Fix a lot of pipeline bugs

1 files changed, 48 insertions, 27 deletions

diff --git a/src/sim/wb.cc b/src/sim/wb.cc
index 276d1d0..01768e8 100644
--- a/src/sim/wb.cc
+++ b/src/sim/wb.cc
@@ -8,33 +8,54 @@ WB::WB(Stage *stage) : Stage(stage) { this->id = WRITE; }
 
 void WB::advance_helper()
 {
-	if (this->curr_instr->get_type() == R ||
-		this->curr_instr->get_type() == I) {
-		if (this->checked_out.size() > 0) {
-			signed int reg = this->checked_out.front();
-			this->checked_out.pop_front();
-			if (reg >= GPR_NUM) {
-				// TODO: handle vector instructions
-			} else {
-				if (this->curr_instr->get_mnemonic() != STORE &&
-					this->curr_instr->get_mnemonic() != STOREV) {
-					this->gprs[reg] = this->curr_instr->get_s1();
-				}
-			}
-		}
-	} else if (this->curr_instr->get_type() == J) {
-		// TODO:handle push pop
-		// branch taken
-		if (this->pc != this->curr_instr->get_s1()) {
-			if (this->curr_instr->get_mnemonic() == JAL) {
-				// set link register to next instruction
-				this->gprs[1] = this->pc + 1;
-			}
-			this->pc = this->curr_instr->get_s1();
-			// clear pending registers and squash pipeline
-			this->checked_out = {};
-			this->next->squash();
-		}
+	if (this->curr_instr->get_mnemonic() != NOP &&
+		this->curr_instr->get_type() != INV) {
+		if (this->should_write())
+			this->write_handler();
+		else if (this->should_jump())
+			this->jump_handler();
 	}
 	this->status = OK;
 }
+
+void WB::write_handler()
+{
+	signed int reg;
+
+	if (this->checked_out.size() < 1)
+		throw std::runtime_error("instruction tried to pop a register out of "
+								 "an empty queue during writeback.");
+
+	reg = this->checked_out.front();
+	this->checked_out.pop_front();
+	this->store_register(reg, this->curr_instr->get_s1());
+}
+
+void WB::jump_handler()
+{
+	if (this->curr_instr->get_s1() > 0) {
+		if (this->curr_instr->get_mnemonic() == JAL)
+			this->gprs[1] = this->pc + 1;
+		this->pc = this->curr_instr->get_s1();
+		this->checked_out = {};
+		this->next->squash();
+	}
+}
+
+bool WB::should_jump()
+{
+	Type t;
+
+	t = this->curr_instr->get_type();
+	return t == J;
+}
+
+bool WB::should_write()
+{
+	Mnemonic m;
+	Type t;
+
+	m = this->curr_instr->get_mnemonic();
+	t = this->curr_instr->get_type();
+	return (t == R || t == I) && (m != STORE && m != STOREV);
+}