MODULE cradle9;

(* Part 3                                             *)
(* variables and numbers with mutiples digits         *)

(* <factor> ::= [+|-]digit | (<expression>)           *)
(* <expression> ::= <term> [<addop> <term>]*          *)
(* <term> ::= <factor> [ <mulop> <factor ]*           *)

IMPORT SYSTEM, Strings, InOut,WholeStr, CharClass, FIO ;

CONST 
  TAB = CHR(9);
  
VAR 
  Look       : CHAR;
  ErrorCode  : CARDINAL;
  chaine     : ARRAY[0..255] OF CHAR;  
  nomFichier : ARRAY [0..255] OF CHAR;
  fichier    : FIO.File;
  
PROCEDURE GetChar;

BEGIN 
  InOut.Read(Look)
END GetChar;

PROCEDURE Error (s : ARRAY OF CHAR);

BEGIN 
  InOut.WriteLn;
  InOut.Write(CHR(8));
  InOut.Write(TAB);
  InOut.WriteString("Error : ");
  InOut.WriteString(s);
  InOut.Write(".");
END Error;


PROCEDURE Abort (s : ARRAY OF CHAR);

BEGIN 
  Error(s);
  HALT
END Abort;

PROCEDURE Expected (s : ARRAY OF CHAR);

VAR 
  chaine : ARRAY [0..255] OF CHAR;

BEGIN 
  Strings.Concat(s, " Expected ",chaine);
  Abort (chaine)
END Expected;

PROCEDURE Match ( x : CHAR );

BEGIN 
  IF Look = x THEN 
    GetChar
  ELSE
    Strings.Concat("''",Strings.String1(x),chaine);
    Strings.Concat(chaine, "''", chaine);
    Expected(chaine)  
  END;
END Match;

PROCEDURE IsAddop(c: CHAR): BOOLEAN;

BEGIN
  RETURN (c = "+") OR (c = "-")
END IsAddop;

PROCEDURE IsAlpha (c : CHAR ) : BOOLEAN;

BEGIN 
  RETURN CharClass.IsUpper(CAP(c)) 
END IsAlpha;

PROCEDURE IsDigit (c : CHAR) : BOOLEAN;

BEGIN 
 RETURN CharClass.IsNumeric(c)
END IsDigit;

PROCEDURE GetName (VAR s : ARRAY OF CHAR);

BEGIN 
  IF NOT IsAlpha(Look) THEN 
    ErrorCode := 1;
    Expected('Name');
  END;
  Strings.Assign(Strings.String1(CAP(Look)),s);
  GetChar;
END GetName;

PROCEDURE GetNum (VAR c : CHAR);

BEGIN 
  IF NOT IsDigit(Look) THEN 
    ErrorCode := 1;
    Expected('Integer');
  END;
  c :=  Look;
  GetChar;
END GetNum;

PROCEDURE Emit (s : ARRAY OF CHAR);

BEGIN 
  FIO.WriteString(fichier,s);
END Emit;

PROCEDURE EmitLn (s : ARRAY OF CHAR );

BEGIN 
  FIO.WriteString(fichier,s);
  FIO.WriteLine(fichier);
END EmitLn;

(******************************************************)
(*        le parser commence ici *********************)
(******************************************************)

(* <factor> ::= [+|-]digit | (<expression>)           *)
(* <expression> ::= <term> [<addop> <term>]*          *)
(* <term> ::= <factor> [ <mulop> <factor ]*           *)
(* adding unary sign, + and -                         *)

PROCEDURE Expression; FORWARD;

PROCEDURE Factor;
(* Parse and Translate a Math Factor *)
(* in cradle5, it was     Term       *)

VAR 
  c : CHAR;

BEGIN
  IF Look = '(' THEN 
    (* (expression)  *)
    Match('(');
    Expression;
    Match(')'); 
  ELSE   
    (*  digit *)
    (* EmitLn('MOVE #' + GetNum + ',D0')*)
    GetNum(c);
    Strings.Concat(TAB,"mov rax,", chaine);
    Strings.Concat(chaine, Strings.String1(c), chaine);
    EmitLn(chaine)
  END  
END Factor;


PROCEDURE  Multiply;
(* Recognize and Translate a Multiply *)

BEGIN 
  Match('*');
  Factor;
  (*EmitLn('MULS (SP)+,D0');*)
  Strings.Concat(TAB,"pop rbx", chaine);
  EmitLn(chaine);
  Strings.Concat(TAB,"imul rax, rbx", chaine);
  EmitLn(chaine);
END Multiply;


