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// Richard CPU
// Copyright (C) 2026 Richard Qin
// 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/>.
// File path: tb/unit/tb_branch.cc
// Description: Branch Unit test
#include <iostream>
#include <iomanip>
#include <cstdint>
#include <cassert>
#include <verilated.h>
#include "Vbranch_unit.h"
// Enums must match rv64_pkg::branch_op_t
enum BranchOp {
BRANCH_EQ = 0b000,
BRANCH_NE = 0b001,
BRANCH_LT = 0b100,
BRANCH_GE = 0b101,
BRANCH_LTU = 0b110,
BRANCH_GEU = 0b111
};
void test_branch(Vbranch_unit* dut, uint8_t is_branch, uint8_t op, uint64_t a, uint64_t b, uint8_t expected, const char* name) {
dut->is_branch = is_branch;
dut->branch_op = op;
dut->operand_a = a;
dut->operand_b = b;
dut->eval();
if (dut->branch_taken == expected) {
std::cout << "\033[32m[PASS] " << name << " | Expected: " << (int)expected << " Got: " << (int)dut->branch_taken << "\033[0m" << std::dec << std::endl;
} else {
std::cout << "\033[31m[FAIL] " << name << " | Expected: " << (int)expected << " Got: " << (int)dut->branch_taken << "\033[0m" << std::endl;
assert(false);
}
}
int main(int argc, char** argv) {
Verilated::commandArgs(argc, argv);
Vbranch_unit* dut = new Vbranch_unit;
std::cout << "----------------------------------" << std::endl;
std::cout << " Branch Unit Test" << std::endl;
std::cout << "----------------------------------" << std::endl;
// --- Not a branch ---
test_branch(dut, 0, BRANCH_EQ, 10, 10, 0, "Not_A_Branch");
// --- BEQ / BNE ---
test_branch(dut, 1, BRANCH_EQ, 10, 10, 1, "BEQ_Equal");
test_branch(dut, 1, BRANCH_EQ, 10, 20, 0, "BEQ_Not_Equal");
test_branch(dut, 1, BRANCH_NE, 10, 20, 1, "BNE_Not_Equal");
test_branch(dut, 1, BRANCH_NE, 10, 10, 0, "BNE_Equal");
uint64_t minus_one = (uint64_t)-1; // 0xFFFFFFFFFFFFFFFF
uint64_t one = 1;
// --- BLT / BGE (Signed) ---
// -1 is less than 1 (Signed)
test_branch(dut, 1, BRANCH_LT, minus_one, one, 1, "BLT_Signed_Negative_vs_Positive");
test_branch(dut, 1, BRANCH_GE, minus_one, one, 0, "BGE_Signed_Negative_vs_Positive");
// 1 is greater than -1 (Signed)
test_branch(dut, 1, BRANCH_LT, one, minus_one, 0, "BLT_Signed_Positive_vs_Negative");
test_branch(dut, 1, BRANCH_GE, one, minus_one, 1, "BGE_Signed_Positive_vs_Negative");
// Equal signed
test_branch(dut, 1, BRANCH_LT, minus_one, minus_one, 0, "BLT_Signed_Equal");
test_branch(dut, 1, BRANCH_GE, minus_one, minus_one, 1, "BGE_Signed_Equal");
// --- BLTU / BGEU (Unsigned) ---
// 0xFFFFFFFFFFFFFFFF is NOT less than 1 (Unsigned)
test_branch(dut, 1, BRANCH_LTU, minus_one, one, 0, "BLTU_Unsigned_Max_vs_1");
// 0xFFFFFFFFFFFFFFFF is greater than or equal to 1 (Unsigned)
test_branch(dut, 1, BRANCH_GEU, minus_one, one, 1, "BGEU_Unsigned_Max_vs_1");
// Equal unsigned
test_branch(dut, 1, BRANCH_LTU, minus_one, minus_one, 0, "BLTU_Unsigned_Equal");
test_branch(dut, 1, BRANCH_GEU, minus_one, minus_one, 1, "BGEU_Unsigned_Equal");
std::cout << "----------------------------------" << std::endl;
std::cout << "\033[32mAll tests passed!\033[0m" << std::endl;
std::cout << "----------------------------------" << std::endl;
delete dut;
return 0;
}
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