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#ifndef CACHE_H
#define CACHE_H
#include "definitions.h"
#include "storage.h"
#include <array>
#include <ostream>
class Cache : public Storage
{
public:
/**
* Constructor.
* @param The number of `lines` contained in memory. The total number of
* words is this number multiplied by LINE_SIZE.
* @param The next lowest level in storage. Methods from this object are
* called in case of a cache miss.
* @param The number of clock cycles each access takes.
* @return A new cache object.
*/
Cache(Storage *lower, int delay);
~Cache();
Response
write_word(Accessor accessor, signed int data, int address) override;
Response write_line(
Accessor accessor,
std::array<signed int, LINE_SIZE> data_line,
int address) override;
Response read_line(
Accessor accessor,
int address,
std::array<signed int, LINE_SIZE> &data_line) override;
Response
read_word(Accessor accessor, int address, signed int &data) override;
/**
* Getter for the meta attribute.
* TODO this doesn't seem like good object-oriented practice.
* @return this->meta
*/
std::array<std::array<int, 2>, L1_CACHE_LINES> get_meta() const;
private:
/**
* Helper for all access methods.
* Calls `request_handler` when `accessor` is allowed to complete its
* request cycle.
* @param the source making the request
* @param the address to write to
* @param the function to call when an access should be completed
*/
Response process(
Accessor accessor,
int address,
std::function<void(int index, int offset)> request_handler);
/**
* Returns OK if `accessor` is allowed to complete its request this cycle.
* Handles cache misses, wait times, and setting the current accessor this
* storage is serving.
* @param the accessor asking for a resource
* @return whether or not the access can be carried out this function call.
*/
Response is_access_cleared(Accessor accessor, int address);
/**
* Helper for access_cleared.
* Fetches `address` from a lower level of storage if it is not already
* present. If it is not, temporarily sets the is_blocked attribute of this
* cache level to true, and the victim line is chosen/written back.
* @param the address that must be present in cache.
*/
void handle_miss(int address);
/**
* An array of metadata about elements in `data`.
* If the first value of an element is negative, the corresponding
* element in `data` is invalid. If the most second value of an element
* is nonzero, the corresponding element in `data` is dirty.
*/
std::array<std::array<int, 2>, L1_CACHE_LINES> meta;
};
std::ostream &operator<<(std::ostream &os, const Cache &c);
#endif /* CACHE_H_INCLUDED */
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