diff --git a/src/Backend.cpp b/src/Backend.cpp
deleted file mode 100644
index e1435ab..0000000
--- a/src/Backend.cpp
+++ /dev/null
@@ -1,295 +0,0 @@
-#include "Backend.h"
-using namespace sysy;
-
-namespace sysy {
-
-using RegId = RegManager::RegId;
-
-string CodeGen::code_gen() {
-  string code;
-  code += module_gen(module);
-  return code;
-}
-
-string CodeGen::module_gen(Module *module) {
-  string code;
-  string dataCode;
-  string textCode;
-  // clear last module's label record
-  clearModuleRecord(module);
-  // generate asmcode for all global values
-  dataCode += globaldata_gen();
-
-  code += space + ".arch armv7ve " + eol;
-  code += space + ".text " + eol;
-  auto functions = module->getFunctions();
-
-  for (auto iter = functions->begin(); iter != functions->end(); ++iter) {
-    string name = iter->first;
-    Function *func = iter->second;
-    auto bblist = func->getBasicBlocks();
-    if (bblist.empty())
-      continue;
-    // generate asmcode for each function
-    textCode += function_gen(func) + eol;
-  }
-  code += (dataCode + textCode + eol);
-  return code;
-}
-
-string CodeGen::functionHead_gen(Function *func) {
-  string code;
-  code += space + ".globl " + func->getName() + eol;
-  code += space + ".p2align " + std::to_string(int_p2align) + eol;
-  code += space + ".type " + func->getName() + ", %function" + eol;
-  code += func->getName() + ":" + eol;
-  return code;
-}
-/**
- * stack structure:
- *
- * last function stack
- * --------------------------   <-- fp  point
- * callee-saved regs (include fp, sp, lr)
- * --------------------------
- * local variables and subfunc's return value (ir inst)
- * --------------------------
- * arg0,arg1,arg2,arg3 (as tempory variable)
- * --------------------------
- * caller-saved regs
- * --------------------------
- * arg_x ~ arg_4
- * --------------------------    <-- sp point
- * next function stack
- *
- */
-/**
- * prologue :
- *          preserve callee-saved registers (lr, fp and other callee-saved regs)
- *          set new fp
- *          alloc stack space for local var/ args / return value.
- *          store args to stack
- * */
-string CodeGen::prologueCode_gen(Function *func) {
-  string code;
-  /**
-   *code in here
-   */
-  return code;
-}
-
-/* epilogue :
- *          free stack space
- *          restore sp
- *          restore used callee-saved register(lr, fp and other callee-saved
- * regs) bx lr
- */
-string CodeGen::epilogueCode_gen(Function *func) {
-  string code;
-  /**
-   *code in here
-   */
-  return code;
-}
-
-string CodeGen::function_gen(Function *func) {
-  curFunc = func;
-  clearFunctionRecord(func);
-  string bbCode;
-  auto bbs = func->getBasicBlocks();
-  for (auto iter = bbs.begin(); iter != bbs.end(); ++iter) {
-    auto bb = iter->get();
-    bbCode += basicBlock_gen(bb);
-  }
-  string code;
-  string funcHead = functionHead_gen(func);
-  string prologueCode = prologueCode_gen(func);
-  string epilogueCode = epilogueCode_gen(func);
-  string literalPoolsCode = literalPoolsCode_gen(func);
-  //
-  code = funcHead + prologueCode + bbCode + epilogueCode + literalPoolsCode;
-  return code;
-}
-
-string CodeGen::basicBlock_gen(BasicBlock *bb) {
-  curBB = bb;
-  string bbLabel = getBBLabel(bb);
-  string code;
-  code += bbLabel + ":" + eol;
-  for (auto &instr : bb->getInstructions()) {
-    auto instrType = instr->getKind();
-    code += instruction_gen(instr.get());
-  }
-  return code;
-}
-/**
- * RegId : binaryInst_gen returns RegId as its destination operand
- * code  : asmcode generated by binaryInst_gen
- */
-pair<RegId, string> CodeGen::binaryInst_gen(BinaryInst *bInst, RegId dstRegId) {
-  string code;
-  /**
