From ab6a21ae1099bff120111b8a9dcfa50c9fcad5a1 Mon Sep 17 00:00:00 2001 From: Richard Qin Date: Thu, 19 Mar 2026 03:16:03 +0800 Subject: Trap Control unit and tests --- rv64cpu/tb/unit/tb_trap_ctrl.cc | 192 ++++++++++++++++++++++++++++++++++++++++ 1 file changed, 192 insertions(+) create mode 100644 rv64cpu/tb/unit/tb_trap_ctrl.cc (limited to 'rv64cpu/tb/unit') diff --git a/rv64cpu/tb/unit/tb_trap_ctrl.cc b/rv64cpu/tb/unit/tb_trap_ctrl.cc new file mode 100644 index 0000000..142d743 --- /dev/null +++ b/rv64cpu/tb/unit/tb_trap_ctrl.cc @@ -0,0 +1,192 @@ +// 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 . + +// File path: tb/unit/tb_trap_ctrl.cc +// Description: Standalone unit test for trap_ctrl exception/interrupt control logic + +#include +#include +#include +#include + +#include "Vtrap_ctrl.h" + +namespace { +constexpr uint64_t EXC_INST_ILLEGAL = 2ULL; +constexpr uint64_t EXC_ECALL_FROM_S = 9ULL; +constexpr uint64_t EXC_LOAD_PAGE_FAULT= 13ULL; + +constexpr uint64_t INT_M_SOFTWARE = 3ULL; +constexpr uint64_t INT_M_TIMER = 7ULL; +constexpr uint64_t INT_M_EXTERNAL = 11ULL; + +constexpr uint64_t INTERRUPT_BIT = 1ULL << 63; +constexpr uint64_t PRIV_MODE_U = 0ULL; +constexpr uint64_t PRIV_MODE_S = 1ULL; +constexpr uint64_t PRIV_MODE_M = 3ULL; + +void drive_defaults(Vtrap_ctrl* dut) { + dut->wb_pc = 0; + dut->trap_illegal_instr = 0; + dut->trap_is_ecall = 0; + dut->trap_is_ebreak = 0; + dut->trap_is_mret = 0; + dut->trap_is_sret = 0; + dut->trap_load_fault = 0; + dut->trap_store_fault = 0; + dut->trap_instr_page_fault = 0; + dut->trap_load_page_fault = 0; + dut->trap_store_page_fault = 0; + dut->trap_bad_addr = 0; + dut->trap_bad_instr = 0; + + dut->ext_timer_int = 0; + dut->ext_software_int = 0; + dut->ext_external_int = 0; + + dut->csr_mstatus_mie = 0; + dut->csr_mtvec = 0x800ULL; + dut->csr_stvec = 0x400ULL; + dut->csr_mepc = 0x1000ULL; + dut->csr_sepc = 0x2000ULL; + dut->csr_medeleg = 0ULL; + dut->csr_mideleg = 0ULL; + dut->csr_priv_mode = PRIV_MODE_M; + + dut->eval(); +} + +int pass_count = 0; + +void check(bool cond, const char* name) { + if (cond) { + std::cout << "\033[32m[PASS] " << name << "\033[0m" << std::endl; + pass_count++; + } else { + std::cout << "\033[31m[FAIL] " << name << "\033[0m" << std::endl; + assert(false); + } +} +} // namespace + +int main(int argc, char** argv) { + Verilated::commandArgs(argc, argv); + Vtrap_ctrl* dut = new Vtrap_ctrl; + + std::cout << "----------------------------------\n"; + std::cout << " trap_ctrl Testbench\n"; + std::cout << "----------------------------------\n"; + + // --------------------------------------------------------------------- + // 1) Synchronous exceptions (illegal instruction, ecall, page fault) + // --------------------------------------------------------------------- + drive_defaults(dut); + dut->csr_priv_mode = PRIV_MODE_M; + dut->csr_mtvec = 0x880ULL; + dut->wb_pc = 0x1234ULL; + dut->trap_bad_instr = 0xDEADBEEFu; + dut->trap_illegal_instr = 1; + dut->eval(); + check(dut->trap_trigger, "IllegalInst_TriggersTrap"); + check(dut->trap_mcause == EXC_INST_ILLEGAL, "IllegalInst_Mcause"); + check(dut->trap_mtval == 0xDEADBEEFULL, "IllegalInst_Mtval"); + check(dut->trap_mepc == 0x1234ULL, "IllegalInst_Mepc"); + check(!dut->trap_to_s_mode, "IllegalInst_NoDelegation"); + check(dut->trap_next_pc == 0x880ULL, "IllegalInst_JumpsToMtvec"); + + drive_defaults(dut); + dut->csr_priv_mode = PRIV_MODE_S; + dut->csr_mtvec = 0x440ULL; + dut->wb_pc = 0x5678ULL; + dut->trap_is_ecall = 1; + dut->eval(); + check(dut->trap_trigger, "EcallS_TriggersTrap"); + check(dut->trap_mcause == EXC_ECALL_FROM_S, "EcallS_Mcause"); + check(dut->trap_mtval == 0ULL, "EcallS_MtvalZero"); + check(dut->trap_next_pc == 0x440ULL, "EcallS_JumpsToMtvec"); + + drive_defaults(dut); + dut->trap_load_page_fault = 1; + dut->trap_bad_addr = 0xBADC0FFEE0ULL; + dut->eval(); + check(dut->trap_mcause == EXC_LOAD_PAGE_FAULT, "PageFault_Mcause"); + check(dut->trap_mtval == 0xBADC0FFEE0ULL, "PageFault_Mtval"); + + // --------------------------------------------------------------------- + // 2) Interrupt priority + delegation to supervisor + // --------------------------------------------------------------------- + drive_defaults(dut); + dut->csr_mstatus_mie = 1; + dut->csr_priv_mode = PRIV_MODE_M; + dut->csr_mtvec = 0x300ULL | 0x1ULL; // vectored mode + dut->wb_pc = 0x4000ULL; + dut->ext_timer_int = 1; + dut->ext_software_int = 1; + dut->ext_external_int = 1; + dut->eval(); + const uint64_t expected_vectored_pc = 0x300ULL + (INT_M_EXTERNAL << 2); + check(dut->trap_trigger, "InterruptPriority_Triggers"); + check(dut->trap_mcause == (INTERRUPT_BIT | INT_M_EXTERNAL), "InterruptPriority_Mcause"); + check(dut->trap_mtval == 0ULL, "InterruptPriority_MtvalZero"); + check(dut->trap_next_pc == expected_vectored_pc, "InterruptPriority_VectoredJump"); + + drive_defaults(dut); + dut->csr_mstatus_mie = 0; + dut->ext_external_int = 1; + dut->eval(); + check(!dut->trap_trigger, "InterruptMasked_NoTrigger"); + + drive_defaults(dut); + dut->csr_priv_mode = PRIV_MODE_S; + dut->csr_mstatus_mie = 1; + dut->csr_stvec = 0x880ULL | 0x1ULL; // vectored supervisor mode + dut->csr_mideleg = (1ULL << INT_M_TIMER); + dut->wb_pc = 0xABCDULL; + dut->ext_timer_int = 1; + dut->eval(); + const uint64_t expected_sv_pc = 0x880ULL + (INT_M_TIMER << 2); + check(dut->trap_to_s_mode, "InterruptDelegation_ToSupervisor"); + check(dut->trap_next_pc == expected_sv_pc, "InterruptDelegation_UsesStvec"); + check(dut->trap_mcause == (INTERRUPT_BIT | INT_M_TIMER), "InterruptDelegation_Mcause"); + + // --------------------------------------------------------------------- + // 3) MRET/SRET redirect without new traps + // --------------------------------------------------------------------- + drive_defaults(dut); + dut->csr_mepc = 0xCAFEBABEULL; + dut->trap_is_mret = 1; + dut->eval(); + check(dut->mret_en, "Mret_PathEnabled"); + check(dut->trap_next_pc == 0xCAFEBABEULL, "Mret_RestoresMepc"); + check(dut->trap_flush_req && dut->trap_pc_sel, "Mret_ForcesFlush"); + check(!dut->trap_trigger, "Mret_NoTrapOverlap"); + + drive_defaults(dut); + dut->csr_priv_mode = PRIV_MODE_S; + dut->csr_sepc = 0x13579BDFULL; + dut->trap_is_sret = 1; + dut->eval(); + check(dut->sret_en, "Sret_PathEnabled"); + check(dut->trap_next_pc == 0x13579BDFULL, "Sret_RestoresSepc"); + check(dut->trap_flush_req && dut->trap_pc_sel, "Sret_ForcesFlush"); + + std::cout << "----------------------------------\n"; + std::cout << "All " << pass_count << " trap_ctrl tests passed!\n"; + std::cout << "----------------------------------\n"; + + delete dut; + return 0; +} -- cgit v1.2.3