📄 unit1.cpp
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i=POSITION(ID,TX);
if (i==0) Error(11);
else
if (TABLE[i].KIND==PROCEDUR)
GEN(CAL,LEV-TABLE[i].vp.LEVEL,TABLE[i].vp.ADR);
else Error(15);
GetSym();
}
break;
case IFSYM:
/*GetSym();
CONDITION(SymSetUnion(SymSetNew(THENSYM,DOSYM),FSYS),LEV,TX);
if (SYM==THENSYM) GetSym();
else Error(16);
CX1=CX; GEN(JPC,0,0);
STATEMENT(FSYS,LEV,TX); CODE[CX1].A=CX; */
//改为
GetSym();
CONDITION(SymSetUnion(SymSetNew(THENSYM),FSYS),LEV,TX);
if (SYM==THENSYM) GetSym();
else Error(16);
CX1=CX; //由于cx地址随时都会变,所以需要把值赋给cx1保存,以为回填做准备
GEN(JPC,0,0);//生成目标代码,有条件转向,当if条件为真时,顺序执行,假时转向下一条指令
STATEMENT(SymSetAdd(ELSESYM,FSYS),LEV,TX); //添加else的类型在出错恢复集合中
CX2=CX;
GEN(JMP,0,0); //无条件转向,转出整个if语句
CODE[CX1].A=CX; //回填CX1为此时CX的地址
if(SYM==ELSESYM)
{
GetSym();
STATEMENT(FSYS,LEV,TX);
}
CODE[CX2].A=CX; //回填CX2为此时CX的地址
break;
case BEGINSYM:
GetSym();
STATEMENT(SymSetUnion(SymSetNew(SEMICOLON,ENDSYM),FSYS),LEV,TX);
while (SymIn(SYM, SymSetAdd(SEMICOLON,STATBEGSYS))) {
if (SYM==SEMICOLON) GetSym();
else Error(10);
STATEMENT(SymSetUnion(SymSetNew(SEMICOLON,ENDSYM),FSYS),LEV,TX);
}
if (SYM==ENDSYM) GetSym();
else Error(17);
break;
case WHILESYM:
CX1=CX; GetSym(); CONDITION(SymSetAdd(DOSYM,FSYS),LEV,TX);
CX2=CX; GEN(JPC,0,0);
if (SYM==DOSYM) GetSym();
else Error(18);
STATEMENT(FSYS,LEV,TX);
GEN(JMP,0,CX1);
CODE[CX2].A=CX;
break;
case PLPL:
GetSym();
i=POSITION(ID,TX);
if (i==0) Error(11);
else
if (TABLE[i].KIND!=VARIABLE)
{ /*ASSIGNMENT TO NON-VARIABLE*/
Error(12); i=0;
}
GEN(LOD,LEV-TABLE[i].vp.LEVEL,TABLE[i].vp.ADR);
GEN(LIT,0,1);
GEN(OPR,0,2);
GEN(STO,LEV-TABLE[i].vp.LEVEL,TABLE[i].vp.ADR);
TABLE[i].VAL=NUM;
GEN(LOD,LEV-TABLE[i].vp.LEVEL,TABLE[i].vp.ADR);
GetSym();
break;
case MIMI:
GetSym();
i=POSITION(ID,TX);
if (i==0) Error(11);
else
if (TABLE[i].KIND!=VARIABLE)
{ /*ASSIGNMENT TO NON-VARIABLE*/
Error(12); i=0;
}
GEN(LOD,LEV-TABLE[i].vp.LEVEL,TABLE[i].vp.ADR);
GEN(LIT,0,1);
GEN(OPR,0,3);
GEN(STO,LEV-TABLE[i].vp.LEVEL,TABLE[i].vp.ADR);
TABLE[i].VAL=NUM;
GEN(LOD,LEV-TABLE[i].vp.LEVEL,TABLE[i].vp.ADR);
GetSym();
break;
case FORSYM:
GetSym();
if(SYM!=IDENT)Error(8);
i=POSITION(ID,TX);
if (i==0) Error(11);
else
if (TABLE[i].KIND!=VARIABLE) { /*ASSIGNMENT TO NON-VARIABLE*/
Error(12); i=0;
}
GetSym();
if (SYM==BECOMES)
{
GetSym();
EXPRESSION(SymSetUnion(SymSetNew (TOSYM,DOSYM,DOWNTOSYM),FSYS),LEV,TX);
if (i!=0) GEN(STO,LEV-TABLE[i].vp.LEVEL,TABLE[i].vp.ADR);
TABLE[i].VAL=NUM;
}
else Error(13);
if(SYM==TOSYM)
{
GetSym();
EXPRESSION(SymSetUnion(SymSetNew(TOSYM,DOSYM),FSYS),LEV,TX);
if(SYM==DOSYM)GetSym();
else Error(18);
