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Numeric Limits

amounts

uint112

Maximum sane amount (result of balanceOf) for external tokens

Uniswap2 limits token amounts to this

Spec: For an 18 decimal token, more than a million billion tokens (1e15)

small amounts

uint96

For holding amounts that we don't expect to get quite as large, in particular reserve balances

Can pack together with an address in a single slot

Spec: For an 18 decimal token, more than a billion tokens (1e9)

debt amounts

uint144

Maximum sane amount for debts

Packs together with an amount in a single storage slot

Spec: Should hold the maximum possible amount (uint112) but scaled by another 9 decimal places (for the internal debt precision)

Actual: 2e16

prices

Minimum supported price:

Fraction: 1e3 / 1e18 = 1e-15

Tick: -345405

sqrtPriceX96: 2505418623681149822473

Maximum supported price:

Fraction: 1e33 / 1e18 = 1e15

Tick: 345405

sqrtPriceX96: 2505410343826649584586222772852783278

The supported price range was chosen for the following reason:

The maximum price squared fits in a uint256: 6e73 < 1e77

Not necessary to use FullMath library

The maximum supported price times the maximum supported amount fits within a uint256: 5e66 < 1e77

Also holds with debt and its extra 9 digits of precision: 5e75 < 1e77

interestRate

int96

"Second Percent Yield"

Fraction scaled by 1e27

Example: 10% APR = 1e27 * 0.1 / (86400*365) = 1e27 * 0.000000003170979198376458650 = 3170979198376458650

Spec: 1 billion % APR, positive or negative

interestAccumulator

uint256

Starts at 1e27, multiplied by (1e27 + interestRate) every second

Spec: 100% APR for 100 years

1

-> 2^256

2

~= 1.1579208923e+77

3

-> 10^27 * (1 + (100/100 / (86400*365)))^(86400*365*100)

4

~= 2.6881128798e+70

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moduleId

uint32

One per module, so this is way more than needed

Divided into 3 sections

<500_000: Public single-proxy

=500_000 and <1_000_000: Public multi-proxy

=1_000_000: Internal

Spec: A dozen or so modules, with room to grow in all sections

collateralFactor/borrowFactor

uint32

Fraction between 0 and 1, scaled by 2^32 - 1

Spec: At least 3 decimal places (overkill)

Last modified 3mo ago

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