1 /*****************************************************************************/
5 /* Expression evaluation for the ca65 macroassembler */
9 /* (C) 1998-2009, Ullrich von Bassewitz */
10 /* Roemerstrasse 52 */
11 /* D-70794 Filderstadt */
12 /* EMail: uz@cc65.org */
15 /* This software is provided 'as-is', without any expressed or implied */
16 /* warranty. In no event will the authors be held liable for any damages */
17 /* arising from the use of this software. */
19 /* Permission is granted to anyone to use this software for any purpose, */
20 /* including commercial applications, and to alter it and redistribute it */
21 /* freely, subject to the following restrictions: */
23 /* 1. The origin of this software must not be misrepresented; you must not */
24 /* claim that you wrote the original software. If you use this software */
25 /* in a product, an acknowledgment in the product documentation would be */
26 /* appreciated but is not required. */
27 /* 2. Altered source versions must be plainly marked as such, and must not */
28 /* be misrepresented as being the original software. */
29 /* 3. This notice may not be removed or altered from any source */
32 /*****************************************************************************/
59 #include "studyexpr.h"
67 /*****************************************************************************/
69 /*****************************************************************************/
73 /* Since all expressions are first packed into expression trees, and each
74 * expression tree node is allocated on the heap, we add some type of special
75 * purpose memory allocation here: Instead of freeing the nodes, we save some
76 * number of freed nodes for later and remember them in a single linked list
77 * using the Left link.
79 #define MAX_FREE_NODES 64
80 static ExprNode* FreeExprNodes = 0;
81 static unsigned FreeNodeCount = 0;
85 /*****************************************************************************/
87 /*****************************************************************************/
91 static ExprNode* NewExprNode (unsigned Op)
92 /* Create a new expression node */
96 /* Do we have some nodes in the list already? */
98 /* Use first node from list */
100 FreeExprNodes = N->Left;
102 /* Allocate fresh memory */
103 N = xmalloc (sizeof (ExprNode));
106 N->Left = N->Right = 0;
114 static void FreeExprNode (ExprNode* E)
118 if (E->Op == EXPR_SYMBOL) {
119 /* Remove the symbol reference */
120 SymDelExprRef (E->V.Sym, E);
122 /* Place the symbol into the free nodes list if possible */
123 if (FreeNodeCount < MAX_FREE_NODES) {
124 /* Remember this node for later */
125 E->Left = FreeExprNodes;
128 /* Free the memory */
136 /*****************************************************************************/
138 /*****************************************************************************/
142 static ExprNode* Expr0 (void);
146 int IsByteRange (long Val)
147 /* Return true if this is a byte value */
149 return (Val & ~0xFFL) == 0;
154 int IsWordRange (long Val)
155 /* Return true if this is a word value */
157 return (Val & ~0xFFFFL) == 0;
162 int IsFarRange (long Val)
163 /* Return true if this is a far (24 bit) value */
165 return (Val & ~0xFFFFFFL) == 0;
170 static int IsEasyConst (const ExprNode* E, long* Val)
171 /* Do some light checking if the given node is a constant. Don't care if E is
172 * a complex expression. If E is a constant, return true and place its value
173 * into Val, provided that Val is not NULL.