CX1=CX;
GEN(OPR,0,17);
GEN(LOD,LEV-TABLE[i].vp.LEVEL,TABLE[i].vp.ADR);
GEN(OPR,0,11); //次栈顶是否大于栈顶
CX2=CX;
GEN(JPC,0,0);
STATEMENT(FSYS,LEV,TX);
GEN(LOD,LEV-TABLE[i].vp.LEVEL,TABLE[i].vp.ADR);
GEN(LIT,0,1);
GEN(OPR,0,2);
GEN(STO,LEV-TABLE[i].vp.LEVEL,TABLE[i].vp.ADR);
TABLE[i].VAL=TABLE[i].VAL+1;
GEN(JMP,0,CX1);
CODE[CX2].A=CX;
//GetSym();
}
if(SYM==DOWNTOSYM)
{
GetSym();
EXPRESSION(SymSetUnion(SymSetNew(DOWNTOSYM,DOSYM),FSYS),LEV,TX);
if(SYM==DOSYM)GetSym();
else Error(18);
CX1=CX;
GEN(OPR,0,17);
GEN(LOD,LEV-TABLE[i].vp.LEVEL,TABLE[i].vp.ADR);
GEN(OPR,0,13); //次栈顶是否大于栈顶
CX2=CX;
GEN(JPC,0,0);
STATEMENT(FSYS,LEV,TX);
GEN(LOD,LEV-TABLE[i].vp.LEVEL,TABLE[i].vp.ADR);
GEN(LIT,0,1);
GEN(OPR,0,3);
GEN(STO,LEV-TABLE[i].vp.LEVEL,TABLE[i].vp.ADR);
TABLE[i].VAL=NUM;
GEN(JMP,0,CX1);
CODE[CX2].A=CX;
//GetSym();
}
break;
}
TEST(FSYS,SymSetNULL(),19);
} /*STATEMENT*/
//---------------------------------------------------------------------------
void Block(int LEV, int TX, SYMSET FSYS) {
int DX=3; /*DATA ALLOCATION INDEX*/
int TX0=TX; /*INITIAL TABLE INDEX*/
int CX0=CX; /*INITIAL CODE INDEX*/
TABLE[TX].vp.ADR=CX; GEN(JMP,0,0);
if (LEV>LEVMAX) Error(32);
do {
if (SYM==CONSTSYM) {
GetSym();
do {
ConstDeclaration(LEV,TX,DX);
while (SYM==COMMA) {
GetSym(); ConstDeclaration(LEV,TX,DX);
}
if (SYM==SEMICOLON) GetSym();
else Error(5);
}while(SYM==IDENT);
}
if (SYM==VARSYM) {
GetSym();
do {
VarDeclaration(LEV,TX,DX);
while (SYM==COMMA) { GetSym(); VarDeclaration(LEV,TX,DX); }
if (SYM==SEMICOLON) GetSym();
else Error(5);
}while(SYM==IDENT);
}
if (SYM==CHARSYM) {
GetSym();
do {
CharDeclaration(LEV,TX,DX);
while (SYM==COMMA) { GetSym(); CharDeclaration(LEV,TX,DX); }
if (SYM==SEMICOLON) GetSym();
else Error(5);
}while(SYM==IDENT);
}
if (SYM==REALSYM) {
GetSym();
do {
RealDeclaration(LEV,TX,DX);
while (SYM==COMMA) { GetSym(); RealDeclaration(LEV,TX,DX); }
if (SYM==SEMICOLON) GetSym();
else Error(5);
}while(SYM==IDENT);
}
while ( SYM==PROCSYM) {
GetSym();
if (SYM==IDENT) { ENTER(PROCEDUR,LEV,TX,DX); GetSym(); }
else Error(4);
if (SYM==SEMICOLON) GetSym();
else Error(5);
Block(LEV+1,TX,SymSetAdd(SEMICOLON,FSYS));
if (SYM==SEMICOLON) {
GetSym();
TEST(SymSetUnion(SymSetNew(IDENT,PROCSYM),STATBEGSYS),FSYS,6);
}
else Error(5);
}
TEST(SymSetAdd(IDENT,STATBEGSYS), DECLBEGSYS,7);
}while(SymIn(SYM,DECLBEGSYS));
CODE[TABLE[TX0].vp.ADR].A=CX;
TABLE[TX0].vp.ADR=CX; /*START ADDR OF CODE*/
TABLE[TX0].vp.SIZE=DX; /*SIZE OF DATA SEGMENT*/
GEN(INI,0,DX);
STATEMENT(SymSetUnion(SymSetNew(SEMICOLON,ENDSYM),FSYS),LEV,TX);
GEN(OPR,0,0); /*RETURN*/
TEST(FSYS,SymSetNULL(),8);
ListCode(CX0);
