Files
ppsspp/Core/MIPS/IR/IRJit.cpp
T
Henrik RydgårdandClaude Opus 5.5 5a9cbf007c CPU: Pass the MIPSState explicitly where it was already at hand
The JIT backends' calls out of generated code (the MIPS and IR interpreter
fallbacks, and the bad address report) now take the state the backend was
built for instead of reading currentMIPS. Likewise the interpreter's tick
check, the IR dispatcher's Advance, and a couple of debugger helpers.

MIPSState::InitRegisters() no longer sets currentMIPS; the boot paths set it.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
2026-10-20 09:47:48 +02:00

680 lines
20 KiB
C++

// Copyright (c) 2012- PPSSPP Project.
// 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, version 2.0 or later versions.
// 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 2.0 for more details.
// A copy of the GPL 2.0 should have been included with the program.
// If not, see http://www.gnu.org/licenses/
// Official git repository and contact information can be found at
// https://github.com/hrydgard/ppsspp and http://www.ppsspp.org/.
#include "ppsspp_config.h"
#include <set>
#include <algorithm>
#include "ext/xxhash.h"
#include "Common/Profiler/Profiler.h"
#include "Common/Log.h"
#include "Common/Serialize/Serializer.h"
#include "Common/StringUtils.h"
#include "Common/File/FileUtil.h"
#include "Core/Config.h"
#include "Core/Core.h"
#include "Core/CoreTiming.h"
#include "Core/Debugger/SymbolMap.h"
#include "Core/HLE/ReplaceTables.h"
#include "Core/HLE/sceKernelMemory.h"
#include "Core/MemMap.h"
#include "Core/MIPS/MIPS.h"
#include "Core/MIPS/MIPSCodeUtils.h"
#include "Core/MIPS/Interpreter.h"
#include "Core/MIPS/MIPSTables.h"
#include "Core/MIPS/IR/IRRegCache.h"
#include "Core/MIPS/IR/IRInterpreter.h"
#include "Core/MIPS/IR/IRJit.h"
#include "Core/MIPS/IR/IRNativeCommon.h"
#include "Core/MIPS/JitCommon/JitCommon.h"
#include "Core/Reporting.h"
#include "Common/TimeUtil.h"
#include "Core/MIPS/MIPSTracer.h"
namespace MIPSComp {
IRJit::IRJit(MIPSState *mipsState, bool actualJit) : frontend_(mipsState->HasDefaultPrefix()), mips_(mipsState), blocks_(actualJit) {
// u32 size = 128 * 1024;
InitIR();
compileToNative_ = actualJit;
// If this IRJit instance will be used to drive a "JIT using IR", don't optimize for interpretation.
jo.optimizeForInterpreter = !actualJit;
IROptions opts{};
opts.disableFlags = g_Config.uJitDisableFlags;
#if PPSSPP_ARCH(RISCV64)
// Assume RISC-V always has very slow unaligned memory accesses.
opts.unalignedLoadStore = false;
opts.unalignedLoadStoreVec4 = true;
opts.preferVec4 = cpu_info.RiscV_V;
#elif PPSSPP_ARCH(ARM) || PPSSPP_ARCH(ARM64)
opts.unalignedLoadStore = (opts.disableFlags & (uint32_t)JitDisable::LSU_UNALIGNED) == 0;
opts.unalignedLoadStoreVec4 = true;
opts.preferVec4 = true;
#else
opts.unalignedLoadStore = (opts.disableFlags & (uint32_t)JitDisable::LSU_UNALIGNED) == 0;
// TODO: Could allow on x86 pretty easily...
opts.unalignedLoadStoreVec4 = false;
opts.preferVec4 = true;
#endif
opts.optimizeForInterpreter = jo.optimizeForInterpreter;
// The IR interpreter, and the backends with a routine for it.
