From 6557e7e623140871968776429d241570002a65f5 Mon Sep 17 00:00:00 2001
From: bd <bdunahu@operationnull.com>
Date: Sun, 30 Mar 2025 12:33:25 -0400
Subject: Setting condition code register, overflow guard

---
 inc/definitions.h |  6 ++++++
 inc/ex.h          | 18 ++++++++++++++++++
 inc/instr.h       |  1 -
 inc/stage.h       | 18 ++++++++++++++++++
 4 files changed, 42 insertions(+), 1 deletion(-)

(limited to 'inc')

diff --git a/inc/definitions.h b/inc/definitions.h
index 3238a8b..c81c4e3 100644
--- a/inc/definitions.h
+++ b/inc/definitions.h
@@ -76,6 +76,12 @@
  */
 #define OPCODE_SIZE 4
 
+/**
+ * The maximum value an integer can hold.
+ * The minimum is always this number plus one negated.
+ */
+#define MAX_INT 2147483647
+
 /**
  * Return the N least-significant bits from integer K using a bit mask
  * @param the integer to be parsed
diff --git a/inc/ex.h b/inc/ex.h
index 2ca8876..4edf873 100644
--- a/inc/ex.h
+++ b/inc/ex.h
@@ -3,6 +3,7 @@
 #include "instrDTO.h"
 #include "response.h"
 #include "stage.h"
+#include <unordered_map>
 
 class EX : public Stage
 {
@@ -15,6 +16,23 @@ class EX : public Stage
 	EX(Stage *next);
 
 	InstrDTO *advance(Response p) override;
+
+  private:
+	/**
+	 * Sets the (over|under)flow condition code if adding `a` and `b` results in
+	 * either.
+	 * @param the first operand
+	 * @param the second operand
+	 */
+	void overflow_guard(signed int a, signed int b);
+	/**
+	 * Maps each mnemonic to a function which carries out the instruction's base
+	 * logic.
+	 */
+	std::unordered_map<
+		Mnemonic,
+		std::function<void(signed int &s1, signed int &s2)>>
+		instr_map;
 };
 
 #endif /* EX_H_INCLUDED */
diff --git a/inc/instr.h b/inc/instr.h
index 08b4fd0..7fbb42b 100644
--- a/inc/instr.h
+++ b/inc/instr.h
@@ -49,7 +49,6 @@ namespace instr
 {
 // clang-format off
 	extern const std::unordered_map<unsigned int, Mnemonic> mnemonic_map;
-	extern const std::unordered_map<Mnemonic, std::function<void(signed int &s1, signed int &s2, signed int &s3)>> instr_map;
 // clang-format on
 } // namespace instr
 
diff --git a/inc/stage.h b/inc/stage.h
index 50c413a..c0dc6a8 100644
--- a/inc/stage.h
+++ b/inc/stage.h
@@ -9,6 +9,13 @@
 #include <deque>
 #include <memory>
 
+enum CC {
+	GT,
+	EQ,
+	UF,
+	OF,
+};
+
 class Stage
 {
   public:
@@ -30,6 +37,17 @@ class Stage
 	virtual InstrDTO *advance(Response p) = 0;
 
   protected:
+	/**
+	 * 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);
+	/**
+	 * Gets the bit in the condition code register correspondng to `c`.
+	 * @param the condition code to retrieve,
+	 */
+	bool get_condition(CC c);
 	/**
 	 * Helper for `check_out`.
 	 * Returns true if r are not checked out, false otherwise.
-- 
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