176 /* Resolve symbols, follow symbol chains */
177 while (E->Op == EXPR_SYMBOL) {
178 E = SymResolve (E->V.Sym);
180 /* Could not resolve */
185 /* Symbols resolved, check for a literal */
186 if (E->Op == EXPR_LITERAL) {
193 /* Not found to be a const according to our tests */
199 static ExprNode* LoByte (ExprNode* Operand)
200 /* Return the low byte of the given expression */
205 /* Special handling for const expressions */
206 if (IsEasyConst (Operand, &Val)) {
208 Expr = GenLiteralExpr (Val & 0xFF);
210 /* Extract byte #0 */
211 Expr = NewExprNode (EXPR_BYTE0);
212 Expr->Left = Operand;
219 static ExprNode* HiByte (ExprNode* Operand)
220 /* Return the high byte of the given expression */
225 /* Special handling for const expressions */
226 if (IsEasyConst (Operand, &Val)) {
228 Expr = GenLiteralExpr ((Val >> 8) & 0xFF);
230 /* Extract byte #1 */
231 Expr = NewExprNode (EXPR_BYTE1);
232 Expr->Left = Operand;
239 static ExprNode* BankByte (ExprNode* Operand)
240 /* Return the bank byte of the given expression */
245 /* Special handling for const expressions */
246 if (IsEasyConst (Operand, &Val)) {
248 Expr = GenLiteralExpr ((Val >> 16) & 0xFF);
250 /* Extract byte #2 */
251 Expr = NewExprNode (EXPR_BYTE2);
252 Expr->Left = Operand;
259 static ExprNode* LoWord (ExprNode* Operand)
260 /* Return the low word of the given expression */
265 /* Special handling for const expressions */
266 if (IsEasyConst (Operand, &Val)) {
268 Expr = GenLiteralExpr (Val & 0xFFFF);
270 /* Extract word #0 */
271 Expr = NewExprNode (EXPR_WORD0);
272 Expr->Left = Operand;
279 static ExprNode* HiWord (ExprNode* Operand)
280 /* Return the high word of the given expression */
285 /* Special handling for const expressions */
286 if (IsEasyConst (Operand, &Val)) {
288 Expr = GenLiteralExpr ((Val >> 16) & 0xFFFF);
290 /* Extract word #1 */
291 Expr = NewExprNode (EXPR_WORD1);
292 Expr->Left = Operand;
299 static ExprNode* Symbol (SymEntry* S)
300 /* Reference a symbol and return an expression for it */
303 /* Some weird error happened before */
304 return GenLiteralExpr (0);
306 /* Mark the symbol as referenced */
308 /* If the symbol is a variable, return just its value, otherwise
309 * return a reference to the symbol.
312 return CloneExpr (GetSymExpr (S));
314 /* Create symbol node */
315 return GenSymExpr (S);
322 ExprNode* FuncBankByte (void)
323 /* Handle the .BANKBYTE builtin function */
325 return BankByte (Expression ());
330 static ExprNode* FuncBlank (void)
331 /* Handle the .BLANK builtin function */
333 /* We have a list of tokens that ends with the closing paren. Skip
334 * the tokens, and count them. Allow optionally curly braces.
336 Token Term = GetTokListTerm (TOK_RPAREN);
338 while (Tok != Term) {
340 /* Check for end of line or end of input. Since the calling function
341 * will check for the closing paren, we don't need to print an error
342 * here, just bail out.
344 if (TokIsSep (Tok)) {
355 /* If the list was enclosed in curly braces, skip the closing brace */
356 if (Term == TOK_RCURLY && Tok == TOK_RCURLY) {
360 /* Return true if the list was empty */
361 return GenLiteralExpr (Count == 0);
366 static ExprNode* FuncConst (void)
367 /* Handle the .CONST builtin function */
369 /* Read an expression */
370 ExprNode* Expr = Expression ();
372 /* Check the constness of the expression */
373 ExprNode* Result = GenLiteralExpr (IsConstExpr (Expr, 0));
375 /* Free the expression */
384 static ExprNode* FuncDefined (void)
385 /* Handle the .DEFINED builtin function */
387 /* Parse the symbol name and search for the symbol */
388 SymEntry* Sym = ParseScopedSymName (SYM_FIND_EXISTING);
390 /* Check if the symbol is defined */
391 return GenLiteralExpr (Sym != 0 && SymIsDef (Sym));
396 ExprNode* FuncHiByte (void)
397 /* Handle the .HIBYTE builtin function */
399 return HiByte (Expression ());
404 static ExprNode* FuncHiWord (void)
405 /* Handle the .HIWORD builtin function */
407 return HiWord (Expression ());
412 ExprNode* FuncLoByte (void)
413 /* Handle the .LOBYTE builtin function */
415 return LoByte (Expression ());
420 static ExprNode* FuncLoWord (void)
421 /* Handle the .LOWORD builtin function */
423 return LoWord (Expression ());
428 static ExprNode* DoMatch (enum TC EqualityLevel)
429 /* Handle the .MATCH and .XMATCH builtin functions */
436 /* A list of tokens follows. Read this list and remember it building a
437 * single linked list of tokens including attributes. The list is
438 * either enclosed in curly braces, or terminated by a comma.
