1 files changed, 87 insertions, 1 deletions
diff --git a/src/sim/ex.cc b/src/sim/ex.cc
index 3a1e92c..fbf460f 100644
--- a/src/sim/ex.cc
+++ b/src/sim/ex.cc
@@ -1,9 +1,95 @@
 #include "ex.h"
 #include "accessor.h"
+#include "definitions.h"
 #include "instrDTO.h"
 #include "response.h"
 #include "stage.h"
+#include <unordered_map>
 
-EX::EX(Stage *stage) : Stage(stage) { this->id = EXEC; }
+// clang-format off
+#define INIT_INSTRUCTION(mnemonic, body)					\
+	{mnemonic, [this](signed int &s1, signed int &s2) { \
+		body; \
+	}}
+// clang-format on
+
+EX::EX(Stage *stage) : Stage(stage)
+{
+	this->id = EXEC;
+	instr_map = {
+
+		/* R type instructions */
+		INIT_INSTRUCTION(
+			ADD,
+			{
+				this->overflow_guard(s1, s2);
+				s1 = s1 + s2;
+			}),
+
+		INIT_INSTRUCTION(
+			SUB,
+			{
+				this->overflow_guard(s1, -s2);
+				s1 = s1 - s2;
+			}),
+
+		INIT_INSTRUCTION(MUL, {}),
+		INIT_INSTRUCTION(QUOT, {}),
+		INIT_INSTRUCTION(REM, {}),
+		INIT_INSTRUCTION(SFTR, {}),
+		INIT_INSTRUCTION(SFTL, {}),
+		INIT_INSTRUCTION(AND, {}),
+		INIT_INSTRUCTION(OR, {}),
+		INIT_INSTRUCTION(NOT, {}),
+		INIT_INSTRUCTION(XOR, {}),
+		INIT_INSTRUCTION(ADDV, {}),
+		INIT_INSTRUCTION(SUBV, {}),
+		INIT_INSTRUCTION(MULV, {}),
+		INIT_INSTRUCTION(DIVV, {}),
+		INIT_INSTRUCTION(CMP, {}),
+		INIT_INSTRUCTION(CEV, {}),
+
+		/* I type instructions */
+		INIT_INSTRUCTION(LOAD, {}),
+		INIT_INSTRUCTION(LOADV, {}),
+		INIT_INSTRUCTION(ADDI, {}),
+		INIT_INSTRUCTION(SUBI, {}),
+		INIT_INSTRUCTION(SFTRI, {}),
+		INIT_INSTRUCTION(SFTL, {}),
+		INIT_INSTRUCTION(ANDI, {}),
+		INIT_INSTRUCTION(ORI, {}),
+		INIT_INSTRUCTION(XORI, {}),
+		INIT_INSTRUCTION(STORE, {}),
+		INIT_INSTRUCTION(STOREV, {}),
+
+		/* J type instructions */
+		INIT_INSTRUCTION(JMP, {}),
+		INIT_INSTRUCTION(JRL, {}),
+		INIT_INSTRUCTION(JAL, {}),
+		INIT_INSTRUCTION(BEQ, {}),
+		INIT_INSTRUCTION(BGT, {}),
+		INIT_INSTRUCTION(BUF, {}),
+		INIT_INSTRUCTION(BOF, {}),
+		INIT_INSTRUCTION(PUSH, {}),
+		INIT_INSTRUCTION(POP, {}),
+
+		/* NOP */
+		INIT_INSTRUCTION(NOP, (void)s2; (void)s1;),
+	};
+}
 
 InstrDTO *EX::advance(Response p) { return nullptr; }
+
+void EX::overflow_guard(signed int a, signed int b)
+{
+	if (a >= 0 && b >= 0 && (a > MAX_INT - b)) {
+		this->set_condition(OF, true);
+		this->set_condition(UF, false);
+	} else if (a < 0 && b < 0 && (a < (-MAX_INT) - 1 - b)) {
+		this->set_condition(OF, false);
+		this->set_condition(UF, true);
+	} else {
+		this->set_condition(OF, false);
+		this->set_condition(UF, false);
+	}
+}