WIP: Chore(evm) add combine pricefeed

target_chains/ethereum/contracts/forge-test/utils/PythTestUtils.t.sol

@@ -370,25 +370,50 @@ abstract contract PythTestUtils is Test, WormholeTestUtils, RandTestUtils {
 }
 
 contract PythUtilsTest is Test, WormholeTestUtils, PythTestUtils, IPythEvents {
+    function assertCrossRateEquals(
+        int64 price1, 
+        int32 expo1, 
+        int64 price2, 
+        int32 expo2,
+        int32 targetExpo, 
+        int64 expectedPrice
+    ) internal {
+        int64 price = PythUtils.deriveCrossRate(price1, expo1, price2, expo2, targetExpo);
+        assertEq(price, expectedPrice);
+    }
+
+    function assertCrossRateReverts(
+        int64 price1, 
+        int32 expo1, 
+        int64 price2, 
+        int32 expo2,
+        int32 targetExpo,
+        bytes4 expectedError
+    ) internal {
+        vm.expectRevert(expectedError);
+        PythUtils.deriveCrossRate(price1, expo1, price2, expo2, targetExpo);
+    }
+
     function testConvertToUnit() public {
         // Price can't be negative
-        vm.expectRevert();
+        vm.expectRevert(PythErrors.NegativeInputPrice.selector);
         PythUtils.convertToUint(-100, -5, 18);
 
-        // Exponent can't be positive
-        vm.expectRevert();
-        PythUtils.convertToUint(100, 5, 18);
+        // Exponent can't be less than -255
+        vm.expectRevert(PythErrors.InvalidInputExpo.selector);
+        PythUtils.convertToUint(100, -256, 18);
 
+        // Negative Exponent Tests
         // Price with 18 decimals and exponent -5
         assertEq(
             PythUtils.convertToUint(100, -5, 18),
-            1000000000000000 // 100 * 10^13
+            100_0_000_000_000_000 // 100 * 10^13
         );
 
         // Price with 9 decimals and exponent -2
         assertEq(
             PythUtils.convertToUint(100, -2, 9),
-            1000000000 // 100 * 10^7
+            100_0_000_000 // 100 * 10^7
         );
 
