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#include "cache.h"
#include "definitions.h"
#include "response.h"
#include "utils.h"
#include <bits/stdc++.h>
#include <iostream>
#include <iterator>
Cache::Cache(Storage *lower, int delay)
{
this->data = new std::vector<std::array<signed int, LINE_SIZE>>;
this->data->resize(L1_CACHE_LINES);
this->delay = delay;
this->is_waiting = false;
this->lower = lower;
this->meta.fill({-1, -1});
this->requester = IDLE;
this->wait_time = this->delay;
}
Cache::~Cache()
{
delete this->lower;
delete this->data;
}
Response Cache::write_word(Accessor accessor, signed int data, int address)
{
return process(accessor, address, [&](int index, int offset) {
this->data->at(index).at(offset) = data;
this->meta[index].at(1) = 1;
});
}
Response Cache::write_line(
Accessor accessor, std::array<signed int, LINE_SIZE> data_line, int address)
{
return process(accessor, address, [&](int index, int offset) {
(void)offset;
this->data->at(index) = data_line;
this->meta[index].at(1) = 1;
});
}
// TODO: tests for multi level cache
Response Cache::read_line(
Accessor accessor,
int address,
std::array<signed int, LINE_SIZE> &data_line)
{
return process(accessor, address, [&](int index, int offset) {
(void)offset;
data_line = this->data->at(index);
});
}
Response Cache::read_word(Accessor accessor, int address, signed int &data)
{
return process(accessor, address, [&](int index, int offset) {
data = this->data->at(index).at(offset);
});
}
Response Cache::process(
Accessor accessor,
int address,
std::function<void(int index, int offset)> request_handler)
{
Response r = this->is_access_cleared(accessor, address);
if (r == OK) {
int tag, index, offset;
get_cache_fields(address, &tag, &index, &offset);
request_handler(index, offset);
}
return r;
}
Response Cache::is_access_cleared(Accessor accessor, int address)
{
Response r;
r = WAIT;
/* Do this first--then process the first cycle immediately. */
if (this->requester == IDLE)
this->requester = accessor;
if (this->requester == accessor) {
handle_miss(address);
if (this->is_waiting)
r = BLOCKED;
else if (this->wait_time == 0) {
this->requester = IDLE;
this->wait_time = delay;
r = OK;
} else {
--this->wait_time;
}
}
return r;
}
void Cache::handle_miss(int expected)
{
Response r, q;
int tag, index, offset;
std::array<signed int, LINE_SIZE> *actual;
std::array<int, 2> *meta;
get_cache_fields(expected, &tag, &index, &offset);
r = OK;
meta = &this->meta.at(index);
actual = &this->data->at(index);
if (meta->at(0) != tag) {
r = WAIT;
// address not in cache
if (meta->at(1) >= 0) {
// occupant is dirty
// writing line to DRam in case of dirty cache eviction
q = this->lower->write_line(
L1CACHE, *actual,
((index << LINE_SPEC) +
(meta->at(0) << (L1_CACHE_LINE_SPEC + LINE_SPEC))));
if (q == OK) {
meta->at(1) = -1;
}
} else {
q = this->lower->read_line(L1CACHE, expected, *actual);
if (q == OK) {
meta->at(0) = tag;
}
}
}
this->is_waiting = (r == OK) ? false : true;
}
std::array<std::array<int, 2>, L1_CACHE_LINES> Cache::get_meta() const
{
std::array<std::array<int, 2>, L1_CACHE_LINES> ret;
std::copy(std::begin(this->meta), std::end(this->meta), std::begin(ret));
return ret;
}
std::ostream &operator<<(std::ostream &os, const Cache &c)
{
const auto default_flags = std::cout.flags();
const auto default_fill = std::cout.fill();
std::vector<std::array<signed int, LINE_SIZE>> data =
c.view(0, L1_CACHE_LINES);
std::array<std::array<int, 2>, L1_CACHE_LINES> meta = c.get_meta();
os << " " << std::setfill(' ') << std::setw(L1_CACHE_LINE_SPEC + 2)
<< "INDEX"
<< " | " << std::setfill(' ') << std::setw((8 + 3) * 4 - 1) << "DATA"
<< " | " << std::setfill(' ')
<< std::setw(MEM_LINE_SPEC - L1_CACHE_LINE_SPEC + 2) << "TAG"
<< " | D" << std::endl;
for (int i = 0; i < L1_CACHE_LINES; ++i) {
os << " 0b" << std::setw(L1_CACHE_LINE_SPEC)
<< std::bitset<L1_CACHE_LINE_SPEC>(i) << " | ";
for (int j = 0; j < LINE_SIZE; ++j) {
os << "0x" << std::setfill('0') << std::setw(8) << std::hex
<< data.at(i).at(j) << " ";
}
os << "| 0b" << std::setfill(' ');
if (meta.at(i)[0] < 0)
os << std::setfill('?')
<< std::setw(MEM_LINE_SPEC - L1_CACHE_LINE_SPEC) << "";
else
os << std::bitset<MEM_LINE_SPEC - L1_CACHE_LINE_SPEC>(
meta.at(i)[0]);
os << " | " << (int)(meta.at(i)[0] >= 0) << std::endl;
}
std::cout.flags(default_flags);
std::cout.fill(default_fill);
return os;
}
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