invalid_b
invalid_e = invalid_b - 1
int xb1 = invalid_b;
int xb2 = invalid_b;
xb1 = invalid_b;
xb2 = invalid_b;
xb1 = invalid_b; // Invalidate both
xb2 = invalid_b;
xb1 = invalid_b; // Invalidate
xb2 = invalid_b; // Invalidate