PROCEDURE  Divide;
(* Recognize and Translate a Divide *)

BEGIN 
  Match('/');
  Factor;
  (*EmitLn('MOVE (SP)+,D1');*)
  (*EmitLn('DIVS D1,D0');*)
  Strings.Concat(TAB,"pop rbx", chaine);
  EmitLn(chaine);
  Strings.Concat(TAB,"div rax, rbx", chaine);
  EmitLn(chaine);
END Divide;


PROCEDURE Term;
(* Parse and Translate a Math Term*)

VAR 
  c : CHAR;

BEGIN 
  Factor;
  WHILE (Look = '*') OR (Look = '/') DO  
    (*EmitLn('MOVE D0,-(SP)');*)
    Strings.Concat(TAB,"push rax",chaine);
    EmitLn(chaine);
    CASE  Look OF 
      '*': Multiply; |
      '/': Divide;
    ELSE  
      Expected('Mulop');
    END;
  END;
END Term;

PROCEDURE Add;

BEGIN 
  Match('+');
  Term;
  Strings.Concat(TAB,"pop rbx", chaine);
  EmitLn(chaine);
  Strings.Concat(TAB,"add rax, rbx", chaine);
  EmitLn(chaine);
END Add;

PROCEDURE Substract;

BEGIN 
  Match ('-');
  Term;
  Strings.Concat(TAB,"pop rbx", chaine);
  EmitLn(chaine);
  Strings.Concat(TAB,"sub rax, rbx", chaine);
  EmitLn(chaine);
  Strings.Concat(TAB,"neg rax", chaine);
  EmitLn(chaine);
END Substract;

PROCEDURE Expression;
(* Parse and Translate an Expression*)

BEGIN 
  IF IsAddop (Look) THEN 
    Strings.Concat(TAB,"xor rax, rax",chaine);
    EmitLn(chaine);
  ELSE
    Term;
  END;
  WHILE (Look = '+') OR (Look = '-') DO 
    (* EmitLn('MOVE D0,D1');       version 1                 *)
    (* EmitLn('MOVE D0,-(SP)');    version utilisant la pile *)
    Strings.Concat(TAB,"push rax",chaine);
    EmitLn(chaine);
    CASE Look OF 
      '+' : Add;   |
      '-' : Substract;
    ELSE
      Expected ("Addop ");
    END;   
  END;   
END Expression;

(*****************fin du parser ************)

PROCEDURE Init;

VAR
  OK : BOOLEAN;

BEGIN 
  (* création d'un fichier asm *)
  nomFichier := "cradleasm9.asm";
  fichier := FIO.OpenForRandom(nomFichier,TRUE,TRUE );
  IF NOT FIO.IsNoError(fichier) THEN 
    InOut.WriteString("Echec de création du fichier asm");
    HALT
  END;
  ErrorCode := 0;
  GetChar;
  EmitLn("[BITS 64]");
  EmitLn("");
  EmitLn("; begining of the assembly program");
  EmitLn("");
  EmitLn("; sys calls");
  EmitLn("%define SYS_EXIT 60");
  EmitLn("%define SYS_WRITE 1");
  EmitLn("");
  EmitLn("%define STD_IN 0");
  EmitLn("%define STD_OUT 1");
  EmitLn("%define STD_ERR 2");
  EmitLn("");
  EmitLn("section .bss");
  EmitLn("; nada");
  EmitLn("");
  EmitLn("section .data");
  EmitLn("");
  EmitLn("section .text");
  EmitLn("global _start");
  EmitLn("");
  EmitLn("_start:");
  
END Init;

PROCEDURE EndCompile;
  
BEGIN 
  EmitLn("");
  EmitLn("; end of program");
  Strings.Concat(TAB, "mov rdi,0",chaine);
  EmitLn(chaine);
  Strings.Concat(TAB, "mov rax,SYS_EXIT",chaine);
  EmitLn(chaine);
  Strings.Concat(TAB,"syscall",chaine);
  EmitLn(chaine);
  FIO.Close(fichier)
END EndCompile;

BEGIN 
  InOut.WriteString("Début de compilation");
  InOut.WriteLn;
  InOut.WriteString("Entrez le source : ");
  Init;
  Expression;
  EndCompile;
END cradle9.