#if PPSSPP_ARCH(ARM64)
opts.vfpuMultiDot = true;
opts.moreVec4Ops = true;
#elif PPSSPP_ARCH(RISCV64) || PPSSPP_ARCH(LOONGARCH64)
opts.vfpuMultiDot = !actualJit;
opts.moreVec4Ops = true;
#else
opts.vfpuMultiDot = !actualJit;
opts.moreVec4Ops = !actualJit;
#endif
opts.continueBranches = IR_CONTINUE_BRANCHES;
frontend_.SetOptions(opts);
profiling_ = !g_Config.sJitProfileFile.empty();
blocks_.SetProfiling(profiling_ && !actualJit);
}
IRJit::~IRJit() {
}
void IRJit::DoState(PointerWrap &p) {
if (frontend_.DoState(p)) {
ClearCache();
}
}
void IRJit::UpdateFCR31() {
if (frontend_.UpdateFCR31(mips_->fcr31)) {
mips_->ClearJitCacheDeferred();
}
}
void IRJit::ClearCache() {
INFO_LOG(Log::JIT, "IRJit: Clearing the block cache!");
if (profiling_)
WriteProfileReport();
blocks_.Clear();
}
void IRJit::FlushProfile() {
if (profiling_)
WriteProfileReport();
}
void IRJit::WriteProfileReport() {
int64_t totalNanos = 0;
std::vector<int> hot;
for (int i = 0; i < blocks_.GetNumBlocks(); ++i) {
const IRBlock *b = blocks_.GetBlock(i);
if (b->profileStats_.executions == 0)
continue;
totalNanos += b->profileStats_.totalNanos;
hot.push_back(i);
}
// Skip the near-empty profiles of a cache cleared while booting or loading a state.
if (totalNanos < 100'000'000)
return;
std::sort(hot.begin(), hot.end(), [&](int a, int b) {
return blocks_.GetBlock(a)->profileStats_.totalNanos > blocks_.GetBlock(b)->profileStats_.totalNanos;
});
FILE *f = File::OpenCFile(Path(g_Config.sJitProfileFile), "a");
if (!f)
return;
fprintf(f, "IR interpreter profile: %.3f s in %d blocks\n\n", totalNanos * 1e-9, (int)hot.size());
for (int rank = 0; rank < (int)hot.size() && rank < 40; ++rank) {
const int blockNum = hot[rank];
const IRBlock *b = blocks_.GetBlock(blockNum);
const JitBlockProfileStats &stats = b->profileStats_;
const std::string label = g_symbolMap ? g_symbolMap->GetDescription(b->GetOriginalStart()) : "";
fprintf(f, "#%d %.2f%% block %d at %08x %s: %lld runs, %.1f ns/run\n", rank + 1, 100.0 * stats.totalNanos / totalNanos, blockNum,
b->GetOriginalStart(), label.c_str(), (long long)stats.executions, (double)stats.totalNanos / stats.executions);
const IRInst *inst = blocks_.GetBlockInstructionPtr(*b);
for (int i = 0; i < b->GetNumIRInstructions(); ++i) {
char temp[256];
DisassembleIR(temp, sizeof(temp), inst[i]);
fprintf(f, " %s\n", temp);
}
fprintf(f, "\n");
}
fclose(f);
for (int blockNum : hot)
blocks_.GetBlock(blockNum)->profileStats_ = JitBlockProfileStats{};
}
void IRJit::InvalidateCacheAt(u32 em_address, int length) {
std::vector<int> numbers = blocks_.FindInvalidatedBlockNumbers(em_address, length);
if (numbers.empty()) {
return;
}
DEBUG_LOG(Log::JIT, "Invalidating IR block cache at %08x (%d bytes): %d blocks", em_address, length, (int)numbers.size());
invalidations_++;
invalidatedBlocks_ += (int)numbers.size();
for (int block_num : numbers) {
// TODO: We are invalidating a lot of blocks that are already invalid (yu gi oh).
InvalidateBlock(block_num);
}
}
void IRJit::InvalidateBlock(int block_num) {
IRBlock *block = blocks_.GetBlock(block_num);
// If we're a native JIT (IR->JIT, not just IR interpreter), we write native offsets into the blocks.
int cookie = compileToNative_ ? block->GetNativeOffset() : block->GetIRArenaOffset();
// Before Destroy, which forgets the block's address. Blocks linked to it jump straight in.
