Method for controling cache system comprising direct-mapped cache and fully-associative buffer

A method for controlling a cache system constructed with a direct-mapped cache configured with a small block size and a fully associative spatial buffer configured with a large block size, consisting of a plurality of small blocks, the method comprising the steps of:

• (a) checking whether an empty large block exists in the fully associative buffer if accesses to the direct-mapped cache and the fully associative buffer are a miss;
• (b) if the empty large block exists in the step (a), performing step (c5)
• (c) if no empty block exists in the step (a), performing steps (c1)-(c5);
• (c1) checking a small block of data that has been accessed among the large block of data to be expelled from the fully associative buffer according to a first-in-first-out (FIFO) algorithm;
• (c2) checking whether the small block of data to be expelled from the direct-mapped cache has been in a written state;
• (c3) if the small block of data to be expelled has been in a written state, moving the small block of data to be expelled into a main memory;
• (c4) copying the small block of data confirmed to have been accessed in the step (c1) to the direct-mapped cache;
• and
• (c5) copying data of an address accessed in the step (a) and data of adjacent addresses in the large block to the fully associative buffer according to a FIFO algorithm.