} /*Block*/
//---------------------------------------------------------------------------
int BASE(int L,int B,float S[]) {
int B1=B; /*FIND BASE L LEVELS DOWN*/
while (L>0) { B1=S[B1]; L=L-1; }
return B1;
} /*BASE*/
//---------------------------------------------------------------------------
void Interpret() {
const STACKSIZE = 500;
int P,B,T; /*PROGRAM BASE TOPSTACK REGISTERS*/
INSTRUCTION I;
float S[STACKSIZE]; /*DATASTORE*/
Form1->printfs("~~~ RUN PL0 ~~~");
fprintf(FOUT,"~~~ RUN PL0 ~~~\n");
T=0; B=1; P=0;
S[1]=0; S[2]=0; S[3]=0;
do {
I=CODE[P]; P=P+1;
switch (I.F) {
case LIT: T++; S[T]=I.A; break;
case OPR:
switch ((int)I.A) { /*OPERATOR*/
case 0: /*RETURN*/ T=B-1; P=S[T+3]; B=S[T+2]; break;
case 1: S[T]=-S[T]; break;
case 2: T--; S[T]=S[T]+S[T+1]; break;
case 3: T--; S[T]=S[T]-S[T+1]; break;
case 4: T--; S[T]=S[T]*S[T+1]; break;
case 5: T--; S[T]=S[T] / S[T+1]; break;
case 6: S[T]=((int)S[T]%2!=0); break;
case 8: T--; S[T]=S[T]==S[T+1]; break;
case 9: T--; S[T]=S[T]!=S[T+1]; break;
case 10: T--; S[T]=S[T]<S[T+1]; break;
case 11: T--; S[T]=S[T]>=S[T+1]; break;
case 12: T--; S[T]=S[T]>S[T+1]; break;
case 13: T--; S[T]=S[T]<=S[T+1]; break;
case 14: fprintf(FOUT,"%f\n",S[T]);Form1->printrs("",S[T]);
T--;
break;
case 15: /*Form1->printfs(""); fprintf(FOUT,"\n"); */ break;
case 16: T++; S[T]=InputBox("输入","请键盘输入：", 0).ToInt();
Form1->printls("? ",S[T]); fprintf(FOUT,"? %d\n",S[T]);
break;
//以下是增加部分
case 17: T++; S[T]=S[T-1]; break;//复制栈顶元素到栈顶
case 18: T--; break;
case 19: //输出字符
Form1->printcs(S[T]);
fprintf(FOUT,"%c\n",(char)S[T]); T--;
break;
case 20: //输入实数
T++; S[T]=InputBox("输入","请键盘输入：", 0).ToDouble();
Form1->printrs("? ",S[T]); fprintf(FOUT,"? %f\n",S[T]);
break;
case 21: //输入字符
T++;
AnsiString css=InputBox("输入","请键盘输入：", 0);//.AnsiLastChar();
char *buf=css.c_str();
S[T]=(int)buf[0]; Form1->printcs('?');
Form1->printcs((char)S[T]); fprintf(FOUT,"? %c\n",(char)S[T]);
break;
}
break;
case LOD: T++; S[T]=S[BASE(I.L,B,S)+(int)I.A];aa=(int)S[T]; break;
case STO: S[BASE(I.L,B,S)+(int)I.A]=S[T]; T--; break;
case CAL: /*GENERAT NEW Block MARK*/
S[T+1]=BASE(I.L,B,S); S[T+2]=B; S[T+3]=P;
B=T+1; P=I.A; break;
case INI: T=T+I.A; break;
case JMP: P=I.A; break;
case JPC: if (S[T]==0) P=I.A; T--; break;
} /*switch*/
}while(P!=0);
Form1->printfs("~~~ END PL0 ~~~");
fprintf(FOUT,"~~~ END PL0 ~~~\n");
} /*Interpret*/
//---------------------------------------------------------------------------
void __fastcall TForm1::ButtonRunClick(TObject *Sender) {
for (CH=' '; CH<='^'; CH++) SSYM[CH]=NUL;
strcpy(KWORD[ 1],"BEGIN"); strcpy(KWORD[ 2],"CALL");
