Merge pull request #46 from bdunahu/bdunahu

 Ensure all stages only do work if they are not 'OK' 

6 files changed, 55 insertions, 29 deletions

diff --git a/inc/ex.h b/inc/ex.h
index 6d4254e..e4c9d2b 100644
--- a/inc/ex.h
+++ b/inc/ex.h
@@ -25,7 +25,7 @@ class EX : public Stage
 	 */
 	std::unordered_map<
 		Mnemonic,
-		std::function<void(signed int &s1, signed int s2, signed int s3)>>
+		std::function<void(signed int &s1, signed int s2, signed int s3, unsigned int pc)>>
 		instr_map;
 };
 
diff --git a/inc/id.h b/inc/id.h
index ebbe290..fd8c874 100644
--- a/inc/id.h
+++ b/inc/id.h
@@ -66,8 +66,8 @@ class ID : public Stage
 	 */
 	void get_instr_fields(signed int &s1, signed int &s2, signed int &s3, Mnemonic &m, Type &t);
 	void decode_R_type(signed int &s1, signed int &s2, signed int &s3);
-	void decode_I_type(signed int &s1, signed int &s2, signed int &s3);
-	void decode_J_type(signed int &s1, signed int &s2);
+	void decode_I_type(signed int &s1, signed int &s2, signed int &s3, Mnemonic &m);
+	void decode_J_type(signed int &s1, signed int &s2, signed int &s3);
 	/**
 	 * Helper for `get_instr_fields`.
 	 * Given a raw instruction, returns the mnemonic and type.
diff --git a/inc/instr.h b/inc/instr.h
index d17613d..2b1807a 100644
--- a/inc/instr.h
+++ b/inc/instr.h
@@ -1,7 +1,6 @@
 #ifndef INSTR_H
 #define INSTR_H
 #include <functional>
-#include <iostream>
 #include <unordered_map>
 
 enum Mnemonic {
@@ -45,12 +44,7 @@ enum Mnemonic {
 	NOP,
 };
 
-enum Type {
-	R,
-	I,
-	J,
-	INV
-};
+enum Type { R, I, J, INV };
 
 namespace instr
 {
diff --git a/inc/instrDTO.h b/inc/instrDTO.h
index 8249122..b6dec06 100644
--- a/inc/instrDTO.h
+++ b/inc/instrDTO.h
@@ -47,6 +47,10 @@ class InstrDTO
 	 * @return the type of the instruction
 	 */
 	Type get_type();
+	/**
+	 * @return the program counter at the time this instruction was fetched
+	 */
+	unsigned int get_pc();
 
 	/**
 	 * @param set hist key
@@ -72,11 +76,15 @@ class InstrDTO
 	 * @param the mnemonic of the instruction
 	 */
 	void set_mnemonic(Mnemonic);
-	
+
 	/**
 	 * @param the type of the instruction
 	 */
 	void set_type(Type);
+	/**
+	 * @param the program counter at the time this instruction was fetched
+	 */
+	void set_pc(unsigned int pc);
 
   private:
 	/**
@@ -100,11 +108,14 @@ class InstrDTO
 	 * The mnemonic of the operation.
 	 */
 	Mnemonic mnemonic;
-
 	/**
 	 * Type of the instruction
 	 */
 	Type type;
+	/**
+	 * The PC of the instruction
+	 */
+	unsigned int pc;
 };
 
 #endif /* INSTRDTO_H_INCLUDED */
diff --git a/inc/stage.h b/inc/stage.h
index 03048b0..51ab667 100644
--- a/inc/stage.h
+++ b/inc/stage.h
@@ -34,7 +34,7 @@ class Stage
 	 * ready to accept a new instruction object next cycle.
 	 * @return a DTO object containing the next instruction to be processed.
 	 *
-	 * Must set the status to STALLED when an operation completes.
+	 * Must set the status to WAIT when the current instruction is evicted..
 	 */
 	virtual InstrDTO *advance(Response p);
 
@@ -47,31 +47,33 @@ class Stage
 	 * @param the condition code to retrieve,
 	 */
 	bool get_condition(CC c);
-
 	/**
-	 * Sets the value of the PC register.
+	 * Sets the bit in the condition code register corresponding to `c`.
+	 * @param the condition code to set.
+	 * @param the truthy value to set it to.
 	 */
-	void set_pc(unsigned int pc);
+	void set_condition(CC c, bool v);
 
 	/**
 	 * Squashes the pipeline.
 	 */
 	void squash();
 
+	/**
+	 * The set of registers currently checked out.
+	 */
+	static std::deque<signed int> checked_out;
+
   protected:
 	/**
 	 * The function expected to do the majority of the work.
 	 *
-	 * Must set the status to OK when an operation is ready.
+	 * Must set the status to OK when an operation is done.
+	 * Must set the status to STALLED when an operation cannot be completed the
+	 * current cycle.
 	 */
 	virtual void advance_helper() = 0;
 	/**
-	 * Sets the bit in the condition code register corresponding to `c`.
-	 * @param the condition code to set.
-	 * @param the truthy value to set it to.
-	 */
-	void set_condition(CC c, bool v);
-	/**
 	 * Helper for `check_out`.
 	 * Returns true if r are not checked out, false otherwise.
 	 * @param a list of register numbers.
@@ -79,6 +81,12 @@ class Stage
 	 */
 	bool is_checked_out(signed int r);
 	/**
+	 * Stores `d` into the register indexed `v`.
+	 * @param the register number.
+	 * @param the value to store.
+	 */
+	void store_register(signed int v, signed int d);
+	/**
 	 * Returns the value of the register corresponding to `v`.
 	 * @param the register number.
 	 * @return the value in the associated register.
@@ -112,11 +120,6 @@ class Stage
 	 * The current clock cycle.
 	 */
 	static int clock_cycle;
-	// TODO fix this comment after writeback stage
-	/**
-	 * The set of registers currently checked out.
-	 */
-	static std::deque<signed int> checked_out;
 	/**
 	 * A pointer to the next stage in the pipeline.
 	 */
diff --git a/inc/wb.h b/inc/wb.h
index 62cef17..c4755ea 100644
--- a/inc/wb.h
+++ b/inc/wb.h
@@ -14,9 +14,27 @@ class WB : public Stage
 	 */
 	WB(Stage *next);
 	using Stage::advance;
-	
+
   private:
 	void advance_helper() override;
+	/**
+	 * Performs the actual work of storing into a register.
+	 */
+	void write_handler();
+	/**
+	 * Performs the actual work of processing a jump instruction.
+	 */
+	void jump_handler();
+	/**
+	 * @return true if the current instruction is an R or I type and is not a
+	 * STORE.
+	 */
+	bool should_write();
+	/**
+	 * @return true if the current instruction is a J type and is not a push.
+	 * STORE.
+	 */
+	bool should_jump();
 };
 
 #endif /* WB_H_INCLUDED */