Controller and control method

A controller for controlling a computing storage device that is connectable to a host and includes a storage, the controller comprising:

• a first interface configured to receive an I/O command from the host, the I/O command being designating first host data;
• a second interface configured to transmit and receive the first host data to and from the storage;
• a memory for storing a copy of the first host data designated in the I/O command;
• a virtual register table having a virtual address specified by a page number assigned to a page in which data to be used to process a calculation instruction in accordance with a calculation option accompanying the first host data is stored and a page offset, and a data size of the data, the virtual address and the data size being associated with each virtual register number identified based on the calculation option;
• a memory management unit configured to store, into the memory, the copy of the first host data designated in the I/O command, and update the virtual register table;
• and
• a calculation processing unit configured to process the calculation instruction using the first host data designated in the I/O command, by referring to the virtual register table.