/// <summary>
/// 获取寄存器，isResult为true，则说明需要返回的是存放结果的寄存器
/// </summary>
/// <param name="f">四元式</param>
/// <param name="varTable">变量表</param>
/// <param name="isResult">指定获取的寄存器是否是用来存放计算结果</param>
/// <param name="cmdList">汇编指令列表</param>
/// <returns>寄存器名</returns>
private string getReg(FourExp f, VarTable varTable, bool isResult, List<AssemblerIns> cmdList)
{
//返回B或者C所在的寄存器
if (isResult)
{
if ((f.Arg1 != "") && (varTable.GetAddrInfo(f.Arg1) != ""))
{
string regB = varTable.GetAddrInfo(f.Arg1);
if ((varTable.GetPeekActInfo(f.Arg1) == false) || f.Arg1 == f.Result || regUseTable.GetContent(regB).Count == 1)
{
return regB;
}
}
if ((f.Arg2 != "") && (varTable.GetAddrInfo(f.Arg2) != ""))
{
string regC = varTable.GetAddrInfo(f.Arg1);
if ((varTable.GetPeekActInfo(f.Arg2) == false) || f.Arg2 == f.Result || regUseTable.GetContent(regC).Count == 1)
{
return regC;
}
}
}
//返回未占用寄存器
foreach (string regName in registers)
{
if (regUseTable.GetContent(regName) == null)
{
return regName;
}
}
//随机返回一个已占用的寄存器
Random r = new Random();
while (true)
{
int i = r.Next(registers.Length);
string reg = registers[i];
List<string> varList = new List<string>() { f.Arg1, f.Arg2, f.Result };
if (!regUseTable.Contains(reg, varList))
{
//调整变量表和寄存器表中的相关域
doAdjust(reg, varTable, cmdList);
return reg;
}
}
}
/// <summary>
/// 将四元式翻译为汇编指令
/// </summary>
/// <param name="f">四元式</param>
/// <param name="varTable">变量表</param>
/// <param name="cmdList">汇编指令列表</param>
private void convert(FourExp f, VarTable varTable, List<AssemblerIns> cmdList)
{
#region Label FourExp
if (f.Op == FourExpOperation.label)
{
cmdList.Add(AssemblerFac.GenLABEL(f.LabelName));
}
#endregion
#region Jump Operation
if (f.Op >= FourExpOperation.jmp && f.Op <= FourExpOperation.jle)
{
string operation = "";
switch (f.Op)
{
case FourExpOperation.jmp:
operation = Mnemonic.J.ToString();
cmdList.Add(AssemblerFac.GenJ(f.TargetLabel));
break;
case FourExpOperation.je:
operation = Mnemonic.BEQ.ToString();
doJump(f, operation, varTable, cmdList);
break;
case FourExpOperation.jne:
operation = Mnemonic.BNE.ToString();
doJump(f, operation, varTable, cmdList);
break;
case FourExpOperation.jg:
operation = Mnemonic.BGTZ.ToString();
doJump(f, operation, varTable, cmdList);
break;
case FourExpOperation.jge:
operation = Mnemonic.BGEZ.ToString();
doJump(f, operation, varTable, cmdList);
break;
case FourExpOperation.jl:
operation = Mnemonic.BLTZ.ToString();
doJump(f, operation, varTable, cmdList);
break;
case FourExpOperation.jle:
operation = Mnemonic.BLEZ.ToString();
doJump(f, operation, varTable, cmdList);
break;
default:
//错误处理
break;
}
}
#endregion
#region Move Operation
else if (f.Op == FourExpOperation.mov)
{
string regB = "";
if (isNumber(f.Arg1))
{
regB = getReg(f, varTable, false, cmdList);
int value = Convert.ToInt32(f.Arg1);
if (value <= 32767 && value >= -32768)
{
cmdList.Add(AssemblerFac.GenLUI(regB, value.ToString()));
cmdList.Add(AssemblerFac.GenSRL(regB, regB, 16 + ""));
}
else
{
short high = Convert.ToInt16(value >> 16);
cmdList.Add(AssemblerFac.GenLUI(regB, high + ""));
