From 9bd18b0499d5096bc91b09a2d26e700ca1560de4 Mon Sep 17 00:00:00 2001
From: bd <bdunahu@operationnull.com>
Date: Sun, 9 Mar 2025 20:15:45 -0400
Subject: Untested implementation for loading absent data into cache

---
 src/storage/cache.cc   | 38 ++++++++++++++++++++++++++++++++------
 src/storage/dram.cc    | 11 +++++++----
 src/storage/storage.cc |  2 +-
 3 files changed, 40 insertions(+), 11 deletions(-)

(limited to 'src/storage')

diff --git a/src/storage/cache.cc b/src/storage/cache.cc
index e0eaf58..ec14ce6 100644
--- a/src/storage/cache.cc
+++ b/src/storage/cache.cc
@@ -1,6 +1,7 @@
 #include "cache.h"
 #include "definitions.h"
 #include "response.h"
+#include "utils.h"
 #include <bits/stdc++.h>
 
 Cache::Cache(int lines, Storage *lower, int delay)
@@ -9,8 +10,7 @@ Cache::Cache(int lines, Storage *lower, int delay)
 	this->data->resize(L1_CACHE_SIZE);
 	this->lower = lower;
 	this->delay = delay;
-	for (int i = 0; i < L1_CACHE_SIZE; ++i)
-		this->stat[i] = 0b01;
+	this->meta.fill({-1});
 }
 
 Cache::~Cache() { delete this->data; }
@@ -25,8 +25,9 @@ Response Cache::write(Accessor accessor, signed int data, int address)
 
 	if (this->requester == accessor) {
 		fetch_resource(address);
-		if (this->wait_time == 0) {
-			// this->do_write(data, address);
+		if (this->is_waiting == true)
+			r = BLOCKED;
+		else if (this->wait_time == 0) {
 			r = OK;
 		}
 	}
@@ -34,8 +35,33 @@ Response Cache::write(Accessor accessor, signed int data, int address)
 	return r;
 }
 
-Response Cache::read(Accessor accessor, int address, std::array<signed int, LINE_SIZE>& data) { return WAIT; }
+Response Cache::read(
+	Accessor accessor, int address, std::array<signed int, LINE_SIZE> &data)
+{
+	return WAIT;
+}
+
+void Cache::fetch_resource(int expected)
+{
+	Response r = OK;
+	int etag, index, atag;
+	std::array<signed int, LINE_SIZE> actual;
+	std::array<int, 2> meta;
 
-void Cache::fetch_resource(int address) {
+	get_bit_fields(expected, &etag, &index, nullptr);
+	meta = this->meta.at(index);
+
+	if (atag != etag) {
+		// address not in cache
+		if (this->meta[index][0]) {
+			// occupant is dirty
+			// TODO
+			r = WAIT;
+		} else {
+			actual = this->data->at(index);
+			r = this->lower->read(L1CACHE, expected, actual);
+		}
+	}
 
+	this->is_waiting = (r == OK) ? false : true;
 }
diff --git a/src/storage/dram.cc b/src/storage/dram.cc
index e3f3c9a..23dedc0 100644
--- a/src/storage/dram.cc
+++ b/src/storage/dram.cc
@@ -46,12 +46,15 @@ Response Dram::write(Accessor accessor, signed int data, int address)
 	return r;
 }
 
-void Dram::do_read(std::array<signed int, LINE_SIZE>& data_line, int address){
+void Dram::do_read(std::array<signed int, LINE_SIZE> &data_line, int address)
+{
 	int line = address / LINE_SIZE;
 	data_line = this->data->at(line);
 }
 
-Response Dram::read(Accessor accessor, int address, std::array<signed int, LINE_SIZE>& data) { 
+Response Dram::read(
+	Accessor accessor, int address, std::array<signed int, LINE_SIZE> &data)
+{
 	Response r = WAIT;
 	if (this->requester == IDLE)
 		this->requester = accessor;
@@ -61,5 +64,5 @@ Response Dram::read(Accessor accessor, int address, std::array<signed int, LINE_
 			r = OK;
 		}
 	}
-	return r; 
- }
+	return r;
+}
diff --git a/src/storage/storage.cc b/src/storage/storage.cc
index f382b3e..61531d1 100644
--- a/src/storage/storage.cc
+++ b/src/storage/storage.cc
@@ -18,7 +18,7 @@ void Storage::resolve()
 	if (this->wait_time == 0) {
 		this->requester = IDLE;
 		this->wait_time = delay;
-	} else if (this->requester != IDLE && !this->is_blocked) {
+	} else if (this->requester != IDLE && !this->is_waiting) {
 		--this->wait_time;
 	}
 }
-- 
cgit v1.2.3