From 5beea0c476101ec7b122f3b2181d92ce096492fb Mon Sep 17 00:00:00 2001
From: bd <bdunahu@operationnull.com>
Date: Sat, 10 May 2025 15:30:29 -0400
Subject: Further small simplifications

---
 inc/id.h  |  9 +++++----
 src/id.cc | 27 +++++++++++++--------------
 2 files changed, 18 insertions(+), 18 deletions(-)

diff --git a/inc/id.h b/inc/id.h
index c1928ed..5fda2b4 100644
--- a/inc/id.h
+++ b/inc/id.h
@@ -60,7 +60,7 @@ class ID : public Stage
 	 * @param the resulting third field, which varies per type.
 	 * @param the resulting mnemonic.
 	 */
-	void get_instr_fields(signed int &s1);
+	void get_instr_fields(signed int instr_bits);
 	void decode_R_type(signed int &s1);
 	void decode_I_type(signed int &s1);
 	void decode_J_type(signed int &s1);
@@ -96,10 +96,11 @@ class ID : public Stage
 	/**
 	 * Facilitates register checkout and data hazard management.
 	 * It does this by checking that the register passed in is not currently
-	 * checked out. If true, then replaces reg with the value of the register and
-	 * returns OK. If false, returns STALLED.
+	 * checked out. If true, then sets `result' with the value of the register
+	 * and returns OK. If false, returns STALLED.
 	 *
-	 * @param the registers number, to be dereferenced.
+	 * @param the registers number
+	 * @param the dereferenced register value
 	 * @return OK if `reg` is not checked out, STALLED otherwise.
 	 */
 	template <typename T> Response read_guard(int reg, T &result)
diff --git a/src/id.cc b/src/id.cc
index bc6b873..43975fb 100644
--- a/src/id.cc
+++ b/src/id.cc
@@ -24,37 +24,35 @@
 
 void ID::advance_helper()
 {
-	signed int s1;
-
 	if (this->curr_instr->mnemonic == NOP)
 		this->status = OK;
 	else {
 		// instuction in bits in s1
-		s1 = this->curr_instr->slot_A;
-		get_instr_fields(s1);
+		get_instr_fields(this->curr_instr->slot_A);
 	}
 }
 
-void ID::get_instr_fields(signed int &s1)
+void ID::get_instr_fields(signed int instr_bits)
 {
 	unsigned int type;
 	Mnemonic m;
-	this->split_instr(s1, type, m);
+	this->split_instr(instr_bits, type, m);
 	this->curr_instr->mnemonic = m;
 	switch (type) {
 	case 0b00:
-		this->decode_R_type(s1);
+		this->decode_R_type(instr_bits);
 		break;
 	case 0b01:
-		this->decode_I_type(s1);
+		this->decode_I_type(instr_bits);
 		break;
 	case 0b10:
-		this->decode_J_type(s1);
+		this->decode_J_type(instr_bits);
 		break;
 	case 0b11:
-		// not defined, m = NOP
+		this->curr_instr->mnemonic = NOP;
 		this->status = OK;
 	}
+
 }
 
 void ID::split_instr(signed int &raw, unsigned int &type, Mnemonic &m)
@@ -233,9 +231,10 @@ void ID::decode_J_type(signed int &s1)
 		s2 = s1; // source
 		s3 = 2;	 // stack pointer
 		s1 = -1; // increment amount
-		r1 = this->read_guard<signed int>(s2, s2);
+
 		this->curr_instr->operands.integer.slot_one = s1;
-		this->curr_instr->operands.integer.slot_two = s2;
+		r1 = this->read_guard<signed int>(
+			s2, this->curr_instr->operands.integer.slot_two);
 		r2 = (this->is_checked_out(s3)) ? STALLED
 										: OK; // we read the stack pointer
 		if (r1 == OK && r2 == OK) {
@@ -265,9 +264,9 @@ void ID::decode_J_type(signed int &s1)
 		s1 = 1; // link register
 		[[fallthrough]];
 	default:
-		this->status = this->read_guard<signed int>(s1, s1);
+		this->status = this->read_guard<signed int>(
+			s1, this->curr_instr->operands.integer.slot_one);
 		if (this->status == OK) {
-			this->curr_instr->operands.integer.slot_one = s1;
 			this->curr_instr->operands.integer.slot_two = s2;
 			this->curr_instr->operands.integer.slot_three = s3;
 		}
-- 
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