Merge pull request #29 from bdunahu/bdunahu

Small cleanups to up a lot of implementation details

6 files changed, 133 insertions, 160 deletions

diff --git a/inc/cache.h b/inc/cache.h
index 3b16ca1..ef9c9e4 100644
--- a/inc/cache.h
+++ b/inc/cache.h
@@ -42,6 +42,27 @@ class Cache : public Storage
 
   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.
diff --git a/inc/dram.h b/inc/dram.h
index c7f927a..e6db633 100644
--- a/inc/dram.h
+++ b/inc/dram.h
@@ -32,22 +32,25 @@ class Dram : public Storage
 
   private:
 	/**
-	 * Helper for `write` a word
+	 * 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
 	 */
-	void do_write(signed int, int);
-	/**
-	 * Helper for writing a line.
-	 */
-	void
-	do_write_line(std::array<signed int, LINE_SIZE> data_line, int address);
-	/**
-	 * Helper for `read` a line
-	 */
-	void do_read(std::array<signed int, LINE_SIZE> &data_line, int address);
+	Response process(
+		Accessor accessor,
+		int address,
+		std::function<void(int line, int word)> request_handler);
 	/**
-	 * Helper for reading a word.
+	 * Returns OK if `accessor` is allowed to complete its request this cycle.
+	 * Handles wait times, side door, 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.
 	 */
-	void do_read_word(signed int &data, int address);
+	Response is_access_cleared(Accessor accessor);
 };
 
 std::ostream &operator<<(std::ostream &os, const Dram &d);
diff --git a/inc/utils.h b/inc/utils.h
index aa8831b..df8d374 100644
--- a/inc/utils.h
+++ b/inc/utils.h
@@ -20,6 +20,20 @@ void get_bit_fields(int address, int *tag, int *index, int *offset);
  */
 const std::string string_format(const char *const zcFormat, ...);
 
+/**
+ * Given `address`, returns an address that is within the current memory size
+ * using a clean wrap.
+ * @param an address
+ * @return an address guaranteed to be within range.
+ */
 int wrap_address(int address);
 
+/**
+ * Given `address`, returns the line and word it is in.
+ * @param an address
+ * @param the line (row) `address` is in
+ * @param the word (column) `address` corresponds to
+ */
+void get_memory_index(int address, int &line, int &word);
+
 #endif /* UTILS_H_INCLUDED */
diff --git a/src/storage/cache.cc b/src/storage/cache.cc
index f15c919..8acdf08 100644
--- a/src/storage/cache.cc
+++ b/src/storage/cache.cc
@@ -27,51 +27,20 @@ Cache::~Cache()
 
 Response Cache::write_word(Accessor accessor, signed int data, int address)
 {
-	Response 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) {
-			int tag, index, offset;
-			get_bit_fields(address, &tag, &index, &offset);
-			this->data->at(index).at(offset) = data;
-			this->meta[index].at(1) = 1;
-			r = OK;
-		}
-	}
-
-	return r;
+	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)
 {
-	Response 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) {
-			int tag, index, offset;
-			get_bit_fields(address, &tag, &index, &offset);
-			this->data->at(index) = data_line;
-			this->meta[index].at(1) = 1;
-			r = OK;
-		}
-	}
-
-	return r;
+	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
@@ -80,26 +49,38 @@ Response Cache::read_line(
 	int address,
 	std::array<signed int, LINE_SIZE> &data_line)
 {
-	Response r = WAIT;
-	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) {
-			int tag, index, offset;
-			get_bit_fields(address, &tag, &index, &offset);
-			data_line = this->data->at(index);
-			r = OK;
-		}
+	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_bit_fields(address, &tag, &index, &offset);
+		request_handler(index, offset);
 	}
 	return r;
 }
 
-Response Cache::read_word(Accessor accessor, int address, signed int &data)
+Response Cache::is_access_cleared(Accessor accessor, int address)
 {
-	Response r = WAIT;
+	Response r;
+	r = WAIT;
+	/* Do this first--then process the first cycle immediately. */
 	if (this->requester == IDLE)
 		this->requester = accessor;
 	if (this->requester == accessor) {
@@ -107,9 +88,6 @@ Response Cache::read_word(Accessor accessor, int address, signed int &data)
 		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;
 		}
 	}
diff --git a/src/storage/dram.cc b/src/storage/dram.cc
index 20db47e..2c24b4b 100644
--- a/src/storage/dram.cc
+++ b/src/storage/dram.cc
@@ -21,118 +21,69 @@ Dram::Dram(int delay)
 
