MPL Bytecode Compiler Code

(* MPL - MICRO PROGRAMMING LANGUAGE / COPYRIGHT (C) 2017-2018 DEREK JOHN EVANS *)

FUNCTION ISO(O:OPER):BOOL; BEGIN
  IF GO=O THEN BEGIN NEXT; ISO:=TRUE END ELSE ISO:=FALSE END;

FUNCTION NUMB:SHORT; VAR I:SHORT; PI:PSHORT; NEG:BOOL; BEGIN
  I:=0; NEG:=GO=OSUB2; IF GK=K4 THEN NEXT;
  IF GO=OLIM2 THEN BEGIN I:=GI; NEXT END
  ELSE IF LOC(PI) THEN BEGIN IF GS[1]='.' THEN BEGIN I:=PI^; NEXT END
    ELSE BEGIN NEXT; IF ISO(OLEA1) THEN I:=PI^
      ELSE I:=GX.I[PI^ SHR 1] END END ELSE ERR(EMIS);
  IF NEG THEN NUMB:=-I ELSE NUMB:=I END;

PROCEDURE EXPR; FORWARD; PROCEDURE COMP; FORWARD;

PROCEDURE ELEM(K:KIND; BY1:BOOL); VAR I:SHORT; PI:PSHORT; O:OPER; STEP:BOOL;
LABEL 0; BEGIN
  IF(K>K2)THEN BEGIN ELEM(PRED(K),TRUE);
    WHILE K=GK DO BEGIN O:=GO; NEXT; O1(OSET1); ELEM(PRED(K),TRUE); O1(O) END
  END ELSE BEGIN CASE GO OF
    OIFEQ:BEGIN NEXT; OI(OTST2,NUMB) END;
    OSET1:BEGIN NEXT; EXPR; IF GO=OSET2 THEN NEXT ELSE ERR(ESYN) END;
    OSET4:BEGIN NEXT; EXPR; O1(ODONE) END;
    OLOOP:BEGIN I:=GP; NEXT; EXPR; O3(OIFNE,I) END;
    OLIM2:BEGIN OL(GI); NEXT END; OLIM3:BEGIN O1(OLIM3); WS; NEXT END;
    OLD11,OLD12:BEGIN BY1:=GO=OLD11; NEXT; ELEM(K0,BY1);
      IF (K=GK)AND(K=K2) THEN BEGIN O1(OSET1); O:=GO; NEXT; EXPR;
        IF BY1 THEN O1(PRED(O)) ELSE O1(O) END ELSE OT(OLD12,BY1) END
    ELSE BEGIN O:=GO; IF GK IN [K3,K4,K5,K6(*,K7*)] THEN BEGIN
      NEXT; ELEM(K1,TRUE); O1(PRED(O)) END
      ELSE BEGIN STEP:=O IN [OAD2A,OSU2A]; IF STEP THEN NEXT; IF LOC(PI) THEN
        IF GS[1]='.' THEN BEGIN IF STEP THEN ERR(ESYN); OL(PI^); NEXT END
        ELSE BEGIN IF PI^<0 THEN OI(OLEA2,PI^) ELSE OL(PI^); NEXT;
          IF STEP THEN OT(O,BY1) ELSE IF (K=GK)AND(K=K2) THEN BEGIN
            O1(OSET1); O:=GO; NEXT; EXPR; O1(O) END
          ELSE CASE GO OF OAD2A:BEGIN OT(OADA2,BY1); NEXT END;
            OSU2A:BEGIN OT(OSUA2,BY1); NEXT END; OLEA1:NEXT
            ELSE O1(ODREF) END END ELSE ERR(EMIS) END END END;
  IF(K>K0)THEN BEGIN 0:CASE GO OF
    OLD11,OLD12:BEGIN O1(OSET1); BY1:=GO=OLD11; NEXT; ELEM(K0,TRUE);
      IF(K=GK)AND(K=K2)THEN BEGIN OT(OIDX2,BY1); O:=GO; NEXT; EXPR;
        IF BY1 THEN O1(PRED(O)) ELSE O1(O) END ELSE OT(OLD22,BY1); GOTO 0 END;
    OSET1:BEGIN O1(OSET1); NEXT; I:=1; IF GO<>OSET2 THEN
      REPEAT EXPR; O1(OSET1); I:=SUCC(I) UNTIL NOT ISO(OMORE);
      OL(I); O1(OMORE); IF ISO(OSET2) THEN GOTO 0 ELSE ERR(ESYN) END END
END END END;

