Fail when using negative constants if not allowed

Some commands, such as `DS`, `BANK[n]`, etc, don't allow the use of
negative constants, but there wasn't any check to prohibit the code from
trying to do so.

This patch adds the `uconst` type to the parser to use when a constant
is expected, but it mustn't be negative.

Signed-off-by: Antonio Niño Díaz <antonio_nd@outlook.com>

src/asm/asmy.y

@@ -439,6 +439,7 @@ void	if_skip_to_endc( void )
 
 %type	<sVal>	relocconst
 %type	<nConstValue>	const
+%type	<nConstValue>	uconst
 %type	<nConstValue>	const_3bit
 %type	<sVal>	const_8bit
 %type	<sVal>	const_16bit
@@ -587,7 +588,11 @@ label : /* empty */
 		else
 			sym_AddReloc($1);
 	} | T_LABEL ':' ':' {
+		if ($1[0] == '.') {
+			sym_AddLocalReloc($1);
+		} else {
 			sym_AddReloc($1);
+		}
 		sym_Export($1);
 	};
 
@@ -688,7 +693,7 @@ shift			:	T_POP_SHIFT
 					{ sym_ShiftCurrentMacroArgs(); }
 ;
 
-rept			:	T_POP_REPT const
+rept			:	T_POP_REPT uconst
 					{
 						copyrept();
 						fstk_RunRept( $2 );
@@ -706,7 +711,7 @@ equs			:	T_LABEL T_POP_EQUS string
 					{ sym_AddString( $1, $3 ); }
 ;
 
-rsset			:	T_POP_RSSET const
+rsset			:	T_POP_RSSET uconst
 					{ sym_AddSet( "_RS", $2 ); }
 ;
 
@@ -714,28 +719,28 @@ rsreset			:	T_POP_RSRESET
 					{ sym_AddSet( "_RS", 0 ); }
 ;
 
-rl				:	T_LABEL T_POP_RL const
+rl				:	T_LABEL T_POP_RL uconst
 					{
 						sym_AddEqu( $1, sym_GetConstantValue("_RS") );
 						sym_AddSet( "_RS", sym_GetConstantValue("_RS")+4*$3 );
 					}
 ;
 
-rw				:	T_LABEL T_POP_RW const
+rw				:	T_LABEL T_POP_RW uconst
 					{
 						sym_AddEqu( $1, sym_GetConstantValue("_RS") );
 						sym_AddSet( "_RS", sym_GetConstantValue("_RS")+2*$3 );
 					}
 ;
 
-rb				:	T_LABEL T_POP_RB const
+rb				:	T_LABEL T_POP_RB uconst
 					{
 						sym_AddEqu( $1, sym_GetConstantValue("_RS") );
 						sym_AddSet( "_RS", sym_GetConstantValue("_RS")+$3 );
 					}
 ;
 
-ds				:	T_POP_DS const
+ds				:	T_POP_DS uconst
 					{ out_Skip( $2 ); }
 ;
 
@@ -817,7 +822,7 @@ include			:	T_POP_INCLUDE string
 
 incbin			:	T_POP_INCBIN string
 					{ out_BinaryFile( $2 ); }
-				|	T_POP_INCBIN string ',' const ',' const
+				|	T_POP_INCBIN string ',' uconst ',' uconst
 					{
 						out_BinaryFileSlice( $2, $4, $6 );
 					}
@@ -1038,6 +1043,14 @@ relocconst		:	T_ID
 						{ $$ = $2; }
 ;
 
+uconst			:	const
+					{
+						if($1 < 0)
+							fatalerror("Constant mustn't be negative: %d", $1);
+						$$=$1;
+					}
+;
+
 const			:	T_ID							{ $$ = sym_GetConstantValue($1); }
 				|	T_NUMBER 						{ $$ = $1; }
 				|	string						{ $$ = str2int($1); }
@@ -1064,12 +1077,14 @@ const			:	T_ID							{ $$ = sym_GetConstantValue($1); }
 				|	const T_OP_SHL const			{ $$ = $1 << $3; }
 				|	const T_OP_SHR const			{ $$ = $1 >> $3; }
 				|	const T_OP_MUL const			{ $$ = $1 * $3; }
-				|	const T_OP_DIV const			{
+				|	const T_OP_DIV const
+					{
 						if ($3 == 0)
 							fatalerror("division by zero");
 						$$ = $1 / $3;
 					}
-				|	const T_OP_MOD const			{
+				|	const T_OP_MOD const
+					{
 						if ($3 == 0)
 							fatalerror("division by zero");
 						$$ = $1 % $3;
@@ -1109,7 +1124,7 @@ const			:	T_ID							{ $$ = sym_GetConstantValue($1); }
 
