Add implementation functions for checking out a register.

3 files changed, 53 insertions, 9 deletions

diff --git a/inc/instrDTO.h b/inc/instrDTO.h
index 2a6ab1f..77a223e 100644
--- a/inc/instrDTO.h
+++ b/inc/instrDTO.h
@@ -1,9 +1,10 @@
 #ifndef INSTRDTO_H
 #define INSTRDTO_H
-#include <string>
+#include "accessor.h"
+#include "instr.h"
 #include <functional>
+#include <string>
 #include <unordered_map>
-#include "accessor.h"
 
 class InstrDTO
 {
@@ -39,9 +40,9 @@ class InstrDTO
 	 */
 	signed int get_s3();
 	/**
-	 * @return the string representation of oper.
+	 * @return the mnemonic of the instruction
 	 */
-	std::string get_oper_name();
+	Mnemonic get_mnemonic();
 
 	/**
 	 * @param set hist key
@@ -63,6 +64,10 @@ class InstrDTO
 	 * @param s3
 	 */
 	void set_s3(signed int);
+	/**
+	 * @param the mnemonic of the instruction
+	 */
+	void set_mnemonic(Mnemonic);
 
   private:
 	/**
@@ -82,10 +87,10 @@ class InstrDTO
 	signed int s1;
 	signed int s2;
 	signed int s3;
-  /**
-   * The operation to be conducted during the execute phase.
-   */
-	std::function<void()> instr;
+	/**
+	 * The mnemonic of the operation.
+	 */
+	Mnemonic mnemonic;
 };
 
 #endif /* INSTRDTO_H_INCLUDED */
diff --git a/inc/response.h b/inc/response.h
index 6cd6678..05e9352 100644
--- a/inc/response.h
+++ b/inc/response.h
@@ -6,6 +6,7 @@ enum Response {
 	OK,
 	WAIT,
 	BLOCKED,
+	STALLED,
 };
 
 std::ostream &operator<<(std::ostream &os, Response r);
diff --git a/inc/stage.h b/inc/stage.h
index f6bad41..0348263 100644
--- a/inc/stage.h
+++ b/inc/stage.h
@@ -1,11 +1,12 @@
 #ifndef STAGE_H
 #define STAGE_H
+#include "accessor.h"
 #include "definitions.h"
 #include "instrDTO.h"
 #include "response.h"
 #include "storage.h"
-#include "accessor.h"
 #include <array>
+#include <set>
 
 class Stage
 {
@@ -28,6 +29,16 @@ class Stage
 
   protected:
 	/**
+	 * Facilitates register checkout.
+	 * It does this by checking that the register passed in is not currently
+	 * checked out. If true, then replaces r with the value of the register and
+	 * returns OK. If false, returns STALLED.
+	 *
+	 * @param the registers number, to be dereferenced.
+	 * @return OK if `r` is not checked out, STALLED otherwise.
+	 */
+	Response check_out(unsigned int &r);
+	/**
 	 * The name of the pipeline stage.
 	 */
 	Accessor id;
@@ -59,6 +70,33 @@ class Stage
 	 * The current clock cycle.
 	 */
 	static int clock_cycle;
+
+  private:
+	/**
+	 * Helper for `check_out`.
+	 * Returns true if r are not checked out, false otherwise.
+	 * @param a list of register numbers.
+	 * @return true if registers are not in checked_out, false otherwise.
+	 */
+	bool is_checked_out(unsigned int r);
+	/**
+	 * Helper for `check_out`.
+	 * Checks out a single register, and places it in checked_out.
+	 * @param a register number.
+	 * @return the value in the register.
+	 */
+	signed int check_out_register(unsigned int r);
+	// TODO fix this comment after writeback stage
+	/**
+	 * Helper for `check_out_register`
+	 * @param the register number.
+	 * @return the value in the associated register.
+	 */
+	signed int dereference_register(unsigned int r);
+	/**
+	 * The set of registers currently checked out.
+	 */
+	static std::set<unsigned int> checked_out;
 };
 
 #endif /* STAGE_H_INCLUDED */