InvalidateNativeBlock(&blocks_, block_num);
blocks_.RemoveBlockFromPageLookup(block_num);
block->Destroy(cookie);
}
void IRJit::InvalidateCacheExcept(const std::vector<std::pair<u32, u32>> &keep) {
if (keep.empty()) {
ClearCache();
return;
}
int kept = 0;
int invalidated = 0;
for (int block_num = 0; block_num < blocks_.GetNumBlocks(); ++block_num) {
const IRBlock *block = blocks_.GetBlock(block_num);
if (!block->IsValid()) {
continue;
}
u32 start, size;
block->GetRange(&start, &size);
start &= 0x3FFFFFFF;
bool inside = false;
for (const auto &[keepStart, keepSize] : keep) {
const u32 maskedStart = keepStart & 0x3FFFFFFF;
if (start >= maskedStart && start + size <= maskedStart + keepSize) {
inside = true;
break;
}
}
if (inside) {
kept++;
} else {
InvalidateBlock(block_num);
invalidated++;
}
}
INFO_LOG(Log::JIT, "IRJit: Kept %d blocks, invalidated %d", kept, invalidated);
}
void IRJit::Compile(u32 em_address) {
_dbg_assert_(compilerEnabled_);
PROFILE_THIS_SCOPE("jitc");
std::vector<IRInst> instructions;
u32 mipsBytes;
const CompileResult result = CompileBlock(em_address, instructions, mipsBytes);
if (result != CompileResult::OK) {
if (result == CompileResult::ARENA_FULL) {
ERROR_LOG(Log::JIT, "IR arena full (%d blocks), clearing cache", blocks_.GetNumBlocks());
irArenaFullClears_++;
} else {
ERROR_LOG(Log::JIT, "Native code space full (%d blocks), clearing cache", blocks_.GetNumBlocks());
codeFullClears_++;
}
ClearCache();
CompileBlock(em_address, instructions, mipsBytes);
}
if (frontend_.CheckRounding(em_address)) {
// Our assumptions are all wrong so it's clean-slate time.
ClearCache();
CompileBlock(em_address, instructions, mipsBytes);
}
}
// WARNING! This can be called from IRInterpret / the JIT, through the function preload stuff!
IRJit::CompileResult IRJit::CompileBlock(u32 em_address, std::vector<IRInst> &instructions, u32 &mipsBytes) {
_dbg_assert_(compilerEnabled_);
frontend_.DoJit(em_address, instructions, mipsBytes);
_dbg_assert_(!instructions.empty());
int block_num = blocks_.AllocateBlock(em_address, mipsBytes, instructions);
if (block_num < 0) {
WARN_LOG(Log::JIT, "Failed to allocate block for %08x (%d instructions)", em_address, (int)instructions.size());
// Caller will handle.
return CompileResult::ARENA_FULL;
}
IRBlock *b = blocks_.GetBlock(block_num);
if (mipsTracer.tracing_enabled) {
// Hash, then only update page stats, don't link yet.
// TODO: Should we always hash? Then we can reuse blocks.
b->UpdateHash();
}
if (!CompileNativeBlock(&blocks_, block_num))
return CompileResult::CODE_FULL;
if (mipsTracer.tracing_enabled) {
mipsTracer.prepare_block(b, blocks_);
}
// Updates stats, also enters the block in the block shadow.
blocks_.FinalizeBlock(block_num);
FinalizeNativeBlock(&blocks_, block_num);
return CompileResult::OK;
}
void IRJit::GetStats(JitStats *stats) const {
stats->numBlocks = blocks_.GetNumBlocks();
stats->numValidBlocks = blocks_.CountValidBlocks();
stats->irArenaUsed = blocks_.GetArenaSize();
stats->irArenaSize = IRBlockCache::MAX_ARENA_SIZE;
stats->irArenaFullClears = irArenaFullClears_;
stats->codeFullClears = codeFullClears_;
stats->invalidations = invalidations_;
stats->invalidatedBlocks = invalidatedBlocks_;
}
void IRJit::RunLoopUntil(u64 globalticks) {
PROFILE_THIS_SCOPE("jit");
if (profiling_)
RunBlocks<true>();
else
RunBlocks<false>();
}
template <bool profile>
void IRJit::RunBlocks() {
// IR Dispatcher
// The guest's rounding mode applies while running blocks, like in the native JITs' dispatchers
// (see ApplyHostRoundingMode).