440 Token Term = GetTokListTerm (TOK_COMMA);
441 while (Tok != Term) {
443 /* We may not end-of-line of end-of-file here */
444 if (TokIsSep (Tok)) {
445 Error ("Unexpected end of line");
446 return GenLiteral0 ();
449 /* Get a node with this token */
450 Node = NewTokNode ();
452 /* Insert the node into the list */
464 /* Skip the terminator token*/
467 /* If the token list was enclosed in curly braces, we expect a comma */
468 if (Term == TOK_RCURLY) {
472 /* Read the second list which is optionally enclosed in curly braces and
473 * terminated by the right parenthesis. Compare each token against the
474 * one in the first list.
476 Term = GetTokListTerm (TOK_RPAREN);
479 while (Tok != Term) {
481 /* We may not end-of-line of end-of-file here */
482 if (TokIsSep (Tok)) {
483 Error ("Unexpected end of line");
484 return GenLiteral0 ();
487 /* Compare the tokens if the result is not already known */
490 /* The second list is larger than the first one */
492 } else if (TokCmp (Node) < EqualityLevel) {
493 /* Tokens do not match */
498 /* Next token in first list */
503 /* Next token in current list */
507 /* If the token list was enclosed in curly braces, eat the closing brace */
508 if (Term == TOK_RCURLY) {
512 /* Check if there are remaining tokens in the first list */
517 /* Free the token list */
524 /* Done, return the result */
525 return GenLiteralExpr (Result);
530 static ExprNode* FuncMatch (void)
531 /* Handle the .MATCH function */
533 return DoMatch (tcSameToken);
538 static ExprNode* FuncReferenced (void)
539 /* Handle the .REFERENCED builtin function */
541 /* Parse the symbol name and search for the symbol */
542 SymEntry* Sym = ParseScopedSymName (SYM_FIND_EXISTING);
544 /* Check if the symbol is referenced */
545 return GenLiteralExpr (Sym != 0 && SymIsRef (Sym));
550 static ExprNode* FuncSizeOf (void)
551 /* Handle the .SIZEOF function */
553 StrBuf ScopeName = STATIC_STRBUF_INITIALIZER;
554 StrBuf Name = STATIC_STRBUF_INITIALIZER;
562 /* Assume an error */
565 /* Check for a cheap local which needs special handling */
566 if (Tok == TOK_LOCAL_IDENT) {
568 /* Cheap local symbol */
569 Sym = SymFindLocal (SymLast, &SVal, SYM_FIND_EXISTING);
571 Error ("Unknown symbol or scope: `%m%p'", &SVal);
573 SizeSym = GetSizeOfSymbol (Sym);
576 /* Remember and skip SVal, terminate ScopeName so it is empty */
577 SB_Copy (&Name, &SVal);
579 SB_Terminate (&ScopeName);
583 /* Parse the scope and the name */
584 SymTable* ParentScope = ParseScopedIdent (&Name, &ScopeName);
586 /* Check if the parent scope is valid */
587 if (ParentScope == 0) {
589 SB_Done (&ScopeName);
591 return GenLiteral0 ();
594 /* If ScopeName is empty, no explicit scope was specified. We have to
595 * search upper scope levels in this case.
597 NoScope = SB_IsEmpty (&ScopeName);
599 /* First search for a scope with the given name */
601 Scope = SymFindAnyScope (ParentScope, &Name);
603 Scope = SymFindScope (ParentScope, &Name, SYM_FIND_EXISTING);
606 /* If we did find a scope with the name, read the symbol defining the
607 * size, otherwise search for a symbol entry with the name and scope.
610 /* Yep, it's a scope */
611 SizeSym = GetSizeOfScope (Scope);
614 Sym = SymFindAny (ParentScope, &Name);
616 Sym = SymFind (ParentScope, &Name, SYM_FIND_EXISTING);
619 /* If we found the symbol retrieve the size, otherwise complain */
621 SizeSym = GetSizeOfSymbol (Sym);
623 Error ("Unknown symbol or scope: `%m%p%m%p'",
629 /* Check if we have a size */
630 if (SizeSym == 0 || !SymIsConst (SizeSym, &Size)) {
631 Error ("Size of `%m%p%m%p' is unknown", &ScopeName, &Name);
635 /* Free the string buffers */
636 SB_Done (&ScopeName);
639 /* Return the size */
640 return GenLiteralExpr (Size);
645 static ExprNode* FuncStrAt (void)
646 /* Handle the .STRAT function */
648 StrBuf Str = STATIC_STRBUF_INITIALIZER;
652 /* String constant expected */
653 if (Tok != TOK_STRCON) {
654 Error ("String constant expected");
659 /* Remember the string and skip it */
660 SB_Copy (&Str, &SVal);
663 /* Comma must follow */
666 /* Expression expected */
667 Index = ConstExpression ();
669 /* Must be a valid index */
670 if (Index >= (long) SB_GetLen (&Str)) {
671 Error ("Range error");
675 /* Get the char, handle as unsigned. Be sure to translate it into
676 * the target character set.