-   *code in here
-   */
-  return {dstRegId, code};
-}
-
-pair<RegId, string> CodeGen::unaryInst_gen(UnaryInst *uInst, RegId dstRegId) {
-  string code;
-  /**
-   *code in here
-   */
-  return {dstRegId, code};
-}
-pair<RegId, string> CodeGen::allocaInst_gen(AllocaInst *aInst,
-                                            RegManager::RegId dstRegId) {
-  string code;
-  /**
-   *code in here
-   */
-  return {dstRegId, code};
-}
-
-string CodeGen::storeInst_gen(StoreInst *stInst) {
-  string code;
-  /**
-   *code in here
-   */
-  return code;
-}
-pair<RegId, string> CodeGen::loadInst_gen(LoadInst *ldInst, RegId dstRegId) {
-  string code;
-  /**
-   *code in here
-   */
-  return {dstRegId, code};
-}
-string CodeGen::returnInst_gen(ReturnInst *retInst) {
-  string code;
-  /**
-   *code in here
-   */
-  return code;
-}
-string CodeGen::uncondBrInst_gen(UncondBrInst *ubInst) {
-  string code;
-  /**
-   *code in here
-   */
-  return code;
-}
-string CodeGen::condBrInst_gen(CondBrInst *cbInst) {
-  string code;
-  /**
-   *code in here
-   */
-  return code;
-}
-pair<RegId, string> CodeGen::callInst_gen(CallInst *callInst, RegId dstRegId) {
-  string code;
-  /**
-   *code in here
-   */
-  return {dstRegId, code};
-}
-
-string CodeGen::instruction_gen(Instruction *instr) {
-  string code;
-  string unkName = instr->getName();
-  RegManager::RegId dstRegId = RegManager::RNONE;
-  auto instrType = instr->getKind();
-  pair<RegId, string> tmp;
-  switch (instrType) {
-  // binary inst
-  case Instruction::kAdd:
-  case Instruction::kMul:
-  case Instruction::kSub: {
-    BinaryInst *bInst = dynamic_cast<BinaryInst *>(instr);
-    // registers are used only for instruction operation, consider use which
-    // register (any one that is free for use)
-    tmp = binaryInst_gen(bInst, RegManager::RANY);
-    code += tmp.second;
-    dstRegId = tmp.first;
-    break;
-  }
-  case Instruction::kLoad: {
-    LoadInst *ldInst = dynamic_cast<LoadInst *>(instr);
-    tmp = loadInst_gen(ldInst, RegManager::RANY);
-    code += M_emitComment("load inst");
-    code += tmp.second;
-    dstRegId = tmp.first;
-    break;
-  }
-  case Instruction::kStore: {
-    StoreInst *stInst = dynamic_cast<StoreInst *>(instr);
-    code += M_emitComment("store inst");
-    code += storeInst_gen(stInst);
-    return code;
-    break;
-  }
-  case Instruction::kAlloca: {
-    AllocaInst *aInst = dynamic_cast<AllocaInst *>(instr);
-    tmp = allocaInst_gen(aInst, RegManager::RANY);
-    code += M_emitComment("alloca inst");
-    code += tmp.second;
-    dstRegId = tmp.first;
-    break;
-  }
-  case Instruction::kReturn: {
-    ReturnInst *retInst = dynamic_cast<ReturnInst *>(instr);
-    code += M_emitComment("return inst");
-    code += returnInst_gen(retInst);
-    return code;
-    break;
-  }
-  case Instruction::kCall: {
-    CallInst *cInst = dynamic_cast<CallInst *>(instr);
-    auto tmp = callInst_gen(cInst, RegManager::RANY);
-    code += tmp.second;
-    dstRegId = tmp.first;
-    if (dstRegId == RegManager::R0)
-      return code;
-    break;
-  }
-  case Instruction::kBr: {
-    UncondBrInst *ubInst = dynamic_cast<UncondBrInst *>(instr);
-    code += uncondBrInst_gen(ubInst);
-    return code;
-    break;
-  }
-  case Instruction::kCondBr: {
-    CondBrInst *cbInst = dynamic_cast<CondBrInst *>(instr);
-    code += condBrInst_gen(cbInst);
-    return code;
-    break;
-  }
-  default: {
-    code +=
-        "ERROR CODE : instruction " + unkName + " is not implementation" + eol;
-    break;
-  }
-  }
-  if (!instr->getType()->isVoid()) {
-    code += storeRegToStack_gen(dstRegId, instr);
-    // regm.freeReg(dstRegId);//TODO : code in here.
