1 files changed, 78 insertions, 0 deletions
diff --git a/src/wb.cc b/src/wb.cc
new file mode 100644
index 0000000..cd24c6a
--- /dev/null
+++ b/src/wb.cc
@@ -0,0 +1,78 @@
+// 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 <algorithm>
+#include <array>
+
+void WB::advance_helper()
+{
+	if (this->curr_instr->mnemonic != NOP) {
+		if (this->curr_instr->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->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->operands.integer.slot_three);
+	}
+
+	this->checked_out.pop_front();
+	reg = this->curr_instr->checked_out;
+	this->store_register(reg, this->curr_instr->operands.integer.slot_one);
+}
+
+void WB::jump_handler()
+{
+	if (this->curr_instr->operands.integer.slot_one > 0) {
+		if (this->curr_instr->mnemonic == JAL)
+			this->gprs[1] = this->curr_instr->slot_B + 1;
+		;
+		this->pc = this->curr_instr->operands.integer.slot_one;
+		this->checked_out = {};
+		this->next->squash();
+	}
+}
+
+// TODO clean this up...
+bool WB::should_jump()
+{
+	vector<Mnemonic> Js = {JMP, JRL, JAL, BEQ, BGT, BUF, BOF, PUSH, POP, RET};
+
+	if (find(Js.begin(), Js.end(), this->curr_instr->mnemonic) != Js.end())
+		return true;
+	else
+		return false;
+}