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Mips汇编器简易实现：基于C#开发的Mips汇编语言解析器与代码生成器
作为一名计算机专业的大二学生，我进行了一个有趣的项目——实现一个简易的Mips汇编器。这个项目不仅让我对汇编语言有了更深入的理解，还锻炼了我对软件开发的能力。以下将详细介绍我的实现过程与成果。
Mips（Multiply-Add-shift-Program)汇编器是一种经典的单指令流控制器，广泛应用于嵌入式系统和硬件开发。由于本项目不支持外部文件引入，仅支持数据段（.data）和代码段（.text），因此我们需要直接处理这些段的内容。
项目采用了模块化设计，主要包含以下几个部分：
Token.cs文件定义了Mips汇编语言的基本标记，包括寄存器、操作码、数据类型等。以下是部分关键定义：
public enum BaseType{ WORD, BYTE}public enum Instruction{ // R-type add, addu, sub, subu, and, or, xor, nor, slt, sltu, sll, srl, sra, sllv, srlv, srav, jr, // I-type addi, addiu, andi, ori, xori, sltiu, lui, lw, sw, beq, bne, bgtz, // J-type j, jal}public enum Register{ zero, at, v0, v1, a0, a1, a2, a3, t0, t1, t2, t3, t4, t5, t6, t7, s0, s1, s2, s3, s4, s5, s6, s7, t8, t9, k0, k1, gp, sp, fp, ra} Scanner.cs负责解析输入的汇编代码。它支持忽略空格和注释，以便提取有用的汇编指令。以下是其核心实现逻辑：
public class Scanner{ public string CurrentString; public string[] OpNums; public string OpType; public int innerLine; public int Line; public Scanner(string code, bool isData) { StreamReader = File.OpenText(code); IsData = isData; } public void ScanLine() { CurrentString = StreamReader.ReadLine(); // 删除空行 CurrentString = CurrentString.Trim(); while (CurrentString.Length == 0) { Line++; CurrentString = StreamReader.ReadLine(); if (CurrentString == null) return; CurrentString = CurrentString.Trim(); } // 删除整行注释 while (CurrentString.Trim().StartsWith("#")) { CurrentString = StreamReader.ReadLine(); } // 删除空行 CurrentString = CurrentString.Trim(); while (CurrentString.Length == 0) { Line++; CurrentString = StreamReader.ReadLine(); if (CurrentString == null) return; CurrentString = CurrentString.Trim(); } if (!IsData) { if (!CurrentString.Contains(":")) innerLine++; } Line++; // 删除一行里面的注释 List currentStringList = CurrentString.ToList(); int firstAnnotation = currentStringList.FindIndex(s => s == '#'); if (firstAnnotation != -1) { CurrentString = CurrentString.Substring(0, firstAnnotation); } try { int firstSpace = currentStringList.FindIndex(s => s == ' '); string opType = CurrentString.Substring(0, firstSpace); string opNum = CurrentString.Substring(firstSpace).Trim(); string[] opNums = opNum.Split(","); for (int i = 0; i < opNums.Length; i++) { opNums[i] = opNums[i].Trim(); } OpNums = opNums; OpType = opType; } catch (Exception ex) { } }} InstructionTranslator.cs负责将解析出的汇编指令转化为机器码。其核心逻辑包括：
以下是部分关键实现代码：
public class InstructionTranslator{ private Dictionary SymbolTable; private Dictionary LabelTable; private FileStream DataFileStream; private FileStream TextFileStream; private FileStream TextSegCodeStream; public InstructionTranslator(string codePath) { DataFileStream = new FileStream("data.txt", FileMode.Create, FileAccess.Write); TextFileStream = new FileStream("text.txt", FileMode.Create, FileAccess.Write); TextSegCodeStream = new FileStream("textSeg.txt", FileMode.Create, FileAccess.Write); Scanner = new