From ba535e24e0aaf2fcefa1196dc4d12ad241f349d3 Mon Sep 17 00:00:00 2001
From: Richard Qin <richard.qin.x@gmail.com>
Date: Sun, 15 Mar 2026 23:30:38 +0800
Subject: Add and test alu unit

---
 rv64cpu/tb/unit/tb_alu.cc | 67 +++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 67 insertions(+)
 create mode 100644 rv64cpu/tb/unit/tb_alu.cc

(limited to 'rv64cpu/tb/unit/tb_alu.cc')

diff --git a/rv64cpu/tb/unit/tb_alu.cc b/rv64cpu/tb/unit/tb_alu.cc
new file mode 100644
index 0000000..b783815
--- /dev/null
+++ b/rv64cpu/tb/unit/tb_alu.cc
@@ -0,0 +1,67 @@
+#include "Valu.h"
+#include <cassert>
+#include <cstdint>
+#include <iostream>
+#include <verilated.h>
+
+enum AluOp {
+    ALU_ADD  = 0b0000,
+    ALU_SUB  = 0b1000,
+    ALU_SLL  = 0b0001,
+    ALU_SLT  = 0b0010,
+    ALU_SLTU = 0b0011,
+    ALU_XOR  = 0b0100,
+    ALU_SRL  = 0b0101,
+    ALU_SRA  = 0b1101,
+    ALU_OR   = 0b0110,
+    ALU_AND  = 0b0111
+};
+
+void test_alu(Valu* alu, uint8_t op, uint64_t rs1, uint64_t rs2, uint64_t expected, const char* test_name) {
+    alu->alu_op = op;
+    alu->rs1_val = rs1;
+    alu->rs2_val = rs2;
+
+    alu->eval();
+    
+    if (alu->alu_res == expected) {
+        std::cout << "\033[32m";
+        std::cout << "[PASS] " << test_name << " | " 
+                  << rs1 << " op " << rs2 << " = " << expected << std::endl;
+        std::cout << "\033[0m";
+    } else {
+        std::cout << "\033[31m";
+        std::cerr << "[FAIL] " << test_name << " | " 
+                  << "Expected: " << expected << ", Got: " << alu->alu_res << std::endl;
+        std::cout << "\033[0m";
+        assert(false);
+    }
+}
+
+int main(int argc, char** argv) {
+    Verilated::commandArgs(argc, argv);
+    Valu* alu = new Valu;
+    
+    std::cout << "Running ALU Unit Test ..." << std::endl;
+    
+    test_alu(alu, ALU_ADD, 100, 50, 150, "ADD_Positive");
+    test_alu(alu, ALU_SUB, 100, 50, 50,  "SUB_Positive");
+
+    test_alu(alu, ALU_ADD, (uint64_t)-5, 10, 5, "ADD_Negative");
+
+    test_alu(alu, ALU_AND, 0xFF00, 0x0F0F, 0x0F00, "AND_Mask");
+    test_alu(alu, ALU_XOR, 0xAAAA, 0xFFFF, 0x5555, "XOR_Invert");
+
+    test_alu(alu, ALU_SLL, 1, 10, 1024, "SLL_By_10");
+
+    uint64_t minus_one = (uint64_t)-1;
+    uint64_t five = 5;
+    
+    test_alu(alu, ALU_SLTU, minus_one, five, 0, "SLTU (Unsigned: -1 < 5 is False)");
+    test_alu(alu, ALU_SLT,  minus_one, five, 1, "SLT  (Signed: -1 < 5 is True)");
+
+    std::cout << "All tests passed!" << std::endl;
+
+    delete alu;
+    return 0;
+}
\ No newline at end of file
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