Changeset 184 for branches/virtualcpu4/UAssembler.pas

Timestamp:

Apr 25, 2019, 4:20:43 PM (5 years ago)

Author:

chronos

Message:

• Added: Basic assembler window.

File:

• branches/virtualcpu4/UAssembler.pas (modified) (2 diffs)

branches/virtualcpu4/UAssembler.pas

@@ -6 +6 @@
 
 uses
-  Classes, SysUtils;
+  Classes, SysUtils, fgl, UCpu, UOpcode, UInstructionWriter;
 
 type
+  TErrorEvent = procedure (Text: string) of object;
+
+  { TParser }
+
+  TParser = class
+  private
+    FOnError: TErrorEvent;
+    procedure Error(Text: string);
+  public
+    Text: string;
+    procedure Expect(Text: string);
+    function ReadNext: string;
+    function EndOfText: Boolean;
+    property OnError: TErrorEvent read FOnError write FOnError;
+  end;
+
+  TLabel = class
+    Name: string;
+    Address: QWord;
+  end;
+
+  TLabels = class(TFPGObjecTList<TLabel>)
+
+  end;
+
   { TAssembler }
 
   TAssembler = class
+  private
+    FOnError: TErrorEvent;
+    OpcodeDefs: TOpcodeDefs;
+    procedure Error(Text: string);
+    procedure ParseParam(Param: TOpcodeParam);
+  public
+    Parser: TParser;
+    Labels: TLabels;
     Source: TStringList;
-    Dest: array of Byte;
+    InstructionWriter: TInstructionWriter;
     procedure Compile;
+    constructor Create;
+    destructor Destroy; override;
+    property OnError: TErrorEvent read FOnError write FOnError;
   end;
 
@@ -20 +56 @@
 implementation
 
+{ TParser }
+
+procedure TParser.Error(Text: string);
+begin
+  if Assigned(FOnError) then FOnError(Text);
+end;
+
+procedure TParser.Expect(Text: string);
+var
+  Next: string;
+begin
+  Next := ReadNext;
+  if Next <> Text then
+    Error('Expected ' + Text + ' but ' + Next + ' found');
+end;
+
+function TParser.ReadNext: string;
+var
+  P: Integer;
+begin
+  Text := Trim(Text);
+  P := 1;
+  if (Length(Text) > 0) and (Text[P] = ',') then begin
+    Result := Text[P];
+    Delete(Text, 1, 1);
+  end else begin
+    while (P <= Length(Text)) and (Text[P] <> ' ') and (Text[P] <> ',') do Inc(P);
+    Result := Copy(Text, 1, P - 1);
+    Delete(Text, 1, P - 1);
+  end;
+end;
+
+function TParser.EndOfText: Boolean;
+begin
+  Result := Text = '';
+end;
+
 { TAssembler }
 
+procedure TAssembler.Error(Text: string);
+begin
+  if Assigned(FOnError) then FOnError(Text);
+end;
+
+procedure TAssembler.ParseParam(Param: TOpcodeParam);
+var
+  Reg: TRegIndex;
+  Addr: QWord;
+  Next: string;
+begin
+  if Param = prReg then begin
+    Next := Parser.ReadNext;
+    if (Length(Next) > 1) and (Next[1] = 'R') then
+      Reg := StrToInt(Copy(Next, 2, Length(Next)))
+    else Error('Expected register name but found ' + Next);
+    InstructionWriter.Write8(Reg);
+  end else
+  if Param = prData then begin
+    Next := Parser.ReadNext;
+    InstructionWriter.WriteData(StrToInt(Next));
+  end else
+  if Param = prAddr then begin
+    Next := Parser.ReadNext;
+    InstructionWriter.WriteAddress(StrToInt(Next));
+  end else
+  if Param = prAddrRel then begin
+    Next := Parser.ReadNext;
+    InstructionWriter.WriteAddress(StrToInt(Next));
+  end;
+end;
+
 procedure TAssembler.Compile;
+var
+  I: Integer;
+  NewLabel: TLabel;
+  Next: string;
+  OpcodeDef: TOpcodeDef;
 begin
+  InstructionWriter.Init;
+  Labels.Clear;
+  for I := 0 to Source.Count - 1 do begin
+    Parser.Text := Source[I];
+    Next := Parser.ReadNext;
+    if (Length(Next) > 0) and (Next[Length(Next)] = ':') then begin
+      NewLabel := TLabel.Create;
+      NewLabel.Name := Copy(Next, 1, Length(Next) - 1);
+      //NewLabel.Address := ;
+      Labels.Add(NewLabel);
+      Next := Parser.ReadNext;
+    end;
+    OpcodeDef := OpcodeDefs.SearchByName(Next);
+    if Assigned(OpcodeDef) then begin
+      InstructionWriter.Write8(Byte(OpcodeDef.Opcode));
+      ParseParam(OpcodeDef.Param1);
+      if OpcodeDef.Param2 <> prNone then begin
+        Parser.Expect(',');
+        ParseParam(OpcodeDef.Param2);
+        if OpcodeDef.Param3 <> prNone then begin
+          Parser.Expect(',');
+          ParseParam(OpcodeDef.Param3);
+        end;
+      end;
+    end else Error('Unknown instruction ' + Next);
+  end;
+end;
 
+constructor TAssembler.Create;
+begin
+  OpcodeDefs := TOpcodeDefs.Create;
+  Source := TStringList.Create;
+  Labels := TLabels.Create;
+  Parser := TParser.Create;
+  Parser.OnError := Error;
+  InstructionWriter := TInstructionWriter.Create;
+end;
+
+destructor TAssembler.Destroy;
+begin
+  FreeAndNil(InstructionWriter);
+  FreeAndNil(Parser);
+  FreeAndNil(Labels);
+  FreeAndNil(Source);
+  FreeAndNil(OpcodeDefs);
+  inherited Destroy;
 end;