short low = Convert.ToInt16(value & 0xffff);
cmdList.Add(AssemblerFac.GenORI(regB, regB, low + ""));
}
}
else
{
if (varTable.GetAddrInfo(f.Arg1) == "")
{
regB = getReg(f, varTable, false, cmdList);
cmdList.Add(AssemblerFac.GenLW(regB, varTable.GetAddr(f.Arg1).ToString(), "$ZERO"));
regUseTable.GetContent(regB).Add(f.Arg1);
varTable.SetAddrInfo(f.Arg1, regB);
}
else
{
regB = varTable.GetAddrInfo(f.Arg1);
}
}
regUseTable.GetContent(regB).Add(f.Result);
varTable.SetAddrInfo(f.Result, regB);
if(varTable.Contains(f.Arg1) && varTable.GetPeekActInfo(f.Arg1) == false)
{
cmdList.Add(AssemblerFac.GenSW(regB, varTable.GetAddr(f.Arg1).ToString(), "$ZERO"));
varTable.SetAddrInfo(f.Arg1, "");
regUseTable.GetContent(regB).Remove(f.Arg1);
}
if (varTable.Contains(f.Result) && varTable.GetPeekActInfo(f.Result) == false)
{
cmdList.Add(AssemblerFac.GenSW(regB, varTable.GetAddr(f.Result).ToString(), "$ZERO"));
varTable.SetAddrInfo(f.Result, "");
regUseTable.GetContent(regB).Remove(f.Result);
}
}
#endregion
#region Arithmetical or Logical Operation
else if (f.Op <= FourExpOperation.or)//数学或逻辑运算
{
//获取第一个参数的寄存器
string regA, regB, regC;
if (isNumber(f.Arg1))
{
regB = getReg(f, varTable, false, cmdList);
int value = Convert.ToInt32(f.Arg1);
if (value <= 32767 && value >= -32768)
{
cmdList.Add(AssemblerFac.GenLUI(regB, value.ToString()));
cmdList.Add(AssemblerFac.GenSRL(regB, regB, 16 + ""));
}
else
{
short high = Convert.ToInt16(value >> 16);
cmdList.Add(AssemblerFac.GenLUI(regB, high + ""));
short low = Convert.ToInt16(value & 0xffff);
cmdList.Add(AssemblerFac.GenORI(regB, regB, low + ""));
}
}
else
{
if (varTable.GetAddrInfo(f.Arg1) == "")
{
regB = getReg(f, varTable, false, cmdList);
varTable.SetAddrInfo(f.Arg1, regB);
regUseTable.Add(regB, f.Arg1);
cmdList.Add(AssemblerFac.GenLW(regB, varTable.GetAddr(f.Arg1).ToString(), "$ZERO"));
}
else
{
regB = varTable.GetAddrInfo(f.Arg1);
}
}
//获取第二个参数的寄存器
if (isNumber(f.Arg1))
{
regC = getReg(f, varTable, false, cmdList);
int value = Convert.ToInt32(f.Arg2);
if (value <= 32767 && value >= -32768)
{
cmdList.Add(AssemblerFac.GenLUI(regC, value.ToString()));
cmdList.Add(AssemblerFac.GenSRL(regC, regC, 16 + ""));
}
else
{
short high = Convert.ToInt16(value >> 16);
cmdList.Add(AssemblerFac.GenLUI(regC, high + ""));
short low = Convert.ToInt16(value & 0xffff);
cmdList.Add(AssemblerFac.GenORI(regC, regC, low + ""));
}
}
else
{
if (varTable.GetAddrInfo(f.Arg2) == "")
{
regC = getReg(f, varTable, false, cmdList);
varTable.SetAddrInfo(f.Arg2, regC);
regUseTable.Add(regC, f.Arg2);
cmdList.Add(AssemblerFac.GenLW(regC, varTable.GetAddr(f.Arg2).ToString(), "$ZERO"));
}
else
{
regC = varTable.GetAddrInfo(f.Arg2);
}
}
//获取计算结果的寄存器
regA = getReg(f, varTable, true, cmdList);
varTable.SetAddrInfo(f.Result, regA);
regUseTable.Add(regA, f.Result);
if (regA == regB)
{
foreach (string var in regUseTable.GetContent(regB))
{
cmdList.Add(AssemblerFac.GenSW(regB, varTable.GetAddr(var).ToString(), "$ZERO"));
varTable.SetAddrInfo(var, "");
regUseTable.GetContent(regB).Remove(var);
