GCD in solidity

gcd.sol

function gcd(uint256 x, uint256 y) internal pure returns(uint256 z){
        assembly{
            for {} 1 {} {
                if eq(y,0) {
                    z := x
                    break
                }
                let temp := mod(x,y)
                x := y
                y := temp
            }
        }
    }