The A/S is the authorized shares, which is the total number of common shares that the company is authorized to issue. It does NOT mean that the company has to issue ALL of these shares.
The O/S is the total number of shares that the company HAS ALREADY issued. This includes restricted shares and unrestricted shares and refers to COMMON STOCK, not preferred stock.
The float is the total number of unrestricted common shares that are issued and outstanding (tradable).