         // Price with 4 decimals and exponent -5
@@ -398,5 +423,72 @@ contract PythUtilsTest is Test, WormholeTestUtils, PythTestUtils, IPythEvents {
         // @note: We will lose precision here as price is
         // 0.00001 and we are targetDecimals is 2.
         assertEq(PythUtils.convertToUint(100, -5, 2), 0);
+
+        assertEq(PythUtils.convertToUint(123, -8, 5), 0);
+
+        // Positive Exponent Tests
+        // Price with 18 decimals and exponent 5
+        assertEq(PythUtils.convertToUint(100, 5, 18), 100_00_000_000_000_000_000_000_000); // 100 with23 zeros
+
+        // Price with 9 decimals and exponent 2
+        assertEq(PythUtils.convertToUint(100, 2, 9), 100_00_000_000_000); // 100 with 11 zeros
+
+        // Price with 4 decimals and exponent 5
+        assertEq(PythUtils.convertToUint(100, 1, 2), 100_000); // 100 with 3 zeros  
+
+
+        // Edge Cases
+        // This test will fail as the 10 ** 237 is too large for a uint256
+        // assertEq(PythUtils.convertToUint(100, -255, 18), 0);
+        // assertEq(PythUtils.convertToUint(100, 255, 18), 100_00_000_000_000_000_000_000_000);
+    }
+
+    function testCombinePrices() public {
+
+        // Basic Tests 
+        assertCrossRateEquals(500, -8, 500, -8, -5, 100000); 
+        assertCrossRateEquals(10_000, -8, 100, -2, -5, 10);
+        assertCrossRateEquals(10_000, -2, 100, -8, -4, 1_000_000_000_000);
+
+        // Negative Price Tests
+        assertCrossRateReverts(-100, -2, 100, -2, -5, PythErrors.NegativeInputPrice.selector);
+        assertCrossRateReverts(100, -2, -100, -2, -5, PythErrors.NegativeInputPrice.selector);
+        assertCrossRateReverts(-100, -2, -100, -2, -5, PythErrors.NegativeInputPrice.selector);
+
+        // Positive Exponent Tests
+        assertCrossRateReverts(100, 2, 100, -2, -5, PythErrors.InvalidInputExpo.selector);
+        assertCrossRateReverts(100, -2, 100, 2, -5, PythErrors.InvalidInputExpo.selector);
+        assertCrossRateReverts(100, 2, 100, 2, -5, PythErrors.InvalidInputExpo.selector);
+
+        // Invalid Target Exponent Tests
+        assertCrossRateReverts(100, -2, 100, -2, 1, PythErrors.InvalidTargetExpo.selector);
+
+        // Different Exponent Tests
+        assertCrossRateEquals(10_000, -2, 100, -4, -4, 100_000_000); 
+        assertCrossRateEquals(10_000, -2, 10_000, -1, -2, 10);
+        assertCrossRateEquals(10_000, -10, 10_000, -2, 0, 0); // It will truncate to 0
+
+        // Exponent Edge Tests
+        assertCrossRateEquals(10_000, 0, 100, 0, 0, 100); 
+        assertCrossRateEquals(10_000, 0, 100, 0, -255, 100); 
+        // assertCrossRateEquals(10_000, 0, 100, -255, -255, 100, -255); 
+        // assertCrossRateEquals(10_000, -255, 100, 0, 0, 100, 0); 
+
+        // // End Range Tests
+        // successTest(int64(type(int64).max), 0, int64(type(int64).max), 0, 1, 0);
+        // successTest(int64(type(int64).max), 0, 1, 0, int64(type(int64).max), 0);
+        // successTest(1, 0, int64(type(int64).max), 0, 1 / int64(type(int64).max), 0);
+        // revertTest(10_000, -2, 10_000, -256);
+
+        // // More Realistic Tests
+        // // Test case 1:  (StEth/Eth / Eth/USD = ETH/BTC)
+        // (int64 price, int32 expo) = PythUtils.deriveCrossRate(206487956502, -8, 206741615681, -8);
+        // assertApproxEqRel(price, 100000000, 9e17); // $1
+        // assertEq(expo, -8);
+
+        // // Test case 2: 
+        // (price, expo) = PythUtils.deriveCrossRate(520010, -8, 38591, -8);
+        // assertApproxEqRel(price, 1347490347, 9e17); // $1
+        // assertEq(expo, -8);
     }
 }

