Half Adder的算法-SIGTSTP-运行时错误

Question

#Addition
def add(x,y):
    while(y>0):
        u = x^y
        v = x and y
        x = u
        y = v<<1
    return (x)

for _ in range(int(input())):
    a = input()
    b = input()
    x = int(a,2)
    y = int(b,2)
    ans = add(x,y)
    print(ans)

为什么我会收到此错误，而且我也不明白为什么我的循环没有停止