MIPSState *mips = mips_;
while (true) {
RestoreHostRoundingMode();
CoreTiming::Advance(mips);
if (coreState != 0) {
break;
}
ApplyHostRoundingMode(mips);
#ifdef _DEBUG
compilerEnabled_ = false;
#endif
while (mips->downcount >= 0) {
// The block's offset into the IR arena, or 0 for none, or a replacement hook (handled by
// compiling a block).
const u32 offset = *Memory::GetBlockShadowEntry(mips->pc);
static_assert(Memory::BLOCK_SHADOW_HOOK_NO_JIT == 1, "IR arena reserves offsets 0 and 1");
if (offset > Memory::BLOCK_SHADOW_HOOK_NO_JIT) {
const IRInst *instPtr = blocks_.GetArenaPtr() + offset;
// First op is always, except when using breakpoints, downcount, to save one dispatch inside IRInterpret.
// This branch is very cpu-branch-predictor-friendly so this still beats the dispatch.
if (instPtr->op == IROp::Downcount) {
mips->downcount -= instPtr->constant;
instPtr++;
}
if constexpr (profile) {
IRBlock *block = blocks_.GetBlock(blocks_.GetBlockNumFromIRArenaOffset(offset));
Instant start = Instant::Now();
mips->pc = IRInterpret(mips, instPtr);
block->profileStats_.executions += 1;
block->profileStats_.totalNanos += start.ElapsedNanos();
} else {
// Runs on through the blocks it can, as long as downcount lasts.
mips->pc = IRInterpret(mips, instPtr, blocks_.GetArenaPtr());
}
// Note: this will "jump to zero" on a badly constructed block missing exits.
if (!Memory::IsValid4AlignedAddress(mips->pc)) {
int blockNum = blocks_.GetBlockNumFromIRArenaOffset(offset);
IRBlock *block = blocks_.GetBlockUnchecked(blockNum);
Core_ExecException(mips->pc, block->GetOriginalStart(), ExecExceptionType::JUMP);
break;
}
} else {
RestoreHostRoundingMode();
#ifdef _DEBUG
compilerEnabled_ = true;
#endif
Compile(mips->pc);
#ifdef _DEBUG
compilerEnabled_ = false;
#endif
ApplyHostRoundingMode(mips);
}
}
#ifdef _DEBUG
compilerEnabled_ = true;
#endif
}
RestoreHostRoundingMode();
}
bool IRJit::DescribeCodePtr(const u8 *ptr, std::string &name) {
// Used in native disassembly viewer.
return false;
}
void IRBlockCache::Clear() {
for (int i = 0; i < (int)blocks_.size(); ++i) {
int cookie = compileToNative_ ? blocks_[i].GetNativeOffset() : blocks_[i].GetIRArenaOffset();
blocks_[i].Destroy(cookie);
}
blocks_.clear();
byPage_.clear();
arena_.clear();
arena_.shrink_to_fit();
}
IRBlockCache::IRBlockCache(bool compileToNative) : compileToNative_(compileToNative) {}
int IRBlockCache::CountValidBlocks() const {
int count = 0;
for (const IRBlock &block : blocks_) {
if (block.IsValid()) {
count++;
}
}
return count;
}
int IRBlockCache::AllocateBlock(int emAddr, u32 origSize, const std::vector<IRInst> &insts) {
if (arena_.empty()) {
// Offset 0 would mean "no block" in the block shadow, and 1 a replacement hook.
arena_.push_back(IRInst{ IROp::Bad });
arena_.push_back(IRInst{ IROp::Bad });
}
int offset = (int)arena_.size();
if (offset >= MAX_ARENA_SIZE) {
WARN_LOG(Log::JIT, "Filled JIT arena, restarting");
return -1;
}
// TODO: Use memcpy.
for (size_t i = 0; i < insts.size(); i++) {
arena_.push_back(insts[i]);
}
int newBlockIndex = (int)blocks_.size();
blocks_.push_back(IRBlock(emAddr, origSize, offset, (u32)insts.size()));
return newBlockIndex;
}
int IRBlockCache::GetBlockNumFromIRArenaOffset(int offset) const {
// Block offsets are always in rising order (we don't go back and replace them when invalidated). So we can binary search.