678 C = TgtTranslateChar (SB_At (&Str, (unsigned)Index));
681 /* Free string buffer memory */
684 /* Return the char expression */
685 return GenLiteralExpr (C);
690 static ExprNode* FuncStrLen (void)
691 /* Handle the .STRLEN function */
695 /* String constant expected */
696 if (Tok != TOK_STRCON) {
698 Error ("String constant expected");
699 /* Smart error recovery */
700 if (Tok != TOK_RPAREN) {
707 /* Get the length of the string */
708 Len = SB_GetLen (&SVal);
710 /* Skip the string */
714 /* Return the length */
715 return GenLiteralExpr (Len);
720 static ExprNode* FuncTCount (void)
721 /* Handle the .TCOUNT function */
723 /* We have a list of tokens that ends with the closing paren. Skip
724 * the tokens, and count them. Allow optionally curly braces.
726 Token Term = GetTokListTerm (TOK_RPAREN);
728 while (Tok != Term) {
730 /* Check for end of line or end of input. Since the calling function
731 * will check for the closing paren, we don't need to print an error
732 * here, just bail out.
734 if (TokIsSep (Tok)) {
745 /* If the list was enclosed in curly braces, skip the closing brace */
746 if (Term == TOK_RCURLY && Tok == TOK_RCURLY) {
750 /* Return the number of tokens */
751 return GenLiteralExpr (Count);
756 static ExprNode* FuncXMatch (void)
757 /* Handle the .XMATCH function */
759 return DoMatch (tcIdentical);
764 static ExprNode* Function (ExprNode* (*F) (void))
765 /* Handle builtin functions */
769 /* Skip the keyword */
772 /* Expression must be enclosed in braces */
773 if (Tok != TOK_LPAREN) {
774 Error ("'(' expected");
776 return GenLiteral0 ();
780 /* Call the function itself */
783 /* Closing brace must follow */
786 /* Return the result of the actual function */
792 static ExprNode* Factor (void)
801 N = GenLiteralExpr (IVal);
806 N = GenLiteralExpr (TgtTranslateChar (IVal));
812 N = Symbol (ParseScopedSymName (SYM_ALLOC_NEW));
815 case TOK_LOCAL_IDENT:
816 N = Symbol (SymFindLocal (SymLast, &SVal, SYM_ALLOC_NEW));
833 if (IsEasyConst (L, &Val)) {
835 N = GenLiteralExpr (-Val);
837 N = NewExprNode (EXPR_UNARY_MINUS);
845 if (IsEasyConst (L, &Val)) {
847 N = GenLiteralExpr (~Val);
849 N = NewExprNode (EXPR_NOT);
862 N = LoByte (Factor ());
867 N = HiByte (Factor ());
872 N = BankByte (Factor ());
882 N = Function (FuncBankByte);
886 N = Function (FuncBlank);
890 N = Function (FuncConst);
894 N = GenLiteralExpr (CPUIsets[CPU]);
899 N = Function (FuncDefined);
903 N = Function (FuncHiByte);
907 N = Function (FuncHiWord);
911 N = Function (FuncLoByte);
915 N = Function (FuncLoWord);
919 N = Function (FuncMatch);
923 N = Function (FuncReferenced);
927 N = Function (FuncSizeOf);
931 N = Function (FuncStrAt);
935 N = Function (FuncStrLen);
939 N = Function (FuncTCount);
943 N = GenLiteralExpr (time (0));
948 N = GenLiteralExpr (GetVersionAsNumber ());
953 N = Function (FuncXMatch);
957 if (LooseCharTerm && Tok == TOK_STRCON && SB_GetLen (&SVal) == 1) {
958 /* A character constant */
959 N = GenLiteralExpr (TgtTranslateChar (SB_At (&SVal, 0)));
961 N = GenLiteral0 (); /* Dummy */
962 Error ("Syntax error");
972 static ExprNode* Term (void)
974 /* Read left hand side */