target_chains/ethereum/sdk/solidity/Math.sol

@@ -0,0 +1,208 @@
+// SPDX-License-Identifier: MIT
+// OpenZeppelin Contracts (last updated v5.3.0) (utils/math/Math.sol)
+// Source: https://github.com/OpenZeppelin/openzeppelin-contracts/blob/v5.3.0/contracts/utils/math/Math.sol
+
+
+pragma solidity ^0.8.0;
+
+library Math {
+
+    /// @dev division or modulo by zero
+    uint256 internal constant DIVISION_BY_ZERO = 0x12;
+    /// @dev arithmetic underflow or overflow
+    uint256 internal constant UNDER_OVERFLOW = 0x11;
+
+
+   /**
+     * @dev Return the 512-bit multiplication of two uint256.
+     *
+     * The result is stored in two 256 variables such that product = high * 2²⁵⁶ + low.
+     */
+    function mul512(uint256 a, uint256 b) internal pure returns (uint256 high, uint256 low) {
+        // 512-bit multiply [high low] = x * y. Compute the product mod 2²⁵⁶ and mod 2²⁵⁶ - 1, then use
+        // the Chinese Remainder Theorem to reconstruct the 512 bit result. The result is stored in two 256
+        // variables such that product = high * 2²⁵⁶ + low.
+        /// @solidity memory-safe-assembly
+        assembly {
+            let mm := mulmod(a, b, not(0))
+            low := mul(a, b)
+            high := sub(sub(mm, low), lt(mm, low))
+        }
+    }
+
+    /**
+     * @dev Branchless ternary evaluation for `a ? b : c`. Gas costs are constant.
+     *
+     * IMPORTANT: This function may reduce bytecode size and consume less gas when used standalone.
+     * However, the compiler may optimize Solidity ternary operations (i.e. `a ? b : c`) to only compute
+     * one branch when needed, making this function more expensive.
+     */
+    function ternary(bool condition, uint256 a, uint256 b) internal pure returns (uint256) {
+        unchecked {
+            // branchless ternary works because:
+            // b ^ (a ^ b) == a
+            // b ^ 0 == b
+            return b ^ ((a ^ b) * toUint(condition));
+        }
+    }
+
+    /**
+     * @dev Cast a boolean (false or true) to a uint256 (0 or 1) with no jump.
+     */
+    function toUint(bool b) internal pure returns (uint256 u) {
+        /// @solidity memory-safe-assembly
+        assembly {
+            u := iszero(iszero(b))
+        }
+    }
+
+    /// @dev Reverts with a panic code. Recommended to use with
+    /// the internal constants with predefined codes.
+    function panic(uint256 code) internal pure {
+        /// @solidity memory-safe-assembly
+        assembly {
+            mstore(0x00, 0x4e487b71)
+            mstore(0x20, code)
+            revert(0x1c, 0x24)
+        }
+    }
+
+
+    /**
+     * @dev Calculates floor(x * y / denominator) with full precision. Throws if result overflows a uint256 or
+     * denominator == 0.
+     *
+     * Original credit to Remco Bloemen under MIT license (https://xn--2-umb.com/21/muldiv) with further edits by
+     * Uniswap Labs also under MIT license.
+     */
+    function mulDiv(uint256 x, uint256 y, uint256 denominator) internal pure returns (uint256 result) {
+        unchecked {
+            (uint256 high, uint256 low) = mul512(x, y);
+
+            // Handle non-overflow cases, 256 by 256 division.
+            if (high == 0) {
+                // Solidity will revert if denominator == 0, unlike the div opcode on its own.
+                // The surrounding unchecked block does not change this fact.
+                // See https://docs.soliditylang.org/en/latest/control-structures.html#checked-or-unchecked-arithmetic.
+                return low / denominator;
+            }
+
+            // Make sure the result is less than 2²⁵⁶. Also prevents denominator == 0.
+            if (denominator <= high) {
+                panic(ternary(denominator == 0, DIVISION_BY_ZERO, UNDER_OVERFLOW));
+            }
+
+            ///////////////////////////////////////////////
+            // 512 by 256 division.
+            ///////////////////////////////////////////////
+
+            // Make division exact by subtracting the remainder from [high low].
+            uint256 remainder;
+            /// @solidity memory-safe-assembly
+            assembly {
+                // Compute remainder using mulmod.
+                remainder := mulmod(x, y, denominator)
+
+                // Subtract 256 bit number from 512 bit number.
+                high := sub(high, gt(remainder, low))
+                low := sub(low, remainder)
+            }
+
+            // Factor powers of two out of denominator and compute largest power of two divisor of denominator.
+            // Always >= 1. See https://cs.stackexchange.com/q/138556/92363.
+
+            uint256 twos = denominator & (0 - denominator);
+            /// @solidity memory-safe-assembly
+            assembly {
+                // Divide denominator by twos.