 string			:	T_STRING
 					{ strcpy($$,$1); }
-				|	T_OP_STRSUB '(' string ',' const ',' const ')'
+				|	T_OP_STRSUB '(' string ',' uconst ',' uconst ')'
 					{ strncpy($$,$3+$5-1,$7); $$[$7]=0; }
 				|	T_OP_STRCAT '(' string ',' string ')'
 					{ strcpy($$,$3); strcat($$,$5); }
@@ -1123,33 +1138,33 @@ section:
 		{
 			out_NewSection($2,$4);
 		}
-	|	T_POP_SECTION string ',' sectiontype '[' const ']'
+	|	T_POP_SECTION string ',' sectiontype '[' uconst ']'
 		{
 			if( $6>=0 && $6<0x10000 )
 				out_NewAbsSection($2,$4,$6,-1);
 			else
 				yyerror("Address $%x not 16-bit", $6);
 		}
-	|	T_POP_SECTION string ',' sectiontype ',' T_OP_ALIGN '[' const ']'
+	|	T_POP_SECTION string ',' sectiontype ',' T_OP_ALIGN '[' uconst ']'
 		{
 			out_NewAlignedSection($2, $4, $8, -1);
 		}
-	|	T_POP_SECTION string ',' sectiontype ',' T_OP_BANK '[' const ']'
+	|	T_POP_SECTION string ',' sectiontype ',' T_OP_BANK '[' uconst ']'
 		{
 			bankrangecheck($2, $4, -1, $8);
 		}
-	|	T_POP_SECTION string ',' sectiontype '[' const ']' ',' T_OP_BANK '[' const ']'
+	|	T_POP_SECTION string ',' sectiontype '[' uconst ']' ',' T_OP_BANK '[' uconst ']'
 		{
 			if ($6 < 0 || $6 > 0x10000) {
 				yyerror("Address $%x not 16-bit", $6);
 			}
 			bankrangecheck($2, $4, $6, $11);
 		}
-	|	T_POP_SECTION string ',' sectiontype ',' T_OP_ALIGN '[' const ']' ',' T_OP_BANK '[' const ']'
+	|	T_POP_SECTION string ',' sectiontype ',' T_OP_ALIGN '[' uconst ']' ',' T_OP_BANK '[' uconst ']'
 		{
 			out_NewAlignedSection($2, $4, $8, $13);
 		}
-	|	T_POP_SECTION string ',' sectiontype ',' T_OP_BANK '[' const ']' ',' T_OP_ALIGN '[' const ']'
+	|	T_POP_SECTION string ',' sectiontype ',' T_OP_BANK '[' uconst ']' ',' T_OP_ALIGN '[' uconst ']'
 		{
 			out_NewAlignedSection($2, $4, $13, $8);
 		}

src/asm/globlex.c

@@ -475,6 +475,7 @@ setuplex(void)
 	lex_FloatAddSecondRange(id, '\\', '\\');
 	lex_FloatAddSecondRange(id, '@', '@');
 	lex_FloatAddSecondRange(id, '#', '#');
+	lex_FloatAddRange(id, '.', '.');
 	lex_FloatAddRange(id, 'a', 'z');
 	lex_FloatAddRange(id, 'A', 'Z');
 	lex_FloatAddRange(id, '0', '9');

src/asm/output.c

@@ -260,10 +260,6 @@ writesymbol(struct sSymbol * pSym, FILE * f)
 		sectid = -1;
 		type = SYM_IMPORT;
 	} else {
-		if (pSym->nType & SYMF_LOCAL) {
-			strcpy(symname, pSym->pScope->tzName);
-			strcat(symname, pSym->tzName);
-		} else
 		strcpy(symname, pSym->tzName);
 
