/
TickMath.sol
205 lines (190 loc) · 8.44 KB
/
TickMath.sol
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
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
// SPDX-License-Identifier: GPL-2.0-or-later
pragma solidity >=0.5.0 <0.8.0;
/// @title Math library for computing sqrt prices from ticks and vice versa
/// @notice Computes sqrt price for ticks of size 1.0001, i.e. sqrt(1.0001^tick) as fixed point Q64.96 numbers. Supports
/// prices between 2**-128 and 2**128
library TickMath {
/// @dev The minimum tick that may be passed to #getSqrtRatioAtTick computed from log base 1.0001 of 2**-128
int24 internal constant MIN_TICK = -887272;
/// @dev The maximum tick that may be passed to #getSqrtRatioAtTick computed from log base 1.0001 of 2**128
int24 internal constant MAX_TICK = -MIN_TICK;
/// @dev The minimum value that can be returned from #getSqrtRatioAtTick. Equivalent to getSqrtRatioAtTick(MIN_TICK)
uint160 internal constant MIN_SQRT_RATIO = 4295128739;
/// @dev The maximum value that can be returned from #getSqrtRatioAtTick. Equivalent to getSqrtRatioAtTick(MAX_TICK)
uint160 internal constant MAX_SQRT_RATIO = 1461446703485210103287273052203988822378723970342;
/// @notice Calculates sqrt(1.0001^tick) * 2^96
/// @dev Throws if |tick| > max tick
/// @param tick The input tick for the above formula
/// @return sqrtPriceX96 A Fixed point Q64.96 number representing the sqrt of the ratio of the two assets (token1/token0)
/// at the given tick
function getSqrtRatioAtTick(int24 tick) internal pure returns (uint160 sqrtPriceX96) {
uint256 absTick = tick < 0 ? uint256(-int256(tick)) : uint256(int256(tick));
require(absTick <= uint256(MAX_TICK), 'T');
uint256 ratio = absTick & 0x1 != 0 ? 0xfffcb933bd6fad37aa2d162d1a594001 : 0x100000000000000000000000000000000;
if (absTick & 0x2 != 0) ratio = (ratio * 0xfff97272373d413259a46990580e213a) >> 128;
if (absTick & 0x4 != 0) ratio = (ratio * 0xfff2e50f5f656932ef12357cf3c7fdcc) >> 128;
if (absTick & 0x8 != 0) ratio = (ratio * 0xffe5caca7e10e4e61c3624eaa0941cd0) >> 128;
if (absTick & 0x10 != 0) ratio = (ratio * 0xffcb9843d60f6159c9db58835c926644) >> 128;
if (absTick & 0x20 != 0) ratio = (ratio * 0xff973b41fa98c081472e6896dfb254c0) >> 128;
if (absTick & 0x40 != 0) ratio = (ratio * 0xff2ea16466c96a3843ec78b326b52861) >> 128;
if (absTick & 0x80 != 0) ratio = (ratio * 0xfe5dee046a99a2a811c461f1969c3053) >> 128;
if (absTick & 0x100 != 0) ratio = (ratio * 0xfcbe86c7900a88aedcffc83b479aa3a4) >> 128;
if (absTick & 0x200 != 0) ratio = (ratio * 0xf987a7253ac413176f2b074cf7815e54) >> 128;
if (absTick & 0x400 != 0) ratio = (ratio * 0xf3392b0822b70005940c7a398e4b70f3) >> 128;
if (absTick & 0x800 != 0) ratio = (ratio * 0xe7159475a2c29b7443b29c7fa6e889d9) >> 128;
if (absTick & 0x1000 != 0) ratio = (ratio * 0xd097f3bdfd2022b8845ad8f792aa5825) >> 128;
if (absTick & 0x2000 != 0) ratio = (ratio * 0xa9f746462d870fdf8a65dc1f90e061e5) >> 128;
if (absTick & 0x4000 != 0) ratio = (ratio * 0x70d869a156d2a1b890bb3df62baf32f7) >> 128;
if (absTick & 0x8000 != 0) ratio = (ratio * 0x31be135f97d08fd981231505542fcfa6) >> 128;
if (absTick & 0x10000 != 0) ratio = (ratio * 0x9aa508b5b7a84e1c677de54f3e99bc9) >> 128;
if (absTick & 0x20000 != 0) ratio = (ratio * 0x5d6af8dedb81196699c329225ee604) >> 128;
if (absTick & 0x40000 != 0) ratio = (ratio * 0x2216e584f5fa1ea926041bedfe98) >> 128;
if (absTick & 0x80000 != 0) ratio = (ratio * 0x48a170391f7dc42444e8fa2) >> 128;
if (tick > 0) ratio = type(uint256).max / ratio;
// this divides by 1<<32 rounding up to go from a Q128.128 to a Q128.96.