-  }
-  return code;
-}
-//
-string CodeGen::globaldata_gen() {
-  string asmCode;
-  /**
-   *code in here
-   */
-  return asmCode;
-}
-
-string CodeGen::literalPoolsCode_gen(Function *func) {
-  string code;
-  /**
-   *code in here
-   */
-  return code;
-}
-
-} // namespace sysy
diff --git a/src/include/Backend.h b/src/include/Backend.h
deleted file mode 100644
index 9acb6e6..0000000
--- a/src/include/Backend.h
+++ /dev/null
@@ -1,217 +0,0 @@
-#pragma once
-/**
- * 后端设计需要注意的点
- *
- * label分配   :
- * 全局变量的label,常量的label,basicblock的label,函数入口label,函数出口label
- * 全局数据处理
- * 常量处理
- * 临时变量的处理(包括函数参数也是临时变量)
- * 函数参数的处理
- * 块参数的处理  (如果SSA问题通过块传参解决则需要处理块参数)
- * 函数栈空间结构的设计
- * 块的遍历问题
- * arm32的过程调用约定
- *
- * 后端测试需要注意的点
- *
- * 如何汇编与链接.
- * qemu以及树莓派如何运行.
- */
-#include <algorithm>
-#include <set>
-#include <string>
-#include <vector>
-#include "IR.h"
-
-using std::find;
-using std::map;
-using std::pair;
-using std::set;
-using std::string;
-using std::to_string;
-using std::vector;
-
-#define Macro_ERROR_MSG(...)                                                   \
-  do {                                                                         \
-    fprintf(stderr, "ERROR in line-%d of %s: ", __LINE__, __FILE__);           \
-    fprintf(stderr, __VA_ARGS__);                                              \
-    fprintf(stderr, "\n");                                                     \
-    fflush(stderr);                                                            \
-    exit(1);                                                                   \
-  } while (0);
-
-#define M_emitInst(STR) (space + STR + eol)
-#define M_emitComment(STR) (space + "//" + STR + eol)
-#define M_emitLabel(STR) (STR + ":" + eol)
-
-// #define REG_EXP
-
-static const string space = string(4, ' ');
-static const string eol = "\n";
-// only for armv7
-static const int int_align = 4;
-static const int int_size = 4;
-static const int int_p2align = 2;
-static const int reg_size = 4;
-
-// default arm32 max imm
-//
-static const uint32_t maxMovImm = 0xFFF;
-static const string stackIndexReg = "fp";
-
-static uint16_t getWordHigh(uint32_t cval) { return (cval >> 16) & 0xFFFF; }
-static uint16_t getWordLow(uint32_t cval) { return cval & 0xFFFF; }
-//
-static string emitInst_1srcR_noDstR(string name, string srcReg) {
-  return space + name + " " + srcReg + eol;
-}
-static string emitInst_2srcR_1dstR(string name, string srcReg0, string srcReg1,
-                                   string dstReg) {
-  return space + name + " " + dstReg + ", " + srcReg0 + ", " + srcReg1 + eol;
-}
-
-namespace sysy {
-//
-class RegManager {
-public:
-  //{0,1,2,3,4,5,6,7,8,9,10};
-  enum RegId : unsigned {
-    R0 = 0,
-    R1 = 1,
-    R2 = 2,
-    R3 = 3,
-    R4 = 4,
-    R5 = 5,
-    R6 = 6,
-    R7 = 7,
-    R8 = 8,
-    R9 = 9,
-    R10 = 10,
-    RNONE = 1024,
-    RANY = 2048,
-  };
-  static string toString(RegId reg) {
-    if (reg == RNONE)
-      return "RNONE";
-    if (reg == RANY)
-      return "RANY";
-    return "r" + to_string(reg);
-  }
-};
-
-class Operand {
-public:
