=(const donna128&) = default;
friend donna128 operator>>(const donna128& x, size_t shift)
{
donna128 z = x;
if(shift > 0)
{
const uint64_t carry = z.h << (64 - shift);
z.h = (z.h >> shift);
z.l = (z.l >> shift) | carry;
}
return z;
}
friend donna128 operator<<(const donna128& x, size_t shift)
{
donna128 z = x;
if(shift > 0)
{
const uint64_t carry = z.l >> (64 - shift);
z.l = (z.l << shift);
z.h = (z.h << shift) | carry;
}
return z;
}
friend uint64_t operator&(const donna128& x, uint64_t mask)
{
return x.l & mask;
}
uint64_t operator&=(uint64_t mask)
{
h = 0;
l &= mask;
return l;
}
donna128& operator+=(const donna128& x)
{
l += x.l;
h += x.h;
const uint64_t carry = (l < x.l);
h += carry;
return *this;
}
donna128& operator+=(uint64_t x)
{
l += x;
const uint64_t carry = (l < x);
h += carry;
return *this;
}
uint64_t lo() const { return l; }
uint64_t hi() const { return h; }
private:
uint64_t h = 0, l = 0;
};
inline donna128 operator*(const donna128& x, uint64_t y)
{
BOTAN_ARG_CHECK(x.hi() == 0, "High 64 bits of donna128 set to zero during multiply");
uint64_t lo = 0, hi = 0;
mul64x64_128(x.lo(), y, &lo, &hi);
return donna128(lo, hi);
}
inline donna128 operator*(uint64_t y, const donna128& x)
{
return x * y;
}
inline donna128 operator+(const donna128& x, const donna128& y)
{
donna128 z = x;
z += y;
return z;
}
inline donna128 operator+(const donna128& x, uint64_t y)
{
donna128 z = x;
z += y;
return z;
}
inline donna128 operator|(const donna128& x, const donna128& y)
{
return donna128(x.lo() | y.lo(), x.hi() | y.hi());
}
inline uint64_t carry_shift(const donna128& a, size_t shift)
{
return (a >> shift).lo();
}
inline uint64_t combine_lower(const donna128& a, size_t s1,
const donna128& b, size_t s2)
{
donna128 z = (a >> s1) | (b << s2);
return z.lo();
}
#if defined(BOTAN_TARGET_HAS_NATIVE_UINT128)
inline uint64_t carry_shift(const uint128_t a, size_t shift)
{
return static_cast<uint64_t>(a >> shift);
}
inline uint64_t combine_lower(const uint128_t a, size_t s1,
const uint128_t b, size_t s2)
{
return static_cast<uint64_t>((a >> s1) | (b << s2));
}
#endif
}
#endif
|