PROCEDURE EXPR;
VAR EX,JP,EQ:SHORT; O:OPER; BEGIN EX:=GP;
  IF GO=OINIT THEN BEGIN REPEAT NEXT; EXPR UNTIL GO<>OSTOP;
    IF GO=ODONE THEN NEXT ELSE ERR(ESYN) END ELSE ELEM(K8,TRUE);
  IF GO IN [OLOOP,OIFEQ] THEN BEGIN O:=GO; EQ:=GP; O3(OIFEQ,0); NEXT; EXPR;
    CASE O OF OLOOP:BEGIN O3(OLOOP,EX); OP(EQ,OIFEQ,GP) END;
      OIFEQ:IF GO=OIFNE THEN BEGIN JP:=GP; O3(OLOOP,0); OP(EQ,OIFEQ,GP);
        NEXT; EXPR; OP(JP,OLOOP,GP) END ELSE OP(EQ,OIFEQ,GP) END END END;

PROCEDURE BODY;
VAR AIMP,AVAR:BOOL; PI:PSHORT; I,LZ:SHORT; LR:REF;
BEGIN WHILE NOT(GO IN [OSTOP,ODONE])AND(GE=0) DO CASE GO OF
  ODREF:REPEAT NEXT; COMP; NEXT UNTIL GO<>OMORE;
  OINIT:BEGIN LR:=GR; LZ:=GZ; NEXT; BODY; GR:=LR; GZ:=LZ;
    IF GO=ODONE THEN NEXT ELSE ERR(ESYN) END
  ELSE BEGIN IF ODD(GP) THEN O1(OADD1); AIMP:=ISO(OLD22);
    WRITE(CHR(13),GP:5,': ',GS); CLREOL;
    IF GO<>OLIM1 THEN ERR(ESYN) ELSE BEGIN AVAR:=GS[1]<>'.';
      IF AIMP THEN IF LOC(PI) THEN IF AVAR THEN GX.I[PI^ SHR 1]:=GP
        ELSE ERR(ESYN) ELSE ERR(EMIS) ELSE BEGIN ADD(PI); PI^:=GP END;
      IF GE=0 THEN BEGIN NEXT; CASE GO OF
        OIFNE:BEGIN NEXT; PI^:=NUMB END;
        OSET4:REPEAT NEXT; CASE GO OF
            OLD11:BEGIN NEXT; GP:=GP+NUMB END;
            OLD12:BEGIN NEXT; GP:=GP+NUMB SHL 1 END;
            OLIM3:BEGIN WS; NEXT END ELSE WI(NUMB) END UNTIL GO<>OMORE;
        OSET1:BEGIN (*WRITELN;*) IF AVAR THEN IF NOT AIMP THEN WI(GP+2); NEXT;
          LR:=GR; LZ:=GZ; I:=1; IF GO<>OSET2 THEN
          REPEAT REPEAT IF GO<>OSTOP THEN IF GS[1]='.' THEN ERR(ESYN)
            ELSE BEGIN ADD(PI); PI^:=-I; NEXT; CASE GO OF
              OLD11:BEGIN NEXT; I:=I+SUCC(NUMB) SHR 1 END;
              OLD12:BEGIN NEXT; I:=I+NUMB END ELSE I:=SUCC(I) END;
            END UNTIL NOT ISO(OMORE) UNTIL NOT ISO(OSTOP);
          IF NOT ISO(OSET2) THEN ERR(ESYN); O2(OINIT,CHR(I)); EXPR; O1(ODONE);
          GR:=LR; GZ:=LZ END ELSE IF AVAR THEN ERR(ESYN) END END END END END END;

PROCEDURE COMP; VAR T:TEXT; LT:PTEXT; LC:CHAR; PI:PSHORT; BEGIN
  LT:=GT; LC:=GC; GT:=PTR(ADDR(T)); GC:=CHR(32); GO:=OLIM1;
  IF NOT LOC(PI) THEN BEGIN ADD(PI);
    IF ENTER THEN BEGIN NEXT; BODY; LEAVE END ELSE ERR(EMIS) END;
  GT:=LT; GC:=LC; END;