Write line, dirty cache eviction, cache load word/line (for future multilevel cache implementation)

1 files changed, 42 insertions, 7 deletions

diff --git a/src/storage/cache.cc b/src/storage/cache.cc
index 1a8a10b..66603e2 100644
--- a/src/storage/cache.cc
+++ b/src/storage/cache.cc
@@ -49,10 +49,43 @@ 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)
+// TODO: tests for multi level cache
+Response Cache::read(Accessor accessor, int address, std::array<signed int, LINE_SIZE> &data)
 {
-	return WAIT;
+	Response r = WAIT;
+	if (this->requester == IDLE)
+		this->requester = accessor;
+	if (this->requester == accessor) {
+		fetch_resource(address);
+		if (this->is_waiting)
+			r = BLOCKED;
+		else if (this->wait_time == 0) {
+			int tag, index, offset;
+			get_bit_fields(address, &tag, &index, &offset);
+			data = this->data->at(index);
+			r = OK;
+		}
+	}
+	return r;
+}
+
+Response Cache::read_word(Accessor accessor, int address, signed int &data)
+{
+	Response r = WAIT;
+	if (this->requester == IDLE)
+		this->requester = accessor;
+	if (this->requester == accessor) {
+		fetch_resource(address);
+		if (this->is_waiting)
+			r = BLOCKED;
+		else if (this->wait_time == 0) {
+			int tag, index, offset;
+			get_bit_fields(address, &tag, &index, &offset);
+			data = this->data->at(index)->at(offset);
+			r = OK;
+		}
+	}
+	return r;
 }
 
 void Cache::fetch_resource(int expected)
@@ -64,19 +97,21 @@ void Cache::fetch_resource(int expected)
 
 	get_bit_fields(expected, &tag, &index, &offset);
 	meta = &this->meta.at(index);
+	actual = this->data->at(index);
 
 	if (meta->at(0) != tag) {
 		// address not in cache
 		if (meta->at(1) >= 0) {
 			// occupant is dirty
-			// TODO
-			r = WAIT;
+			// writing line to DRam in case of dirty cache eviction
+			r = this->lower->write_line(L1CACHE, actual, ((index << LINE_SPEC) + (meta->at(0) << (L1_CACHE_SPEC + LINE_SPEC))));
+			if (r == OK) {
+				meta->at(1) = -1;
+			}
 		} else {
-			actual = this->data->at(index);
 			r = this->lower->read(L1CACHE, expected, actual);
 			if (r == OK) {
 				meta->at(0) = tag;
-				meta->at(1) = -1;
 			}
 		}
 	}