}
}
if (regA == regC)
{
foreach (string var in regUseTable.GetContent(regC))
{
cmdList.Add(AssemblerFac.GenSW(regC, varTable.GetAddr(var).ToString(), "$ZERO"));
varTable.SetAddrInfo(var, "");
regUseTable.GetContent(regC).Remove(var);
}
}
string operation = "";
switch (f.Op)
{
case FourExpOperation.add:
operation = Mnemonic.ADD.ToString();
break;
case FourExpOperation.sub:
operation = Mnemonic.SUB.ToString();
break;
//case FourExpOperation.mul:
// break;
//case FourExpOperation.div:
// break;
case FourExpOperation.and:
operation = Mnemonic.AND.ToString();
break;
case FourExpOperation.or:
operation = Mnemonic.OR.ToString();
break;
case FourExpOperation.xor:
operation = Mnemonic.XOR.ToString();
break;
case FourExpOperation.nor:
operation = Mnemonic.NOR.ToString();
break;
default:
//错误处理
break;
}
cmdList.Add(AssemblerFac.GenMathOrLog(operation, regA, regB, regC));
if (varTable.Contains(f.Arg1) && (varTable.GetAddrInfo(f.Arg1) != null) && (varTable.GetPeekActInfo(f.Arg1) == false))
{
cmdList.Add(AssemblerFac.GenSW(regB, varTable.GetAddr(f.Arg1).ToString(), "$ZERO"));
varTable.SetAddrInfo(f.Arg1, "");
regUseTable.GetContent(regB).Remove(f.Arg1);
}
if (varTable.Contains(f.Arg2) && (varTable.GetAddrInfo(f.Arg2) != null) && (varTable.GetPeekActInfo(f.Arg2) == false))
{
cmdList.Add(AssemblerFac.GenSW(regC, varTable.GetAddr(f.Arg2).ToString(), "$ZERO"));
varTable.SetAddrInfo(f.Arg2, "");
regUseTable.GetContent(regC).Remove(f.Arg2);
}
if (varTable.Contains(f.Result) && varTable.GetPeekActInfo(f.Result) == false)
{
cmdList.Add(AssemblerFac.GenSW(regA, varTable.GetAddr(f.Result).ToString(), "$ZERO"));
varTable.SetAddrInfo(f.Result, "");
regUseTable.GetContent(regA).Remove(f.Result);
}
}
#endregion
#region Not or Neg Operation
else if (f.Op == FourExpOperation.neg)
{
string regB;
if (isNumber(f.Arg1))
{
regB = getReg(f, varTable, false, cmdList);
int value = Convert.ToInt32(f.Arg1);
if (value <= 32767 && value >= -32768)
{
cmdList.Add(AssemblerFac.GenLUI(regB, value.ToString()));
cmdList.Add(AssemblerFac.GenSRL(regB, regB, 16 + ""));
}
else
{
short high = Convert.ToInt16(value >> 16);
cmdList.Add(AssemblerFac.GenLUI(regB, high + ""));
short low = Convert.ToInt16(value & 0xffff);
cmdList.Add(AssemblerFac.GenORI(regB, regB, low + ""));
}
}
else
{
regB = varTable.GetAddrInfo(f.Arg1);
if (regB == "")
{
regB = getReg(f, varTable, false, cmdList);
cmdList.Add(AssemblerFac.GenLW(regB, varTable.GetAddr(f.Arg1).ToString(), "$ZERO"));
varTable.SetAddrInfo(f.Arg1, regB);
regUseTable.GetContent(regB).Add(f.Arg1);
}
}
string regA = varTable.GetAddrInfo(f.Result);
if (regA == "")
{
regA = getReg(f, varTable, true, cmdList);
varTable.SetAddrInfo(f.Result, regA);
regUseTable.GetContent(regA).Add(f.Result);
}
cmdList.Add(AssemblerFac.GenSUB(regA, "$ZERO", regB));
if (varTable.Contains(f.Arg1) && varTable.GetPeekActInfo(f.Arg1) == false)
{
cmdList.Add(AssemblerFac.GenSW(regB, varTable.GetAddr(f.Arg1).ToString(), "$ZERO"));
varTable.SetAddrInfo(f.Arg1, "");
regUseTable.GetContent(regB).Remove(f.Arg1);