// we then downcast because we know the result always fits within 160 bits due to our tick input constraint
// we round up in the division so getTickAtSqrtRatio of the output price is always consistent
sqrtPriceX96 = uint160((ratio >> 32) + (ratio % (1 << 32) == 0 ? 0 : 1));
}
/// @notice Calculates the greatest tick value such that getRatioAtTick(tick) <= ratio
/// @dev Throws in case sqrtPriceX96 < MIN_SQRT_RATIO, as MIN_SQRT_RATIO is the lowest value getRatioAtTick may
/// ever return.
/// @param sqrtPriceX96 The sqrt ratio for which to compute the tick as a Q64.96
/// @return tick The greatest tick for which the ratio is less than or equal to the input ratio
function getTickAtSqrtRatio(uint160 sqrtPriceX96) internal pure returns (int24 tick) {
// second inequality must be < because the price can never reach the price at the max tick
require(sqrtPriceX96 >= MIN_SQRT_RATIO && sqrtPriceX96 < MAX_SQRT_RATIO, 'R');
uint256 ratio = uint256(sqrtPriceX96) << 32;
uint256 r = ratio;
uint256 msb = 0;
assembly {
let f := shl(7, gt(r, 0xFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF))
msb := or(msb, f)
r := shr(f, r)
}
assembly {
let f := shl(6, gt(r, 0xFFFFFFFFFFFFFFFF))
msb := or(msb, f)
r := shr(f, r)
}
assembly {
let f := shl(5, gt(r, 0xFFFFFFFF))
msb := or(msb, f)
r := shr(f, r)
}
assembly {
let f := shl(4, gt(r, 0xFFFF))
msb := or(msb, f)
r := shr(f, r)
}
assembly {
let f := shl(3, gt(r, 0xFF))
msb := or(msb, f)
r := shr(f, r)
}
assembly {
let f := shl(2, gt(r, 0xF))
msb := or(msb, f)
r := shr(f, r)
}
assembly {
let f := shl(1, gt(r, 0x3))
msb := or(msb, f)
r := shr(f, r)
}
assembly {
let f := gt(r, 0x1)
msb := or(msb, f)
}
if (msb >= 128) r = ratio >> (msb - 127);
else r = ratio << (127 - msb);
int256 log_2 = (int256(msb) - 128) << 64;
assembly {
r := shr(127, mul(r, r))
let f := shr(128, r)
log_2 := or(log_2, shl(63, f))
r := shr(f, r)
}
assembly {
r := shr(127, mul(r, r))
let f := shr(128, r)
log_2 := or(log_2, shl(62, f))
r := shr(f, r)
}
assembly {
r := shr(127, mul(r, r))
let f := shr(128, r)
log_2 := or(log_2, shl(61, f))
r := shr(f, r)
}
assembly {
r := shr(127, mul(r, r))
let f := shr(128, r)
log_2 := or(log_2, shl(60, f))
r := shr(f, r)
}
assembly {
r := shr(127, mul(r, r))
let f := shr(128, r)
log_2 := or(log_2, shl(59, f))
r := shr(f, r)
}
assembly {
r := shr(127, mul(r, r))
let f := shr(128, r)
log_2 := or(log_2, shl(58, f))
r := shr(f, r)
}
assembly {
r := shr(127, mul(r, r))
let f := shr(128, r)
log_2 := or(log_2, shl(57, f))
r := shr(f, r)
}
assembly {
r := shr(127, mul(r, r))
let f := shr(128, r)
log_2 := or(log_2, shl(56, f))
r := shr(f, r)
}
assembly {
r := shr(127, mul(r, r))
let f := shr(128, r)
log_2 := or(log_2, shl(55, f))
r := shr(f, r)
}
assembly {
r := shr(127, mul(r, r))
let f := shr(128, r)
log_2 := or(log_2, shl(54, f))
r := shr(f, r)
}
assembly {
r := shr(127, mul(r, r))
let f := shr(128, r)
log_2 := or(log_2, shl(53, f))
r := shr(f, r)
}
assembly {
r := shr(127, mul(r, r))
let f := shr(128, r)
log_2 := or(log_2, shl(52, f))
r := shr(f, r)
}
assembly {
r := shr(127, mul(r, r))
let f := shr(128, r)
log_2 := or(log_2, shl(51, f))
r := shr(f, r)
}
assembly {
r := shr(127, mul(r, r))
let f := shr(128, r)
log_2 := or(log_2, shl(50, f))
}
int256 log_sqrt10001 = log_2 * 255738958999603826347141; // 128.128 number
int24 tickLow = int24((log_sqrt10001 - 3402992956809132418596140100660247210) >> 128);
int24 tickHi = int24((log_sqrt10001 + 291339464771989622907027621153398088495) >> 128);
tick = tickLow == tickHi ? tickLow : getSqrtRatioAtTick(tickHi) <= sqrtPriceX96 ? tickHi : tickLow;
}
}