-  using RegId = RegManager::RegId;
-  enum Kind {
-    kReg,
-    kImm,
-  };
-  Kind kind;
-  union {
-    uint32_t imm;
-    RegId regId;
-  };
-  Operand(){};
-  Operand(uint32_t imm) : kind(kImm), imm(imm) {}
-  Operand(RegId regId) : kind(kReg), regId(regId) {}
-  bool isImm(void) { return kind == kImm; }
-  bool isReg(void) { return kind == kReg; }
-  uint32_t getImm(void) {
-    assert(kind == kImm);
-    return imm;
-  }
-  RegId getRegId(void) {
-    assert(kind == kReg);
-    return regId;
-  }
-  string toString(void) {
-    if (kind == kImm)
-      return "#" + to_string(imm);
-    else
-      return RegManager::toString(regId);
-  }
-};
-
-class CodeGen {
-public:
-  using RegId = RegManager::RegId;
-
-private:
-  sysy::Module *module;
-  Function *curFunc;
-  BasicBlock *curBB;
-  //
-  RegManager regm;
-  // globalValue
-  bool loadGlobalValByMOVWT = true;
-  // basicBlock
-  vector<BasicBlock *> linear_bb;
-  int bb_no = 0;
-  // function params, return value and localVar
-  map<Argument *, int> paramsStOffset;
-  map<Instruction *, int> localVarStOffset;
-  int retValueStOffset = 0;
-  size_t stOffsetAcc = 0;
-  // label manager
-  map<BasicBlock *, string> bb_labels;
-  uint64_t label_no = 0;
-
-public:
-  CodeGen(Module *module) : module(module) {}
-  // code_gen function list
-  string code_gen();
-  string module_gen(Module *module);
-  string function_gen(Function *func);
-  string basicBlock_gen(BasicBlock *bb);
-  string instruction_gen(Instruction *instr);
-  string globaldata_gen();
-  string prologueCode_gen(Function *func);
-  string epilogueCode_gen(Function *func);
-  string literalPoolsCode_gen(Function *func);
-  string functionHead_gen(Function *func);
-  // Module
-  void clearModuleRecord(Module *module) { label_no = 0; }
-  // instruction gen function list
-  //<dstReg, code>
-  pair<RegId, string> loadInst_gen(LoadInst *ldInst, RegId dstRegId);
-  string storeInst_gen(StoreInst *stInst);
-  pair<RegId, string> allocaInst_gen(AllocaInst *aInst, RegId dstRegId);
-  string returnInst_gen(ReturnInst *retInst);
-  pair<RegId, string> callInst_gen(CallInst *retInst, RegId dstRegId);
-  pair<RegId, string> binaryInst_gen(BinaryInst *bInst, RegId dstRegId);
-  pair<RegId, string> unaryInst_gen(UnaryInst *bInst, RegId dstRegId);
-  string uncondBrInst_gen(UncondBrInst *ubInst);
-  string condBrInst_gen(CondBrInst *ubInst);
-
-  //
-  string storeRegToStack_gen(RegId regId, Instruction *inst) {
-    string code;
-    /**
-     *code in here
-     */
-    return code;
-  }
-  // function
-  void clearFunctionRecord(Function *func) {
-    localVarStOffset.clear();
-    paramsStOffset.clear();
-    retValueStOffset = 0;
-    bb_labels.clear();
-    //
-    stOffsetAcc = 0;
-  }
-  string getBBLabel(BasicBlock *bb) {
-    auto t = bb_labels.find(bb);
-    string label;
-    if (t == bb_labels.end()) {
-      label = ".LBB_" + to_string(label_no++);
-      bb_labels.emplace(bb, label);
-    } else {
-      label = t->second;
-    }
-    return label;
-  }
-};
-
-} // namespace sysy
\ No newline at end of file