diff options
Diffstat (limited to 'Assembler/Assembler.cs')
| -rw-r--r-- | Assembler/Assembler.cs | 221 |
1 files changed, 199 insertions, 22 deletions
diff --git a/Assembler/Assembler.cs b/Assembler/Assembler.cs index 14a33fd..5df068d 100644 --- a/Assembler/Assembler.cs +++ b/Assembler/Assembler.cs @@ -10,6 +10,9 @@ public class Assembler public readonly BinaryWriter Writer; public readonly StringReader Reader; + private Dictionary<string, u16> _labels = new(); + private u16 _addressOffset = 0; + public Assembler(StringReader reader, BinaryWriter writer) { this.Reader = reader; @@ -20,11 +23,23 @@ public class Assembler { while (this.Reader.ReadLine() is { } line) { - string trimmedLine = line.Trim(); + string trimmedLine = line.Split(";")[0].Trim(); // Remove comments if (string.IsNullOrEmpty(trimmedLine) || trimmedLine.StartsWith(';')) continue; - this.ParseInstruction(trimmedLine); + if (trimmedLine.StartsWith(".org")) + { + // Handle .org directive + string orgValue = trimmedLine[5..].Trim(); + this._addressOffset = this.GetConstant(orgValue); + Console.WriteLine($"Setting address offset to {this._addressOffset:X4}"); + } + + else if (trimmedLine.EndsWith(":")) + this._labels[trimmedLine[..^1]] = (u16) (this.Writer.BaseStream.Position + this._addressOffset); + + else + this.ParseInstruction(trimmedLine); } } @@ -37,28 +52,40 @@ public class Assembler if (parts.Length > 2) throw new ArgumentException($"Invalid instruction format: {instruction}"); + u8 opcodeValue = this.ParseOpcode(opcode); + u8 m1 = 0, m2 = 0; if (parts.Length > 0) - { - m1 = this.ParseOperand(parts[0]); - if (parts.Length > 1) - m2 = this.ParseOperand(parts[1]); - } + m1 = this.ParseMode(parts[0]); + if (parts.Length > 1) + m2 = this.ParseMode(parts[1]); - switch (opcode) - { - case "NOP": - this.Writer.Write((u8) 0x00); - break; + Console.WriteLine($"Parsed instruction: {opcode} with modes {m1:X2}, {m2:X2} (at address {this.Writer.BaseStream.Position + this._addressOffset:X4})"); + this.WriteInstruction(opcodeValue, m1, m2); + if (parts.Length > 0) + this.WriteMode(m1, parts[0]); + if (parts.Length > 1) + this.WriteMode(m2, parts[1]); + } - default: - throw new NotSupportedException($"Unsupported opcode: {opcode}"); - } + private u8 ParseOpcode(string opcode) + { + return opcode switch + { + "NOP" => 0x00, "JMP" => 0x00, "MOV" => 0x00, + "RET" => 0x01, "CALL" => 0x01, "CMP" => 0x02, + "BR" => 0x02, "BZ" => 0x02, "LT" => 0x02, + "GT" => 0x03, + "INC" => 0x08, "ADD" => 0x08, + "DEC" => 0x09, + "MUL" => 0x0B, + _ => throw new ArgumentException($"Unknown opcode: {opcode}") + }; } - private u8 ParseOperand(string operand) + private u8 ParseMode(string mode) { - operand = operand.Trim(); + mode = mode.Trim(); bool IsRegister(string text) { @@ -81,26 +108,176 @@ public class Assembler return hardcodedRegisters.Contains(text); } - if (operand.StartsWith("@")) + if (this._labels.ContainsKey(mode)) + { + return 0x01; // Immediate + } + + if (mode.StartsWith("@")) { return 0x03; // Indirect } - if (operand.StartsWith("[") && operand.EndsWith("]")) + if (mode.StartsWith("[") && mode.EndsWith("]")) { - string inner = operand[1..^1].Trim(); + string inner = mode[1..