1 files changed, 75 insertions, 0 deletions
diff --git a/src/wb.cc b/src/wb.cc
new file mode 100644
index 0000000..55591b6
--- /dev/null
+++ b/src/wb.cc
@@ -0,0 +1,75 @@
+// Simulator for the RISC-V[ECTOR] mini-ISA
+// Copyright (C) 2025 Siddarth Suresh
+// Copyright (C) 2025 bdunahu
+
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+#include "wb.h"
+#include "instrDTO.h"
+#include "response.h"
+#include "stage.h"
+#include <array>
+#include <algorithm>
+
+void WB::advance_helper()
+{
+	if (this->curr_instr->get_mnemonic() != NOP &&
+		this->curr_instr->get_type() != INV) {
+		if (this->curr_instr->get_checked_out() > 0)
+			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.");
+
+	if (this->curr_instr->get_mnemonic() == POP) {
+		// POP performs a second register write
+		reg = this->checked_out.front();
+		this->checked_out.pop_front();
+		this->store_register(reg, this->curr_instr->get_s3());
+	}
+
+	this->checked_out.pop_front();
+	reg = this->curr_instr->get_checked_out();
+	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->curr_instr->get_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;
+}