Storage basics

storage-basics.sol

//SPDX-License-Identifier: MIT
pragma solidity 0.8.19;

contract StorageBasics {
    uint256 x = 1;
    uint256 y = 23;
    uint256 z = 48;

    uint128 a = 1;
    uint128 b = 2;

    function getXYul() external view returns (bytes32 ret) {
        assembly {
            ret := sload(x.slot)
        }
    }

    function getSlot(uint256 slot) external view returns (bytes32 ret) {
        assembly {
            ret := sload(slot)
        }
    }
    // dangerous operation, never allow external actors to set arbitrary slot values
    function setSlot(uint256 slot, uint256 value) external {
        assembly {
            sstore(slot, value)
        }
    }
}