Setting condition code register, overflow guard

3 files changed, 99 insertions, 30 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);
+	}
+}
diff --git a/src/sim/instr.cc b/src/sim/instr.cc
index 08edf5e..e614de5 100644
--- a/src/sim/instr.cc
+++ b/src/sim/instr.cc
@@ -3,36 +3,8 @@
 #include <map>
 #include <unordered_map>
 
-// clang-format off
-#define INIT_INSTRUCTION(mnemonic, body) \
-	{mnemonic, [](signed int &s1, signed int &s2, signed int &s3) { \
-		body; \
-	}}
-// clang-format on
-
 namespace instr
 {
-// clang-format off
-const std::unordered_map<Mnemonic, std::function<void(signed int &s1, signed int &s2, signed int &s3)>>
-	// clang-format on
-	instr_map = {
-
-		/* R type instructions */
-		// TODO these need to be WRAPPED with a function that sets overflow.
-		// future note to self, if these are more than 2 lines each, you're
-		// doing it wrong
-		INIT_INSTRUCTION(ADD, s3 = s1 + s2;),
-		INIT_INSTRUCTION(SUB, s3 = s1 - s2;),
-
-		/* I type instructions */
-
-		/* J type instructions */
-
-		/* NOP */
-		INIT_INSTRUCTION(NOP, (void)s3; (void)s2; (void)s1;),
-
-};
-
 const std::unordered_map<unsigned int, Mnemonic> mnemonic_map = {
 	{0b0000100, ADD},	 {0b0001000, SUB},	 {0b0001100, MUL},
 	{0b0010000, QUOT},	 {0b0010100, REM},	 {0b0011000, SFTR},
@@ -48,6 +20,5 @@ const std::unordered_map<unsigned int, Mnemonic> mnemonic_map = {
 	{0b0001010, JRL},	 {0b0001110, JAL},	 {0b0010010, BEQ},
 	{0b0010110, BGT},	 {0b0011010, BUF},	 {0b0011110, BOF},
 	{0b0100010, PUSH},	 {0b0100110, POP},
-
 };
 } // namespace instr
diff --git a/src/sim/stage.cc b/src/sim/stage.cc
index 62a7fd6..d8c882a 100644
--- a/src/sim/stage.cc
+++ b/src/sim/stage.cc
@@ -21,6 +21,18 @@ Storage *Stage::storage;
 bool Stage::is_pipelined;
 int Stage::clock_cycle;
 
+void Stage::set_condition(CC c, bool v)
+{
+	if (v)
+		this->gprs[3] = this->gprs[3] & 1 << c;
+	else
+		this->gprs[3] = this->gprs[3] & ~(1 << c);
+}
+
+bool Stage::get_condition(CC c) {
+	return (this->gprs[3] >> c) & 1;
+}
+
 signed int Stage::dereference_register(signed int v)
 {
 	signed int r;