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// Memory subsystem for the RISC-V[ECTOR] mini-ISA
// Copyright (C) 2025 Siddarth Suresh
// Copyright (C) 2025 bdunahu
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
// You should have received a copy of the GNU General Public License
// along with this program. If not, see <https://www.gnu.org/licenses/>.
#ifndef STORAGE_H
#define STORAGE_H
#include "definitions.h"
#include <algorithm>
#include <array>
#include <functional>
#include <map>
#include <vector>
// clang-format off
/**
* Ensures address is within the current memory size using a clean wrap.
* @param an address
*/
#define WRAP_ADDRESS(a) \
((a < 0) ? ((a % MEM_WORDS) + MEM_WORDS) % MEM_WORDS : a % MEM_WORDS)
// clang-format on
class Storage
{
public:
/**
* Constructor.
* @param The time an access to this storage device takes.
* @return A newly allocated storage object.
*/
Storage(int delay);
virtual ~Storage() = default;
/**
* Write `data` word into `address`.
* @param the source making the request.
* @param the data (hexadecimal) to write.
* @param the address to write to.
* @return 1 if the request was completed, 0 otherwise.
*/
virtual int write_word(void *id, signed int data, int address) = 0;
virtual int write_line(void *id, std::array<signed int, LINE_SIZE> data_line, int address) = 0;
/**
* Get the data line at `address`.
* @param the source making the request.
* @param the address being accessed.
* @param the data being returned
* @return 1 if the request was completed, 0 otherwise
*/
virtual int read_line(void *id, int address, std::array<signed int, LINE_SIZE> &data) = 0;
virtual int read_word(void *id, int address, signed int &data) = 0;
/**
* @return a copy of `this->data'
*/
std::vector<std::array<signed int, LINE_SIZE>> get_data() const;
protected:
/**
* Helper for all access methods.
* Calls `request_handler` when `id` is allowed to complete its
* request cycle.
* May include extra checks depending on storage device.
* @param the source making the request
* @param the address to write to
* @param the function to call when an access should be completed
*/
virtual int
process(void *id, int address, std::function<void(int index, int offset)> request_handler) = 0;
/**
* Helper for process. Given `id`, returns 0 if the request should trivially be ignored.
* @param the source making the request
* @return 0 if the request should not be completed, 1 if it should be evaluated further.
*/
int preprocess(void *id);
/**
* Returns OK if `id` should complete its request this cycle. In the case it can, automatically
* clears the current requester.
* @param the id asking for a resource
* @return 1 if the access can be carried out this function call, 0 otherwise.
*/
int is_data_ready();
/**
* The data currently stored in this level of storage.
*/
std::vector<std::array<signed int, LINE_SIZE>> *data;
/**
* A pointer to the next lowest level of storage.
* Used in case of cache misses.
*/
Storage *lower;
/**
* The id currently being serviced.
*/
void *current_request;
/**
* The number of clock cycles this level of storage takes to complete
* requests.
*/
int delay;
/**
* The number of cycles until the current request is completed.
*/
int wait_time;
};
#endif /* STORAGE_H_INCLUDED */
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