Read Precompiles

Custom precompiles at addresses 0x0800--0x0807 provide lock-free reads of aggregate market data from the core engine's EngineSnapshot.

Address Map

Gas Costs

All precompiles cost 1 gas (nominal). The chain runs single-validator with no gas market -- gas exists only to satisfy EVM mechanical requirements.

OlympusReader Contract

The OlympusReader contract is deployed at genesis at address 0x0C00. It provides typed Solidity wrappers around all 8 read precompiles, giving you autocomplete, compile-time types, and direct calls without library linking.

Solidity Usage

Import the OlympusReader interface and call it at 0x0C00:

import {OlympusReader} from "./IOlympusReader.sol";

contract MyStrategy {
    OlympusReader constant reader = OlympusReader(address(0x0C00));

    function checkSpread(string calldata instrumentId) external view returns (uint256) {
        OlympusReader.BBO memory bbo = reader.getBBO(instrumentId);
        return bbo.askPrice - bbo.bidPrice;
    }

    function getMid(string calldata instrumentId) external view returns (uint256) {
        return reader.getMidPrice(instrumentId);
    }

    function lastTradePrice(string calldata instrumentId) external view returns (uint256) {
        (uint256 price,,) = reader.getLastTrade(instrumentId);
        return price;
    }
}

Or call precompiles directly via staticcall:

(bool success, bytes memory data) = address(0x0800).staticcall(
    abi.encode("AAPL-USD")
);
require(success);
(uint256 bidPrice, uint256 bidSize, uint256 askPrice, uint256 askSize) =
    abi.decode(data, (uint256, uint256, uint256, uint256));

Data Encoding

All prices and quantities are encoded as uint256 with 18 decimal places (like wei). For example:

• Price 150.50 at price_scale=2 (raw 15050) becomes 150500000000000000000
• Quantity 100 shares at qty_scale=0 (raw 100) becomes 100000000000000000000

The GetOHLCV precompile currently returns zeros -- kline snapshot integration is pending.