}
if (varTable.Contains(f.Arg1) && varTable.GetPeekActInfo(f.Result) == false)
{
cmdList.Add(AssemblerFac.GenSW(regA, varTable.GetAddr(f.Result).ToString(), "$ZERO"));
varTable.SetAddrInfo(f.Result, "");
regUseTable.GetContent(regA).Remove(f.Result);
}
}
else if (f.Op == FourExpOperation.not)
{
string regB;
if (isNumber(f.Arg1))
{
regB = getReg(f, varTable, false, cmdList);
int value = Convert.ToInt32(f.Arg1);
if (value <= 32767 && value >= -32768)
{
cmdList.Add(AssemblerFac.GenLUI(regB, value.ToString()));
cmdList.Add(AssemblerFac.GenSRL(regB, regB, 16 + ""));
}
else
{
short high = Convert.ToInt16(value >> 16);
cmdList.Add(AssemblerFac.GenLUI(regB, high + ""));
short low = Convert.ToInt16(value & 0xffff);
cmdList.Add(AssemblerFac.GenORI(regB, regB, low + ""));
}
}
else
{
regB = varTable.GetAddrInfo(f.Arg1);
if (regB == "")
{
regB = getReg(f, varTable, false, cmdList);
cmdList.Add(AssemblerFac.GenLW(regB, varTable.GetAddr(f.Arg1).ToString(), "$ZERO"));
varTable.SetAddrInfo(f.Arg1, regB);
regUseTable.GetContent(regB).Add(f.Arg1);
}
}
string regA = varTable.GetAddrInfo(f.Result);
if (regA == "")
{
regA = getReg(f, varTable, true, cmdList);
varTable.SetAddrInfo(f.Result, regA);
regUseTable.GetContent(regA).Add(f.Result);
}
cmdList.Add(AssemblerFac.GenXORI(regA, regB, Convert.ToString(1)));//a = NOT b => a = b xor 1
if (varTable.Contains(f.Arg1) && varTable.GetPeekActInfo(f.Arg1) == false)
{
cmdList.Add(AssemblerFac.GenSW(regB, varTable.GetAddr(f.Arg1).ToString(), "$ZERO"));
varTable.SetAddrInfo(f.Arg1, "");
regUseTable.GetContent(regB).Remove(f.Arg1);
}
if (varTable.Contains(f.Result) && varTable.GetPeekActInfo(f.Result) == false)
{
cmdList.Add(AssemblerFac.GenSW(regA, varTable.GetAddr(f.Result).ToString(), "$ZERO"));
varTable.SetAddrInfo(f.Result, "");
regUseTable.GetContent(regA).Remove(f.Result);
}
}
#endregion
#region Rightshift or Leftshift
else if (f.Op == FourExpOperation.leftshift || f.Op == FourExpOperation.rightshift)
{
}
#endregion
else
{
//错误处理
}
}
/// <summary>
/// 翻译跳转指令
/// </summary>
/// <param name="f">四元式</param>
/// <param name="operation">汇编指令的操作助记符</param>
/// <param name="varTable">变量表</param>
/// <param name="cmdList">汇编指令列表</param>
private void doJump(FourExp f, string operation, VarTable varTable, List<AssemblerIns> cmdList)
{
string reg1 = "", reg2 = "";
reg1 = varTable.GetAddrInfo(f.Arg1);
reg2 = varTable.GetAddrInfo(f.Arg2);
if (reg1 == "")
{
reg1 = getReg(f, varTable, false, cmdList);
cmdList.Add(AssemblerFac.GenLW(reg1, varTable.GetAddr(f.Arg1).ToString(), "$ZERO"));
regUseTable.GetContent(reg1).Add(f.Arg1);
varTable.SetAddrInfo(f.Arg1, reg1);
}
if (reg2 == "")
{
reg2 = getReg(f, varTable, false, cmdList);
cmdList.Add(AssemblerFac.GenLW(reg2, varTable.GetAddr(f.Arg2).ToString(), "$ZERO"));
regUseTable.GetContent(reg2).Add(f.Arg2);
varTable.SetAddrInfo(f.Arg2, reg2);
}
cmdList.Add(AssemblerFac.GenSLT("$T0", reg1, reg2));
cmdList.Add(AssemblerFac.GenJUMP(operation, "$T0", f.TargetLabel.ToString()));
adjustAfterJump(f, reg1, reg2, varTable, cmdList);
}