int low = 0;
int high = (int)blocks_.size() - 1;
int found = -1;
while (low <= high) {
int mid = low + (high - low) / 2;
const int blockOffset = blocks_[mid].GetIRArenaOffset();
if (blockOffset == offset) {
found = mid;
break;
}
if (blockOffset < offset) {
low = mid + 1;
} else {
high = mid - 1;
}
}
return found;
#if 1
return found;
#else
// Cross check the result. This is not fast so normally not enabled. Called a lot when profiling.
for (int i = 0; i < (int)blocks_.size(); i++) {
if (blocks_[i].GetIRArenaOffset() == offset) {
_dbg_assert_(i == found);
return i;
}
}
_dbg_assert_(found == -1);
return -1;
#endif
}
std::vector<int> IRBlockCache::FindInvalidatedBlockNumbers(u32 address, u32 lengthInBytes) {
u32 startPage = AddressToPage(address);
u32 endPage = AddressToPage(address + lengthInBytes);
std::vector<int> found;
for (u32 page = startPage; page <= endPage; ++page) {
const auto iter = byPage_.find(page);
if (iter == byPage_.end())
continue;
const std::vector<int> &blocksInPage = iter->second;
for (int i : blocksInPage) {
if (blocks_[i].OverlapsRange(address, lengthInBytes)) {
// We now try to remove these during invalidation.
found.push_back(i);
}
}
}
return found;
}
void IRBlockCache::FinalizeBlock(int blockIndex) {
// TODO: What's different about preload blocks?
IRBlock &block = blocks_[blockIndex];
int cookie = compileToNative_ ? block.GetNativeOffset() : block.GetIRArenaOffset();
block.Finalize(cookie);
u32 startAddr, size;
block.GetRange(&startAddr, &size);
u32 startPage = AddressToPage(startAddr);
u32 endPage = AddressToPage(startAddr + size);
for (u32 page = startPage; page <= endPage; ++page) {
byPage_[page].push_back(blockIndex);
}
}
// Call after Destroy-ing it.
void IRBlockCache::RemoveBlockFromPageLookup(int blockIndex) {
// We need to remove the block from the byPage lookup.
IRBlock &block = blocks_[blockIndex];
u32 startAddr, size;
block.GetRange(&startAddr, &size);
u32 startPage = AddressToPage(startAddr);
u32 endPage = AddressToPage(startAddr + size);
for (u32 page = startPage; page <= endPage; ++page) {
auto iter = std::find(byPage_[page].begin(), byPage_[page].end(), blockIndex);
if (iter != byPage_[page].end()) {
byPage_[page].erase(iter);
} else if (block.IsValid()) {
// If it was previously invalidated, we don't care, hence the above check.
WARN_LOG(Log::JIT, "RemoveBlock: Block at %08x was not found where expected in byPage table.", startAddr);
}
}
// Additionally, we'd like to zap the block in the IR arena.
// However, this breaks if calling sceKernelIcacheClearAll(), since as soon as we return, we'll be executing garbage.
/*
IRInst bad{ IROp::Bad };
for (int off = block.GetIRArenaOffset(); off < (int)(block.GetIRArenaOffset() + block.GetNumIRInstructions()); off++) {
arena_[off] = bad;
}
*/
}
u32 IRBlockCache::AddressToPage(u32 addr) const {
// Use relatively small pages since basic blocks are typically small.
return (addr & 0x3FFFFFFF) >> 10;
}
int IRBlockCache::FindPreloadBlock(u32 em_address) {
u32 page = AddressToPage(em_address);
auto iter = byPage_.find(page);
if (iter == byPage_.end())
return -1;
const std::vector<int> &blocksInPage = iter->second;
for (int i : blocksInPage) {
if (blocks_[i].GetOriginalStart() == em_address) {
if (blocks_[i].HashMatches()) {
return i;
}
}
}
return -1;
}
int IRBlockCache::FindByCookie(int cookie) {
if (blocks_.empty())
return -1;
// TODO: Maybe a flag to determine native offset mode?
if (!compileToNative_) {
return GetBlockNumFromIRArenaOffset(cookie);
}
// TODO: This could also use a binary search.