975 ExprNode* Root = Factor ();
977 /* Handle multiplicative operations */
978 while (Tok == TOK_MUL || Tok == TOK_DIV || Tok == TOK_MOD ||
979 Tok == TOK_AND || Tok == TOK_XOR || Tok == TOK_SHL ||
982 long LVal, RVal, Val;
986 /* Remember the token and skip it */
990 /* Move root to left side and read the right side */
994 /* If both expressions are constant, we can evaluate the term */
995 if (IsEasyConst (Left, &LVal) && IsEasyConst (Right, &RVal)) {
1004 Error ("Division by zero");
1013 Error ("Modulo operation with zero");
1029 Val = shl_l (LVal, RVal);
1033 Val = shr_l (LVal, RVal);
1037 Internal ("Invalid token");
1040 /* Generate a literal expression and delete the old left and
1045 Root = GenLiteralExpr (Val);
1049 /* Generate an expression tree */
1052 case TOK_MUL: Op = EXPR_MUL; break;
1053 case TOK_DIV: Op = EXPR_DIV; break;
1054 case TOK_MOD: Op = EXPR_MOD; break;
1055 case TOK_AND: Op = EXPR_AND; break;
1056 case TOK_XOR: Op = EXPR_XOR; break;
1057 case TOK_SHL: Op = EXPR_SHL; break;
1058 case TOK_SHR: Op = EXPR_SHR; break;
1059 default: Internal ("Invalid token");
1061 Root = NewExprNode (Op);
1063 Root->Right = Right;
1069 /* Return the expression tree we've created */
1075 static ExprNode* SimpleExpr (void)
1077 /* Read left hand side */
1078 ExprNode* Root = Term ();
1080 /* Handle additive operations */
1081 while (Tok == TOK_PLUS || Tok == TOK_MINUS || Tok == TOK_OR) {
1083 long LVal, RVal, Val;
1087 /* Remember the token and skip it */
1091 /* Move root to left side and read the right side */
1095 /* If both expressions are constant, we can evaluate the term */
1096 if (IsEasyConst (Left, &LVal) && IsEasyConst (Right, &RVal)) {
1099 case TOK_PLUS: Val = LVal + RVal; break;
1100 case TOK_MINUS: Val = LVal - RVal; break;
1101 case TOK_OR: Val = LVal | RVal; break;
1102 default: Internal ("Invalid token");
1105 /* Generate a literal expression and delete the old left and
1110 Root = GenLiteralExpr (Val);
1114 /* Generate an expression tree */
1117 case TOK_PLUS: Op = EXPR_PLUS; break;
1118 case TOK_MINUS: Op = EXPR_MINUS; break;
1119 case TOK_OR: Op = EXPR_OR; break;
1120 default: Internal ("Invalid token");
1122 Root = NewExprNode (Op);
1124 Root->Right = Right;
1129 /* Return the expression tree we've created */
1135 static ExprNode* BoolExpr (void)
1136 /* Evaluate a boolean expression */
1138 /* Read left hand side */
1139 ExprNode* Root = SimpleExpr ();
1141 /* Handle booleans */
1142 while (Tok == TOK_EQ || Tok == TOK_NE || Tok == TOK_LT ||
1143 Tok == TOK_GT || Tok == TOK_LE || Tok == TOK_GE) {
1145 long LVal, RVal, Val;
1149 /* Remember the token and skip it */
1153 /* Move root to left side and read the right side */
1155 Right = SimpleExpr ();
1157 /* If both expressions are constant, we can evaluate the term */
1158 if (IsEasyConst (Left, &LVal) && IsEasyConst (Right, &RVal)) {
1161 case TOK_EQ: Val = (LVal == RVal); break;
1162 case TOK_NE: Val = (LVal != RVal); break;
1163 case TOK_LT: Val = (LVal < RVal); break;
1164 case TOK_GT: Val = (LVal > RVal); break;
1165 case TOK_LE: Val = (LVal <= RVal); break;
1166 case TOK_GE: Val = (LVal >= RVal); break;
