📄 unit1.cpp
字号:
switch (K) {
case CONSTANT:
if (NUM>AMAX) { Error(31); NUM=0; }
TABLE[TX].VAL=NUM;
break;
case VARIABLE:
TABLE[TX].vp.LEVEL=LEV; TABLE[TX].vp.ADR=DX; DX++;
break;
case PROCEDUR:
TABLE[TX].vp.LEVEL=LEV;
break;
}
} /*ENTER*/
//---------------------------------------------------------------------------
int POSITION(ALFA ID, int TX) { /*FIND IDENTIFIER IN TABLE*/
int i=TX;
strcpy(TABLE[0].NAME,ID);
while (strcmp(TABLE[i].NAME,ID)!=0) i--;
return i;
} /*POSITION*/
//---------------------------------------------------------------------------
void ConstDeclaration(int LEV,int &TX,int &DX) {
if (SYM==IDENT) {
GetSym();
if (SYM==EQL||SYM==BECOMES) {
if (SYM==BECOMES) Error(1);
GetSym();
if (SYM==NUMBER) { ENTER(CONSTANT,LEV,TX,DX); GetSym(); }
else Error(2);
}
else Error(3);
}
else Error(4);
} /*ConstDeclaration()*/
//---------------------------------------------------------------------------
void VarDeclaration(int LEV,int &TX,int &DX) {
if (SYM==IDENT) { ENTER(VARIABLE,LEV,TX,DX); GetSym(); }
else Error(4);
} /*VarDeclaration()*/
//---------------------------------------------------------------------------
void ListCode(int CX0) { /*LIST CODE GENERATED FOR THIS Block*/
if (Form1->ListSwitch->ItemIndex==0)
for (int i=CX0; i<CX; i++) {
String s=IntToStr(i);
while(s.Length()<3)s=" "+s;
s=s+" "+MNEMONIC[CODE[i].F]+" "+IntToStr(CODE[i].L)+" "+IntToStr(CODE[i].A);
Form1->printfs(s.c_str());
fprintf(FOUT,"%3d%5s%4d%4d\n",i,MNEMONIC[CODE[i].F],CODE[i].L,CODE[i].A);
}
} /*ListCode()*/;
//---------------------------------------------------------------------------
void FACTOR(SYMSET FSYS, int LEV, int &TX) {
int i;
SYMBOL ADDOP;
TEST(FACBEGSYS,FSYS,24);
while (SymIn(SYM,FACBEGSYS)) {
if(SYM==INCREMENT||SYM==DECREMENT) //处理表达式中的++X,--X
{
ADDOP=SYM;
GetSym();
if(SYM==IDENT)
{
i=POSITION(ID,TX);
if (i==0) Error(11);
else
if (TABLE[i].KIND!=VARIABLE) { /*ASSIGNMENT TO NON-VARIABLE*/
Error(37); i=0;
}
else
{
GEN(LOD,LEV-TABLE[i].vp.LEVEL,TABLE[i].vp.ADR);
GEN(LIT,0,1);
if(ADDOP==INCREMENT) GEN(OPR,0,2);
else GEN(OPR,0,3);
GEN(STO,LEV-TABLE[i].vp.LEVEL,TABLE[i].vp.ADR);
GEN(LOD,LEV-TABLE[i].vp.LEVEL,TABLE[i].vp.ADR);
GetSym();
}
}
}
else if (SYM==IDENT) {
i=POSITION(ID,TX);
if (i==0) Error(11);
else
switch (TABLE[i].KIND) {
case CONSTANT: GEN(LIT,0,TABLE[i].VAL); GetSym();break;
case VARIABLE:
GEN(LOD,LEV-TABLE[i].vp.LEVEL,TABLE[i].vp.ADR);
GetSym();
if(SYM==INCREMENT||SYM==DECREMENT) //处理表达式中的X++,X--
{
GEN(LOD,LEV-TABLE[i].vp.LEVEL,TABLE[i].vp.ADR);
GEN(LIT,0,1);
if(SYM==INCREMENT) GEN(OPR,0,2);
else GEN(OPR,0,3);
GEN(STO,LEV-TABLE[i].vp.LEVEL,TABLE[i].vp.ADR);
GetSym();
}
break;
case PROCEDUR: Error(21); break;
}
}
else
if (SYM==NUMBER) {
if (NUM>AMAX) { Error(31); NUM=0; }
GEN(LIT,0,NUM); GetSym();
}
else
if (SYM==LPAREN) {
GetSym(); EXPRESSION(SymSetAdd(RPAREN,FSYS),LEV,TX);
if (SYM==RPAREN) GetSym();
else Error(22);
}
TEST(FSYS,FACBEGSYS,23);
}
}/*FACTOR*/
//---------------------------------------------------------------------------
void TERM(SYMSET FSYS, int LEV, int &TX) { /*TERM*/
SYMBOL MULOP;
FACTOR(SymSetUnion(FSYS,SymSetNew(TIMES,SLASH)), LEV,TX);
while (SYM==TIMES || SYM==SLASH) {
MULOP=SYM; GetSym();
FACTOR(SymSetUnion(FSYS,SymSetNew(TIMES,SLASH)),LEV,TX);
if (MULOP==TIMES) GEN(OPR,0,4);
else GEN(OPR,0,5);