for (int i = 0; i < GetNumBlocks(); ++i) {
int offset = blocks_[i].GetNativeOffset();
if (offset == cookie)
return i;
}
return -1;
}
JitBlockDebugInfo IRBlockCache::GetBlockDebugInfo(int blockNum) const {
const IRBlock &ir = blocks_[blockNum];
JitBlockDebugInfo debugInfo{};
uint32_t start, size;
ir.GetRange(&start, &size);
debugInfo.originalAddress = start; // TODO
if (!Memory::IsValid4AlignedAddress(start)) {
return debugInfo;
}
debugInfo.origDisasm.reserve(((start + size) - start) / 4);
for (u32 addr = start; addr < start + size; addr += 4) {
char temp[256];
MIPSDisAsm(Replacement_GetDisplayOp(addr), addr, temp, sizeof(temp), true);
std::string mipsDis = temp;
debugInfo.origDisasm.push_back(mipsDis);
}
debugInfo.irDisasm.reserve(ir.GetNumIRInstructions());
const IRInst *instructions = GetBlockInstructionPtr(ir);
for (int i = 0; i < ir.GetNumIRInstructions(); i++) {
IRInst inst = instructions[i];
char buffer[256];
DisassembleIR(buffer, sizeof(buffer), inst);
debugInfo.irDisasm.push_back(buffer);
}
return debugInfo;
}
void IRBlockCache::ComputeStats(BlockCacheStats &bcStats) const {
double totalBloat = 0.0;
double maxBloat = 0.0;
double minBloat = 1000000000.0;
for (const auto &b : blocks_) {
double codeSize = (double)b.GetNumIRInstructions() * 4; // We count bloat in instructions, not bytes. sizeof(IRInst);
if (codeSize == 0)
continue;
u32 origAddr, mipsBytes;
b.GetRange(&origAddr, &mipsBytes);
double origSize = (double)mipsBytes;
double bloat = codeSize / origSize;
if (bloat < minBloat) {
minBloat = bloat;
bcStats.minBloatBlock = origAddr;
}
if (bloat > maxBloat) {
maxBloat = bloat;
bcStats.maxBloatBlock = origAddr;
}
totalBloat += bloat;
}
bcStats.numBlocks = (int)blocks_.size();
bcStats.minBloat = minBloat;
bcStats.maxBloat = maxBloat;
bcStats.avgBloat = totalBloat / (double)blocks_.size();
}
int IRBlockCache::GetBlockNumberFromStartAddress(u32 em_address) const {
u32 page = AddressToPage(em_address);
const auto iter = byPage_.find(page);
if (iter == byPage_.end())
return -1;
const std::vector<int> &blocksInPage = iter->second;
int best = -1;
for (int i : blocksInPage) {
if (blocks_[i].GetOriginalStart() == em_address) {
best = i;
if (blocks_[i].IsValid()) {
return i;
}
}
}
return best;
}
void IRBlock::Finalize(int cookie) {
// Check it wasn't invalidated, in case this is after preload.
// TODO: Allow reusing blocks when the code matches hash_ again, instead.
if (origAddr_ && Memory::IsValid4AlignedAddress(origAddr_)) {
origFirstOpcode_ = Memory::ReadUnchecked_Instruction(origAddr_);
_dbg_assert_(cookie != 0);
Memory::WriteBlockShadow(origAddr_, cookie);
} else {
WARN_LOG(Log::JIT, "Finalizing invalid block (cookie: %d)", cookie);
}
}
void IRBlock::Destroy(int cookie) {
if (origAddr_ && Memory::IsValid4AlignedAddress(origAddr_)) {
// A block at a mirror may have taken over the entry, leave that alone.
Memory::ClearBlockShadow(origAddr_, cookie);
// TODO: Also wipe the block in the IR opcode arena.
// Let's mark this invalid so we don't try to clear it again.
origAddr_ = 0;
}
}
u64 IRBlock::CalculateHash() const {
if (origAddr_ && Memory::IsValidRange(origAddr_, origSize_)) {
return XXH3_64bits(Memory::GetPointerUnchecked(origAddr_), origSize_);
}
return 0;
}
bool IRBlock::OverlapsRange(u32 addr, u32 size) const {
addr &= 0x3FFFFFFF;
u32 origAddr = origAddr_ & 0x3FFFFFFF;
return addr + size > origAddr && addr < origAddr + origSize_;
}
} // namespace MIPSComp