1167 default: Internal ("Invalid token");
1170 /* Generate a literal expression and delete the old left and
1175 Root = GenLiteralExpr (Val);
1179 /* Generate an expression tree */
1182 case TOK_EQ: Op = EXPR_EQ; break;
1183 case TOK_NE: Op = EXPR_NE; break;
1184 case TOK_LT: Op = EXPR_LT; break;
1185 case TOK_GT: Op = EXPR_GT; break;
1186 case TOK_LE: Op = EXPR_LE; break;
1187 case TOK_GE: Op = EXPR_GE; break;
1188 default: Internal ("Invalid token");
1190 Root = NewExprNode (Op);
1192 Root->Right = Right;
1197 /* Return the expression tree we've created */
1203 static ExprNode* Expr2 (void)
1204 /* Boolean operators: AND and XOR */
1206 /* Read left hand side */
1207 ExprNode* Root = BoolExpr ();
1209 /* Handle booleans */
1210 while (Tok == TOK_BOOLAND || Tok == TOK_BOOLXOR) {
1212 long LVal, RVal, Val;
1216 /* Remember the token and skip it */
1220 /* Move root to left side and read the right side */
1222 Right = BoolExpr ();
1224 /* If both expressions are constant, we can evaluate the term */
1225 if (IsEasyConst (Left, &LVal) && IsEasyConst (Right, &RVal)) {
1228 case TOK_BOOLAND: Val = ((LVal != 0) && (RVal != 0)); break;
1229 case TOK_BOOLXOR: Val = ((LVal != 0) ^ (RVal != 0)); break;
1230 default: Internal ("Invalid token");
1233 /* Generate a literal expression and delete the old left and
1238 Root = GenLiteralExpr (Val);
1242 /* Generate an expression tree */
1245 case TOK_BOOLAND: Op = EXPR_BOOLAND; break;
1246 case TOK_BOOLXOR: Op = EXPR_BOOLXOR; break;
1247 default: Internal ("Invalid token");
1249 Root = NewExprNode (Op);
1251 Root->Right = Right;
1256 /* Return the expression tree we've created */
1262 static ExprNode* Expr1 (void)
1263 /* Boolean operators: OR */
1265 /* Read left hand side */
1266 ExprNode* Root = Expr2 ();
1268 /* Handle booleans */
1269 while (Tok == TOK_BOOLOR) {
1271 long LVal, RVal, Val;
1275 /* Remember the token and skip it */
1279 /* Move root to left side and read the right side */
1283 /* If both expressions are constant, we can evaluate the term */
1284 if (IsEasyConst (Left, &LVal) && IsEasyConst (Right, &RVal)) {
1287 case TOK_BOOLOR: Val = ((LVal != 0) || (RVal != 0)); break;
1288 default: Internal ("Invalid token");
1291 /* Generate a literal expression and delete the old left and
1296 Root = GenLiteralExpr (Val);
1300 /* Generate an expression tree */
1303 case TOK_BOOLOR: Op = EXPR_BOOLOR; break;
1304 default: Internal ("Invalid token");
1306 Root = NewExprNode (Op);
1308 Root->Right = Right;
1313 /* Return the expression tree we've created */
1319 static ExprNode* Expr0 (void)
1320 /* Boolean operators: NOT */
1324 /* Handle booleans */
1325 if (Tok == TOK_BOOLNOT) {
1330 /* Skip the operator token */
1333 /* Read the argument */
1336 /* If the argument is const, evaluate it directly */
1337 if (IsEasyConst (Left, &Val)) {
1339 Root = GenLiteralExpr (!Val);
1341 Root = NewExprNode (EXPR_BOOLNOT);
1347 /* Read left hand side */
1352 /* Return the expression tree we've created */
1358 ExprNode* Expression (void)
1359 /* Evaluate an expression, build the expression tree on the heap and return
1360 * a pointer to the root of the tree.