 Dram::~Dram() { delete this->data; }
 
-void Dram::do_write(signed int data, int address)
+Response Dram::write_line(
+	Accessor accessor, std::array<signed int, LINE_SIZE> data_line, int address)
 {
-	address = wrap_address(address);
-	int line = address / LINE_SIZE;
-	int word = address % LINE_SIZE;
-
-	this->data->at(line).at(word) = data;
+	return process(accessor, address, [&](int line, int word) {
+		(void)word;
+		this->data->at(line) = data_line;
+	});
 }
 
-void Dram::do_write_line(
-	std::array<signed int, LINE_SIZE> data_line, int address)
+Response Dram::write_word(Accessor accessor, signed int data, int address)
 {
-	address = wrap_address(address);
-	int line = address / LINE_SIZE;
-	this->data->at(line) = data_line;
+	return process(accessor, address, [&](int line, int word) {
+		this->data->at(line).at(word) = data;
+	});
 }
 
-void Dram::do_read(std::array<signed int, LINE_SIZE> &data_line, int address)
+// TODO requires testing
+Response Dram::read_line(
+	Accessor accessor,
+	int address,
+	std::array<signed int, LINE_SIZE> &data_line)
 {
-	address = wrap_address(address);
-	int line = address / LINE_SIZE;
-	data_line = this->data->at(line);
+	return process(accessor, address, [&](int line, int word) {
+		(void)word;
+		data_line = this->data->at(line);
+	});
 }
 
-void Dram::do_read_word(signed int &data, int address)
+Response Dram::read_word(Accessor accessor, int address, signed int &data)
 {
-	address = wrap_address(address);
-	int line = address / LINE_SIZE;
-	int word = address % LINE_SIZE;
-	data = this->data->at(line).at(word);
+	return process(accessor, address, [&](int line, int word) {
+		data = this->data->at(line).at(word);
+	});
 }
 
-Response Dram::write_line(
-	Accessor accessor, std::array<signed int, LINE_SIZE> data_line, int address)
+Response Dram::process(
+	Accessor accessor,
+	int address,
+	std::function<void(int line, int word)> request_handler)
 {
-	Response r = WAIT;
-
-	if (accessor == SIDE) {
-		this->do_write_line(data_line, address);
-		r = OK;
-	} else {
-		/* Do this first--then process the first cycle immediately. */
-		if (this->requester == IDLE)
-			this->requester = accessor;
-
-		if (this->requester == accessor) {
-			if (this->wait_time == 0) {
-				this->do_write_line(data_line, address);
-				r = OK;
-			}
-		}
+	Response r = this->is_access_cleared(accessor);
+	if (r == OK) {
+		int line, word;
+		get_memory_index(address, line, word);
+		request_handler(line, word);
 	}
 	return r;
 }
 
-Response Dram::write_word(Accessor accessor, signed int data, int address)
+Response Dram::is_access_cleared(Accessor accessor)
 {
-	Response r = WAIT;
-
-	if (accessor == SIDE) {
-		this->do_write(data, address);
+	Response r;
+	r = WAIT;
+	/* Do this first--then process the first cycle immediately. */
+	if (accessor == SIDE)
 		r = OK;
-	} else {
-		/* Do this first--then process the first cycle immediately. */
+	else {
 		if (this->requester == IDLE)
 			this->requester = accessor;
-
-		if (this->requester == accessor) {
-			if (this->wait_time == 0) {
-				this->do_write(data, address);
+		if (this->requester == accessor)
+			if (this->wait_time == 0)
 				r = OK;
-			}
-		}
 	}
-
-	return r;
-}
-
-Response Dram::read_line(
-	Accessor accessor,
-	int address,
-	std::array<signed int, LINE_SIZE> &data_line)
-{
-	Response r = WAIT;
-
-	if (this->requester == IDLE)
-		this->requester = accessor;
-
-	if (this->requester == accessor) {
-		if (this->wait_time == 0) {
-			this->do_read(data_line, address);
-			r = OK;
-		}
-	}
-
-	return r;
-}
-
-Response Dram::read_word(Accessor accessor, int address, signed int &data)
-{
-	Response r = WAIT;
-
-	if (this->requester == IDLE)
-		this->requester = accessor;
-
-	if (this->requester == accessor) {
-		if (this->wait_time == 0) {
-			this->do_read_word(data, address);
-			r = OK;
-		}
-	}
-
 	return r;
 }
 
diff --git a/src/utils/utils.cc b/src/utils/utils.cc
index ebbc1e9..3a11c2c 100644
--- a/src/utils/utils.cc
+++ b/src/utils/utils.cc
@@ -34,3 +34,9 @@ int wrap_address(int address) {
 	}
 	return address % MEM_WORDS;
 }
+
+void get_memory_index(int address, int &line, int &word)
+{
+	line = wrap_address(address) / LINE_SIZE;
+	word = address % LINE_SIZE;
+}