dToken rounding and gas golfing

dtoken rounding
TempleDAO · Aug 14, 2023 · e0464a6 · e0464a6
1 parent 81553f6
commit e0464a6
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Showing 9 changed files with 293 additions and 246 deletions.
diff --git a/protocol/contracts/interfaces/v2/ITempleDebtToken.sol b/protocol/contracts/interfaces/v2/ITempleDebtToken.sol
@@ -27,19 +27,33 @@ interface ITempleDebtToken is IERC20, IERC20Metadata, ITempleElevatedAccess {
     function baseRate() external view returns (uint96);
 
     /**
-     * @notice The (base rate) total number of shares allocated out to users for internal book keeping
+     * @notice The last checkpoint time of the (base rate) principal and interest checkpoint
      */
-    function baseShares() external view returns (uint256);
+    function baseCheckpointTime() external view returns (uint32);
 
     /**
      * @notice The (base rate) total principal and interest owed across all debtors as of the latest checkpoint
      */
-    function baseCheckpoint() external view returns (uint256);
+    function baseCheckpoint() external view returns (uint128);
 
     /**
-     * @notice The last checkpoint time of the (base rate) principal and interest checkpoint
+     * @notice The (base rate) total number of shares allocated out to users for internal book keeping
      */
-    function baseCheckpointTime() external view returns (uint32);
+    function baseShares() external view returns (uint128);
+
+    /**
+     * @notice The net amount of principal amount of debt minted across all users.
+     */
+    function totalPrincipal() external view returns (uint128);
+
+    /**
+     * @notice The latest estimate of the (risk premium) interest (no principal) owed.
+     * @dev Indicative only. This total is only updated on a per strategy basis when that strategy gets 
+     * checkpointed (on borrow/repay rate change).
+     * So it is generally always going to be out of date as each strategy will accrue interest independently 
+     * on different rates.
+     */
+    function estimatedTotalRiskPremiumInterest() external view returns (uint128);
 
     /// @dev byte packed into two slots.
     struct Debtor {
@@ -82,20 +96,6 @@ interface ITempleDebtToken is IERC20, IERC20Metadata, ITempleElevatedAccess {
         uint32 checkpointTime
     );
 
-    /**
-     * @notice The net amount of principal amount of debt minted across all users.
-     */
-    function totalPrincipal() external view returns (uint256);
-
-    /**
-     * @notice The latest estimate of the (risk premium) interest (no principal) owed.
-     * @dev Indicative only. This total is only updated on a per strategy basis when that strategy gets 
-     * checkpointed (on borrow/repay rate change).
-     * So it is generally always going to be out of date as each strategy will accrue interest independently 
-     * on different rates.
-     */
-    function estimatedTotalRiskPremiumInterest() external view returns (uint256);
-
     /// @notice A set of addresses which are approved to mint/burn
     function minters(address account) external view returns (bool);
 
@@ -200,10 +200,10 @@ interface ITempleDebtToken is IERC20, IERC20Metadata, ITempleElevatedAccess {
     /**
      * @notice Convert a (base interest) debt amount into proportional amount of shares
      */
-    function baseDebtToShares(uint256 debt) external view returns (uint256);
+    function baseDebtToShares(uint128 debt) external view returns (uint128);
 
     /**
      * @notice Convert a number of (base interest) shares into proportional amount of debt
      */
-    function baseSharesToDebt(uint256 shares) external view returns (uint256);
+    function baseSharesToDebt(uint128 shares) external view returns (uint128);
 }
diff --git a/protocol/contracts/v2/TempleDebtToken.sol b/protocol/contracts/v2/TempleDebtToken.sol
diff --git a/protocol/contracts/v2/templeLineOfCredit/TempleLineOfCredit.sol b/protocol/contracts/v2/templeLineOfCredit/TempleLineOfCredit.sol
@@ -222,7 +222,7 @@ contract TempleLineOfCredit is ITempleLineOfCredit, TempleElevatedAccess {
                 _cache, 
                 _accountData.debtCheckpoint, 
                 _accountData.interestAccumulator,
-                false // don't round on the way in
+                false // don't round up on the way in
             ) + amount;
 
             // Update the state
@@ -633,7 +633,7 @@ contract TempleLineOfCredit is ITempleLineOfCredit, TempleElevatedAccess {
         }
 
         // Only compound if we're on a new block
-        uint256 interestAccumulatorUpdatedAt = debtTokenData.interestAccumulatorUpdatedAt;
+        uint32 interestAccumulatorUpdatedAt = debtTokenData.interestAccumulatorUpdatedAt;
         uint32 blockTs = uint32(block.timestamp);
         if (blockTs != interestAccumulatorUpdatedAt) {
             dirty = true;

diff --git a/protocol/test/forge/v2/templeDebtToken/TempleDebtToken.Base.t.sol b/protocol/test/forge/v2/templeDebtToken/TempleDebtToken.Base.t.sol
@@ -142,13 +142,14 @@ contract TempleDebtTokenTestBase is TempleTest {
     function makeExpected(
         uint256 baseShares, 
         uint256 baseTotal, 
-        uint256 debtorInterestOnly
+        uint256 debtorInterestOnly,
+        bool roundUp
     ) internal pure returns (Expected memory) {
         return Expected({
             baseShares: baseShares,
             baseTotal: baseTotal,
             debtorInterestOnly: debtorInterestOnly,
-            balanceOf: baseTotal + debtorInterestOnly
+            balanceOf: baseTotal + debtorInterestOnly + (roundUp ? 1 : 0)
         });
     }
 }