strcpy(KWORD[ 3],"CHAR");
strcpy(KWORD[ 4],"CONST"); strcpy(KWORD[ 5],"DO");
strcpy(KWORD[ 6],"DOWNTO"); strcpy(KWORD[ 7],"ELSE");
strcpy(KWORD[ 8],"END"); strcpy(KWORD[ 9],"FOR");
strcpy(KWORD[10],"IF"); strcpy(KWORD[11],"ODD");
strcpy(KWORD[ 12],"PROCEDURE"); strcpy(KWORD[ 13],"PROGRAM");
strcpy(KWORD[14],"READ"); strcpy(KWORD[15],"REAL");
strcpy(KWORD[16],"THEN");
strcpy(KWORD[ 17],"TO"); strcpy(KWORD[18],"VAR");
strcpy(KWORD[19],"WHILE"); strcpy(KWORD[20],"WRITE");
WSYM[ 1]=BEGINSYM; WSYM[ 2]=CALLSYM;
WSYM[ 3]=CHARSYM; WSYM[ 4]=CONSTSYM;
WSYM[ 5]=DOSYM; WSYM[ 6]=DOWNTOSYM;
WSYM[ 7]=ELSESYM; WSYM[ 8]=ENDSYM;
WSYM[ 9]=FORSYM; WSYM[ 10]=IFSYM;
WSYM[ 11]=ODDSYM; WSYM[ 12]=PROCSYM;
WSYM[ 13]=PROGSYM; WSYM[14]=READSYM;
WSYM[15]=REALSYM; WSYM[16]=THENSYM;
WSYM[17]=TOSYM; WSYM[18]=VARSYM;
WSYM[19]=WHILESYM; WSYM[20]=WRITESYM;
SSYM['+']=PLUS; SSYM['-']=MINUS;
SSYM['*']=TIMES; SSYM['/']=SLASH;
SSYM['(']=LPAREN; SSYM[')']=RPAREN;
SSYM['=']=EQL; SSYM[',']=COMMA;
SSYM['.']=PERIOD;
SSYM[';']=SEMICOLON;
SSYM['[']=LSQUARE;
SSYM[']']=RSQUARE;
SSYM['~']=MIDD;
strcpy(MNEMONIC[LIT],"LIT"); strcpy(MNEMONIC[OPR],"OPR");
strcpy(MNEMONIC[LOD],"LOD"); strcpy(MNEMONIC[STO],"STO");
strcpy(MNEMONIC[CAL],"CAL"); strcpy(MNEMONIC[INI],"INI");
strcpy(MNEMONIC[JMP],"JMP"); strcpy(MNEMONIC[JPC],"JPC");
DECLBEGSYS=(int*)malloc(sizeof(int)*46);
STATBEGSYS=(int*)malloc(sizeof(int)*46);
FACBEGSYS =(int*)malloc(sizeof(int)*46);
for(int j=0; j<46; j++) {
DECLBEGSYS[j]=0; STATBEGSYS[j]=0; FACBEGSYS[j] =0;
}
DECLBEGSYS[CONSTSYM]=1;
DECLBEGSYS[VARSYM]=1;
DECLBEGSYS[PROCSYM]=1;
STATBEGSYS[BEGINSYM]=1;
STATBEGSYS[CALLSYM]=1;
STATBEGSYS[IFSYM]=1;
STATBEGSYS[WHILESYM]=1;
STATBEGSYS[WRITESYM]=1;
FACBEGSYS[IDENT] =1;
FACBEGSYS[NUMBER]=1;
FACBEGSYS[LPAREN]=1;
FACBEGSYS[PLPL]=1;
FACBEGSYS[MIMI]=1;
FACBEGSYS[CHARS]=1;
FACBEGSYS[REALS]=1;
if ((FIN=fopen((Form1->EditName->Text+".PL0").c_str(),"r"))!=0) {
FOUT=fopen((Form1->EditName->Text+".COD").c_str(),"w");
Form1->printfs("=== COMPILE PL0 ===");
fprintf(FOUT,"=== COMPILE PL0 ===\n");
ERR=0;
CC=0; CX=0; LL=0; CH=' '; GetSym();
if (SYM!=PROGSYM) Error(0);
else {
GetSym();
if (SYM!=IDENT) Error(0);
else {
GetSym();
if (SYM!=SEMICOLON) Error(5);
else GetSym();
}
}
Block(0,0,SymSetAdd(PERIOD,SymSetUnion(DECLBEGSYS,STATBEGSYS)));
if (SYM!=PERIOD) Error(9);
if (ERR==0) Interpret();
else {
Form1->printfs("ERROR IN PL/0 PROGRAM");
fprintf(FOUT,"ERROR IN PL/0 PROGRAM");
}
fprintf(FOUT,"\n"); fclose(FOUT);
}
}
//---------------------------------------------------------------------------
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