+                denominator := div(denominator, twos)
+
+                // Divide [high low] by twos.
+                low := div(low, twos)
+
+                // Flip twos such that it is 2²⁵⁶ / twos. If twos is zero, then it becomes one.
+                twos := add(div(sub(0, twos), twos), 1)
+            }
+
+            // Shift in bits from high into low.
+            low |= high * twos;
+
+            // Invert denominator mod 2²⁵⁶. Now that denominator is an odd number, it has an inverse modulo 2²⁵⁶ such
+            // that denominator * inv ≡ 1 mod 2²⁵⁶. Compute the inverse by starting with a seed that is correct for
+            // four bits. That is, denominator * inv ≡ 1 mod 2⁴.
+            uint256 inverse = (3 * denominator) ^ 2;
+
+            // Use the Newton-Raphson iteration to improve the precision. Thanks to Hensel's lifting lemma, this also
+            // works in modular arithmetic, doubling the correct bits in each step.
+            inverse *= 2 - denominator * inverse; // inverse mod 2⁸
+            inverse *= 2 - denominator * inverse; // inverse mod 2¹⁶
+            inverse *= 2 - denominator * inverse; // inverse mod 2³²
+            inverse *= 2 - denominator * inverse; // inverse mod 2⁶⁴
+            inverse *= 2 - denominator * inverse; // inverse mod 2¹²⁸
+            inverse *= 2 - denominator * inverse; // inverse mod 2²⁵⁶
+
+            // Because the division is now exact we can divide by multiplying with the modular inverse of denominator.
+            // This will give us the correct result modulo 2²⁵⁶. Since the preconditions guarantee that the outcome is
+            // less than 2²⁵⁶, this is the final result. We don't need to compute the high bits of the result and high
+            // is no longer required.
+            result = low * inverse;
+            return result;
+        }
+    }
+
+    // /**
+    //  * @dev Calculates x * y / denominator with full precision, following the selected rounding direction.
+    //  */
+    // function mulDiv(uint256 x, uint256 y, uint256 denominator, Rounding rounding) internal pure returns (uint256) {
+    //     return mulDiv(x, y, denominator) + toUint(unsignedRoundsUp(rounding) && mulmod(x, y, denominator) > 0);
+    // }
+
+    /**
+     * @dev Returns the absolute unsigned value of a signed value.
+     */
+    function abs(int256 n) internal pure returns (uint256) {
+        unchecked {
+            // Formula from the "Bit Twiddling Hacks" by Sean Eron Anderson.
+            // Since `n` is a signed integer, the generated bytecode will use the SAR opcode to perform the right shift,
+            // taking advantage of the most significant (or "sign" bit) in two's complement representation.
+            // This opcode adds new most significant bits set to the value of the previous most significant bit. As a result,
+            // the mask will either be `bytes32(0)` (if n is positive) or `~bytes32(0)` (if n is negative).
+            int256 mask = n >> 255;
+
+            // A `bytes32(0)` mask leaves the input unchanged, while a `~bytes32(0)` mask complements it.
+            return uint256((n + mask) ^ mask);
+        }
+    }
+
+    /**
+     * @dev Returns the multiplication of two unsigned integers, with a success flag (no overflow).
+     */
+    function tryMul(uint256 a, uint256 b) internal pure returns (bool success, uint256 result) {
+        unchecked {
+            uint256 c = a * b;
+             /// @solidity memory-safe-assembly
+            assembly {
+                // Only true when the multiplication doesn't overflow
+                // (c / a == b) || (a == 0)
+                success := or(eq(div(c, a), b), iszero(a))
+            }
+            // equivalent to: success ? c : 0
+            result = c * toUint(success);
+        }
+    }
+
+    /**
+     * @dev Returns the division of two unsigned integers, with a success flag (no division by zero).
+     */
+    function tryDiv(uint256 a, uint256 b) internal pure returns (bool success, uint256 result) {
+        unchecked {
+            success = b > 0;
+             /// @solidity memory-safe-assembly
+            assembly {
+                // The `DIV` opcode returns zero when the denominator is 0.
+                result := div(a, b)
+            }
+        }
+    }
+
+}

target_chains/ethereum/sdk/solidity/PythErrors.sol

@@ -49,4 +49,12 @@ library PythErrors {
     error InvalidTwapUpdateData();
     // The twap update data set is invalid.
     error InvalidTwapUpdateDataSet();
+    // The Input Price is negative.
+    error NegativeInputPrice();
+    // The Input Exponent is invalid.
+    error InvalidInputExpo();
+    // The target exponent is invalid.
+    error InvalidTargetExpo();
+    // The combined price is greater than int64.max.
+    error CombinedPriceOverflow();
 }