1368 long ConstExpression (void)
1369 /* Parse an expression. Check if the expression is const, and print an error
1370 * message if not. Return the value of the expression, or a dummy, if it is
1376 /* Read the expression */
1377 ExprNode* Expr = Expression ();
1379 /* Study the expression */
1382 StudyExpr (Expr, &D);
1384 /* Check if the expression is constant */
1385 if (ED_IsConst (&D)) {
1388 Error ("Constant expression expected");
1392 /* Free the expression tree and allocated memory for D */
1396 /* Return the value */
1402 void FreeExpr (ExprNode* Root)
1403 /* Free the expression, Root is pointing to. */
1406 FreeExpr (Root->Left);
1407 FreeExpr (Root->Right);
1408 FreeExprNode (Root);
1414 ExprNode* SimplifyExpr (ExprNode* Expr, const ExprDesc* D)
1415 /* Try to simplify the given expression tree */
1417 if (Expr->Op != EXPR_LITERAL && ED_IsConst (D)) {
1418 /* No external references */
1420 Expr = GenLiteralExpr (D->Val);
1427 ExprNode* GenLiteralExpr (long Val)
1428 /* Return an expression tree that encodes the given literal value */
1430 ExprNode* Expr = NewExprNode (EXPR_LITERAL);
1437 ExprNode* GenLiteral0 (void)
1438 /* Return an expression tree that encodes the the number zero */
1440 return GenLiteralExpr (0);
1445 ExprNode* GenSymExpr (SymEntry* Sym)
1446 /* Return an expression node that encodes the given symbol */
1448 ExprNode* Expr = NewExprNode (EXPR_SYMBOL);
1450 SymAddExprRef (Sym, Expr);
1456 static ExprNode* GenSectionExpr (unsigned SegNum)
1457 /* Return an expression node for the given section */
1459 ExprNode* Expr = NewExprNode (EXPR_SECTION);
1460 Expr->V.SegNum = SegNum;
1466 ExprNode* GenAddExpr (ExprNode* Left, ExprNode* Right)
1467 /* Generate an addition from the two operands */
1470 if (IsEasyConst (Left, &Val) && Val == 0) {
1473 } else if (IsEasyConst (Right, &Val) && Val == 0) {
1477 ExprNode* Root = NewExprNode (EXPR_PLUS);
1479 Root->Right = Right;
1486 ExprNode* GenCurrentPC (void)
1487 /* Return the current program counter as expression */
1491 if (GetRelocMode ()) {
1492 /* Create SegmentBase + Offset */
1493 Root = GenAddExpr (GenSectionExpr (GetCurrentSegNum ()),
1494 GenLiteralExpr (GetPC ()));
1496 /* Absolute mode, just return PC value */
1497 Root = GenLiteralExpr (GetPC ());
1505 ExprNode* GenSwapExpr (ExprNode* Expr)
1506 /* Return an extended expression with lo and hi bytes swapped */
1508 ExprNode* N = NewExprNode (EXPR_SWAP);
1515 ExprNode* GenBranchExpr (unsigned Offs)
1516 /* Return an expression that encodes the difference between current PC plus
1517 * offset and the target expression (that is, Expression() - (*+Offs) ).
1524 /* Read Expression() */
1527 /* If the expression is a cheap constant, generate a simpler tree */
1528 if (IsEasyConst (N, &Val)) {
1530 /* Free the constant expression tree */
1533 /* Generate the final expression:
1535 * Val - ((Seg + PC) + Offs)
1536 * Val - Seg - PC - Offs
1537 * (Val - PC - Offs) - Seg
1539 Root = GenLiteralExpr (Val - GetPC () - Offs);
1540 if (GetRelocMode ()) {
1542 Root = NewExprNode (EXPR_MINUS);
1544 Root->Right = GenSectionExpr (GetCurrentSegNum ());
1549 /* Generate the expression:
1551 * N - ((Seg + PC) + Offs)
1552 * N - Seg - PC - Offs
1553 * N - (PC + Offs) - Seg
1555 Root = NewExprNode (EXPR_MINUS);
1557 Root->Right = GenLiteralExpr (GetPC () + Offs);
1558 if (GetRelocMode ()) {
1560 Root = NewExprNode (EXPR_MINUS);
1562 Root->Right = GenSectionExpr (GetCurrentSegNum ());
1566 /* Return the result */
1572 ExprNode* GenULabelExpr (unsigned Num)
1573 /* Return an expression for an unnamed label with the given index */
1575 ExprNode* Node = NewExprNode (EXPR_ULABEL);
1578 /* Return the new node */
1584 ExprNode* GenByteExpr (ExprNode* Expr)
1585 /* Force the given expression into a byte and return the result */
1587 /* Use the low byte operator to force the expression into byte size */
1588 return LoByte (Expr);
1593 ExprNode* GenWordExpr (ExprNode* Expr)
1594 /* Force the given expression into a word and return the result. */
1596 /* Use the low byte operator to force the expression into word size */
1597 return LoWord (Expr);
1602 ExprNode* GenNE (ExprNode* Expr, long Val)
1603 /* Generate an expression that compares Expr and Val for inequality */
1605 /* Generate a compare node */
1606 ExprNode* Root = NewExprNode (EXPR_NE);
1608 Root->Right = GenLiteralExpr (Val);
1610 /* Return the result */
1616 int IsConstExpr (ExprNode* Expr, long* Val)
1617 /* Return true if the given expression is a constant expression, that is, one
1618 * with no references to external symbols. If Val is not NULL and the
1619 * expression is constant, the constant value is stored here.