^1].Trim(); if (inner.Contains("+")) return 0x07; // Register indirect with offset - + if (IsRegister(inner)) return 0x06; // Register indirect return 0x02; // Direct } - if (IsRegister(operand)) + if (IsRegister(mode)) return 0x05; // Register return 0x01; // Immediate } + + private void WriteInstruction(u8 opcode, u8 m1, u8 m2) + { + Write(opcode); + Write((u8) (m1 << 4 | m2)); // Combine m1 and m2 into a single byte + } + + private void WriteMode(u8 mode, string operand) + { + operand = operand.Trim(); + + switch (mode) + { + case 0x00: // Implicit + // No additional data needed + break; + + case 0x01: // Immediate + u16 immediateValue = this.GetConstant(operand); + this.Write(immediateValue); + break; + + case 0x02: // Direct + u16 directAddress = this.GetConstant(operand); // Remove brackets + this.Write(directAddress); + break; + + case 0x03: // Indirect + u16 indirectAddress = this.GetConstant(operand); // Remove brackets and @ + this.Write(indirectAddress); + break; + + case 0x04: // Relative + i16 relativeOffset = this.GetSignedConstant(operand); + Write(relativeOffset); + break; + + case 0x05: // Register + u8 regIndex = this.GetRegisterIndex(operand); + Write(regIndex); + break; + + case 0x06: // Register Indirect + u8 indirectRegIndex = this.GetRegisterIndex(operand); // Remove brackets + Write(indirectRegIndex); + break; + + case 0x07: // Register Indirect with Offset + u8 offsetRegIndex = this.GetRegisterIndex(operand[1..^1].Split('+')[0].Trim()); + i16 offsetValue = this.GetSignedConstant(operand[1..^1].Split('+')[1].Trim()); + Write(offsetRegIndex); + Write(offsetValue); + break; + } + } + private i16 GetSignedConstant(string value) + { + value = this.Clean(value); + + if (value.StartsWith("$")) + { + // Hexadecimal offset + return Convert.ToInt16(value[1..], 16); + } + else if (i16.TryParse(value, out i16 result)) + // Decimal offset + return result; + else + { + throw new ArgumentException($"Invalid offset value: {value}"); + } + } + private u8 GetRegisterIndex(string reg) + { + reg = this.Clean(reg); + + if (reg.StartsWith("V")) + if (u8.TryParse(reg[1..], out u8 index) && index < 0x3F) + return index; + + return reg switch + { + "AX" => 0x40, + "AH" => 0x41, + "AL" => 0x42, + "DX" => 0x43, + "DH" => 0x44, + "DL" => 0x45, + "LX" => 0x46, + "PC" => 0x50, + "SP" => 0x51, + _ => throw new ArgumentException($"Invalid register index: {reg}") + }; + } + private u16 GetConstant(string value) + { + value = this.Clean(value); + + if (this._labels.ContainsKey(value)) + { + // Label reference + return this._labels[value]; + } + if (value.StartsWith("$")) + { + // Hexadecimal constant (backwards) $1FFF + u16 x = Convert.ToUInt16(value[1..], 16); + return x; + } + else if (u16.TryParse(value, out u16 result)) + // Decimal constant + return result; + else + { + throw new ArgumentException($"Invalid constant value: {value}"); + } + } + + private string Clean(string value) + { + if (value.StartsWith("@")) + value = value[1..]; // Remove @ for indirect addressing + + if (value.StartsWith("[") && value.EndsWith("]")) + value = value[1..^1].Trim(); // Remove brackets for direct addressing + + return value.Trim(); + } + + private void Write(u16 value) + { + u16 swappedValue = (u16) ((value >> 8) | (value << 8)); + this.Writer.Write(swappedValue); + } + + private void Write(u8 value) + { + this.Writer.Write(value); + } + + private void Write(i16 value) + { + u16 swappedValue = (u16) ((value >> 8) | (value << 8)); + this.Writer.Write(swappedValue); + } }
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