}
} /*TERM*/;
//---------------------------------------------------------------------------
void EXPRESSION(SYMSET FSYS, int LEV, int &TX) {
SYMBOL ADDOP;
if (SYM==PLUS || SYM==MINUS) {
ADDOP=SYM; GetSym();
TERM(SymSetUnion(FSYS,SymSetNew(PLUS,MINUS)),LEV,TX);
if (ADDOP==MINUS) GEN(OPR,0,1);
}
else TERM(SymSetUnion(FSYS,SymSetNew(PLUS,MINUS)),LEV,TX);
while (SYM==PLUS || SYM==MINUS) {
ADDOP=SYM; GetSym();
TERM(SymSetUnion(FSYS,SymSetNew(PLUS,MINUS)),LEV,TX);
if (ADDOP==PLUS) GEN(OPR,0,2);
else GEN(OPR,0,3);
}
} /*EXPRESSION*/
//---------------------------------------------------------------------------
void CONDITION(SYMSET FSYS,int LEV,int &TX) {
SYMBOL RELOP;
if (SYM==ODDSYM) { GetSym(); EXPRESSION(FSYS,LEV,TX); GEN(OPR,0,6); }
else {
EXPRESSION(SymSetUnion(SymSetNew(EQL,NEQ,LSS,LEQ,GTR,GEQ),FSYS),LEV,TX);
if (!SymIn(SYM,SymSetNew(EQL,NEQ,LSS,LEQ,GTR,GEQ))) Error(20);
else {
RELOP=SYM; GetSym(); EXPRESSION(FSYS,LEV,TX);
switch (RELOP) {
case EQL: GEN(OPR,0,8); break;
case NEQ: GEN(OPR,0,9); break;
case LSS: GEN(OPR,0,10); break;
case GEQ: GEN(OPR,0,11); break;
case GTR: GEN(OPR,0,12); break;
case LEQ: GEN(OPR,0,13); break;
}
}
}
} /*CONDITION*/
//---------------------------------------------------------------------------
void STATEMENT(SYMSET FSYS,int LEV,int &TX) { /*STATEMENT*/
int i,CX1,CX2;
SYMBOL ADDOP;
switch (SYM) {
case IDENT:
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(FSYS,LEV,TX);
if (i!=0) GEN(STO,LEV-TABLE[i].vp.LEVEL,TABLE[i].vp.ADR);
}
else if(SYM==ADDEQL||SYM==SUBEQL) //处理+=及-=
{
ADDOP=SYM;
if(i!=0)
{
GetSym();
GEN(LOD,LEV-TABLE[i].vp.LEVEL,TABLE[i].vp.ADR);
EXPRESSION(FSYS,LEV,TX);
if(ADDOP==ADDEQL) GEN(OPR,0,2);
else GEN(OPR,0,3);
GEN(STO,LEV-TABLE[i].vp.LEVEL,TABLE[i].vp.ADR);
}
}
else if(SYM==INCREMENT||SYM==DECREMENT) //处理X++及X--
{
ADDOP=SYM;
GetSym();
if(i!=0)
{
GEN(LOD,LEV-TABLE[i].vp.LEVEL,TABLE[i].vp.ADR);
GEN(LIT,0,1);
if(ADDOP==INCREMENT) GEN(OPR,0,2);
else GEN(OPR,0,3);
GEN(STO,LEV-TABLE[i].vp.LEVEL,TABLE[i].vp.ADR);
}
}
else Error(13);
break;
case INCREMENT: //处理++X
GetSym();
if(SYM==IDENT)
{
i=POSITION(ID,TX);
if (i==0) Error(11);
else
if (TABLE[i].KIND!=VARIABLE) { /*ASSIGNMENT TO NON-VARIABLE*/
Error(12); i=0;
}
else
{
GetSym();
if(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);
}
}
}
else Error(8);
break;
case DECREMENT: //处理--X
GetSym();
if(SYM==IDENT)
{
i=POSITION(ID,TX);
if (i==0) Error(11);
else
if (TABLE[i].KIND!=VARIABLE) { /*ASSIGNMENT TO NON-VARIABLE*/
Error(12); i=0;
}
else
{
GetSym();
if(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);
}
}
}
else Error(8);
break;
case READSYM:
GetSym();
if (SYM!=LPAREN) Error(34);
else
do {
GetSym();
if (SYM==IDENT) i=POSITION(ID,TX);
else i=0;
if (i==0) Error(35);
else {
GEN(OPR,0,16);
GEN(STO,LEV-TABLE[i].vp.LEVEL,TABLE[i].vp.ADR);
}
GetSym();
}while(SYM==COMMA);
if (SYM!=RPAREN) {
Error(33);
while (!SymIn(SYM,FSYS)) GetSym();
}
else GetSym();
break; /* READSYM */
case WRITESYM:
GetSym();
if (SYM==LPAREN) {
do {
GetSym();
EXPRESSION(SymSetUnion(SymSetNew(RPAREN,COMMA),FSYS),LEV,TX);
GEN(OPR,0,14);
}while(SYM==COMMA);
if (SYM!=RPAREN) Error(33);
else GetSym();
}
GEN(OPR,0,15);
break; /*WRITESYM*/
case CALLSYM:
GetSym();
if (SYM!=IDENT) Error(14);
else {
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