1624 /* Study the expression */
1627 StudyExpr (Expr, &D);
1629 /* Check if the expression is constant */
1630 IsConst = ED_IsConst (&D);
1631 if (IsConst && Val != 0) {
1635 /* Delete allocated memory and return the result */
1642 ExprNode* CloneExpr (ExprNode* Expr)
1643 /* Clone the given expression tree. The function will simply clone symbol
1644 * nodes, it will not resolve them.
1649 /* Accept NULL pointers */
1654 /* Clone the node */
1658 Clone = GenLiteralExpr (Expr->V.IVal);
1662 Clone = GenULabelExpr (Expr->V.IVal);
1666 Clone = GenSymExpr (Expr->V.Sym);
1670 Clone = GenSectionExpr (Expr->V.SegNum);
1674 /* Generate a new node */
1675 Clone = NewExprNode (Expr->Op);
1676 /* Clone the tree nodes */
1677 Clone->Left = CloneExpr (Expr->Left);
1678 Clone->Right = CloneExpr (Expr->Right);
1688 void WriteExpr (ExprNode* Expr)
1689 /* Write the given expression to the object file */
1691 /* Null expressions are encoded by a type byte of zero */
1693 ObjWrite8 (EXPR_NULL);
1697 /* If the is a leafnode, write the expression attribute, otherwise
1698 * write the expression operands.
1703 ObjWrite8 (EXPR_LITERAL);
1704 ObjWrite32 (Expr->V.IVal);
1708 if (SymIsImport (Expr->V.Sym)) {
1709 ObjWrite8 (EXPR_SYMBOL);
1710 ObjWriteVar (GetSymIndex (Expr->V.Sym));
1712 WriteExpr (GetSymExpr (Expr->V.Sym));
1717 ObjWrite8 (EXPR_SECTION);
1718 ObjWrite8 (Expr->V.SegNum);
1722 WriteExpr (ULabResolve (Expr->V.IVal));
1726 /* Not a leaf node */
1727 ObjWrite8 (Expr->Op);
1728 WriteExpr (Expr->Left);
1729 WriteExpr (Expr->Right);
1737 void ExprGuessedAddrSize (const ExprNode* Expr, unsigned char AddrSize)
1738 /* Mark the address size of the given expression tree as guessed. The address
1739 * size passed as argument is the one NOT used, because the actual address
1740 * size wasn't known. Example: Zero page addressing was not used because symbol
1741 * is undefined, and absolute addressing was available.
1742 * This function will actually parse the expression tree for undefined symbols,
1743 * and mark these symbols accordingly.
1746 /* Accept NULL expressions */
1751 /* Check the type code */
1752 switch (Expr->Op & EXPR_TYPEMASK) {
1755 if (Expr->Op == EXPR_SYMBOL) {
1756 if (!SymIsDef (Expr->V.Sym)) {
1757 /* Symbol is undefined, mark it */
1758 SymGuessedAddrSize (Expr->V.Sym, AddrSize);
1763 case EXPR_BINARYNODE:
1764 ExprGuessedAddrSize (Expr->Right, AddrSize);
1767 case EXPR_UNARYNODE:
1768 ExprGuessedAddrSize (Expr->Left, AddrSize);