Assembly shift storage

Smart Contracts
1

I intend to modify the data in slot 0 using assembly, but the output is not as anticipated. Could someone help me identify where the mistakes are, please?

function changeSlot0()public returns(bytes32) onlyOwner{
        bytes32 re;
        assembly{
            let slot0 := sload(0)
            let ans := shl(slot0,16)
            sstore(0,ans)
            re := sload(0)
        }
        return re;
    }
3

The parameters for the left shift method are reversed. shl(x, y) represents a logical shift left of y by x bits. So you should swap slot0 and 16.

4

Thank you, I think it's very basic... anyway, I got it.