Scanner(codePath, true); } public void Translate() { Scanner.ScanLine(); if (Scanner.CurrentString.Contains(".data")) { BuildSymbolTable(); } BuildLabelTable(); TranslateData(); TranslateText(); } private void TranslateData() { using (StreamWriter sw = new StreamWriter(DataFileStream)) { int currentAddr = 0; foreach (KeyValuePair var in SymbolTable) { if (!isByte) { if (var.Value.Type == BaseType.BYTE) { var.Value.Addr = "0x" + Convert.ToString(currentAddr | 0x10010000, 16); currentAddr += 1; if (var.Value.InitVal != null) { Buffer = Buffer.Insert(0, var.Value.InitVal.Substring(var.Value.InitVal.Length - 2, 2)); } isByte = true; } else { var.Value.Addr = "0x" + Convert.ToString(currentAddr | 0x10010000, 16); currentAddr += 4; sw.WriteLine(var.Value.InitVal); } } else { if (var.Value.Type == BaseType.BYTE) { var.Value.Addr = "0x" + Convert.ToString(currentAddr | 0x10010000, 16); currentAddr += 1; if (var.Value.InitVal != null) { Buffer = Buffer.Insert(0, var.Value.InitVal.Substring(var.Value.InitVal.Length - 2, 2)); } } else { isByte = false; if (Buffer != "") { while (Buffer.Length % 8 != 0) { Buffer = Buffer.Insert(0, "0"); } int i = Buffer.Length - 8; while (i >= 0) { data = Buffer.Substring(i, 8); sw.WriteLine(data); i -= 8; } } var.Value.Addr = "0x" + Convert.ToString(currentAddr | 0x10010000, 16); currentAddr += 4; sw.WriteLine(var.Value.InitVal); Buffer = ""; } } } } } private void TranslateText() { using (StreamWriter sw = new StreamWriter(TextFileStream)) { Scanner = new Scanner("textSeg.txt", false); while (true) { string[] instruction = Scanner.CurrentString.Split(","); if (instruction.Length == 0) break; string opType = instruction[0].Trim(); string[] opNums = instruction[1].Split(","); string hexCode = TranslateSentence(opType, opNums); sw.WriteLine(hexCode); } } }} 为了验证这个Mips汇编器的实现，我们可以使用以下汇编代码测试：
.text j main_loop beq $t1, $t2, mode_mode1 beq $t1, $t3, mode_mode2 beq $t1, $t4, mode_mode3 j main_loopmode_mode1: lw $s3, count lw $s4, mode1_init_rstate lw $s5, mode1_init_lstate addi $s6, $0, 0x00FFF000 addi $s7, $0, 0x000FFF00 beq $s3, $0, mode1_end beq $s4, $s6, mode1_start_dark mode1_start_light: sll $s4, $s4, 1 srl $s5, $s5, 1 jal model1_processor jal start_timer addi $s3, $s3, -1 j mode1_start_light mode1_start_dark: beq $s3, $0, mode1_end addi $t6, $0, 0x00000FFF beq $s4, $t6, mode1_start_light mode1_dark: srl $s4, $s4, 1 sll $s5, $s5, 1 jal model1_processor jal start_timer addi $s3, $s3, -1 j mode1_dark mode1_end: j main_loopmodel1_processor: and $t1, $s4, $s6 and $t2, $s5, $s7 srl $t1, $t1, 12 sll $t2, $t2, 4 sw $t1, t1 sw $t2, t2 add $t3, $t1, $t2 sw $t3, temp andi $t1, $t3, 0x0000FFFF sw $t1, 0xC60($28) andi $t1, $t3, 0x00FF0000 srl $t1, $t1, 16 sw $t1, 0xC62($28) jr $ramain_loop:
通过以上实现，我们成功构建了一个简易的Mips汇编器。虽然还有许多可以改进的地方，但这是我在大学生阶段完成的首个大型软件开发项目，给予了我宝贵的学习经验。未来，我希望能够在这个领域深入研究，开发更加功能完善的Mips汇编工具。
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