 		if (pSym->nType & SYMF_EXPORT) {

src/asm/rgbasm.5

@@ -223,13 +223,17 @@ GlobalLabel
 AnotherGlobal:
 \&.locallabel
 \&.yet_a_local:
+AnotherGlobal.with_another_local:
 ThisWillBeExported:: ;note the two colons
+ThisWillBeExported.too::
 .Ed
 .Pp
 In the line where a label is defined there musn't be any whitespace before it.
 Local labels are only accessible within the scope they are defined.
 A scope starts after a global label and ends at the next global label.
-Declaring a normal label with :: does an EXPORT at the same time.
+Declaring a label (global or local) with :: does an EXPORT at the same time.
+Local labels can be declared as scope.local or simply as as .local.
+If the former notation is used, the scope must be the actual current scope.
 .Pp
 Labels will normally change their value during the link process and are thus not
 constant.
@@ -303,6 +307,8 @@ There are four commands in the RS group of commands:
 .Ic _RS No and adds Ar constexpr No to Ic _RS .
 .It Ic RW Ar constexpr Ta Sets the preceding symbol to
 .Ic _RS No and adds Ar constexpr No * 2 to Ic _RS.
+.It Ic RL Ar constexpr Ta Sets the preceding symbol to
+.Ic _RS No and adds Ar constexpr No * 4 to Ic _RS.
 .El
 .Pp
 Note that a colon (:) following the symbol-name is not allowed.
@@ -992,6 +998,7 @@ machine.
 .It Sx PUSHS
 .It Sx REPT
 .It Sx RB
+.It Sx RL
 .It Sx ROM0
 .It Sx ROMX
 .It Sx RSRESET

src/asm/symbol.c

@@ -114,26 +114,16 @@ createsymbol(char *s)
 		return (NULL);
 	}
 }
+
 /*
- * Find a symbol by name and scope
+ * Creates the full name of a local symbol in a given scope, by prepending
+ * the name with the parent symbol's name.
  */
-struct sSymbol *
+size_t
-findsymbol(char *s, struct sSymbol * scope)
+fullSymbolName(char *output, size_t outputSize, char *localName, struct sSymbol *scope)
 {
-	struct sSymbol **ppsym;
+	struct sSymbol *parent = scope->pScope ? scope->pScope : scope;
-	SLONG hash;
+	return snprintf(output, outputSize, "%s%s", parent->tzName, localName);
-
-	hash = calchash(s);
-	ppsym = &(tHashedSymbols[hash]);
-
-	while ((*ppsym) != NULL) {
-		if ((strcmp(s, (*ppsym)->tzName) == 0)
-		    && ((*ppsym)->pScope == scope)) {
-			return (*ppsym);
-		} else
-			ppsym = &((*ppsym)->pNext);
-	}
-	return (NULL);
 }
 
 /*
@@ -144,13 +134,25 @@ findpsymbol(char *s, struct sSymbol * scope)
 {
 	struct sSymbol **ppsym;
 	SLONG hash;
+	char fullname[MAXSYMLEN + 1];
+		
+	if (s[0] == '.' && scope) {
+		fullSymbolName(fullname, sizeof(fullname), s, scope);
+		s = fullname;
+	}
+	
+	char *seperator;
+	if ((seperator = strchr(s, '.'))) {
+		if (strchr(seperator + 1, '.')) {
+			fatalerror("'%s' is a nonsensical reference to a nested local symbol", s);
+		}
+	}
 
 	hash = calchash(s);
 	ppsym = &(tHashedSymbols[hash]);
 
 	while ((*ppsym) != NULL) {
-		if ((strcmp(s, (*ppsym)->tzName) == 0)
+		if ((strcmp(s, (*ppsym)->tzName) == 0)) {
-		    && ((*ppsym)->pScope == scope)) {
 			return (ppsym);
 		} else
 			ppsym = &((*ppsym)->pNext);
@@ -158,6 +160,16 @@ findpsymbol(char *s, struct sSymbol * scope)
 	return (NULL);
 }
 
+/*
+ * Find a symbol by name and scope
+ */
+struct sSymbol *
+findsymbol(char *s, struct sSymbol * scope)
+{
+	struct sSymbol **ppsym = findpsymbol(s, scope);
+	return ppsym ? *ppsym : NULL;
+}
+
 /*
  * Find a symbol by name and scope
  */
@@ -593,30 +605,16 @@ sym_AddSet(char *tzSym, SLONG value)
 void
 sym_AddLocalReloc(char *tzSym)
 {
-	if ((nPass == 1)
-	    || ((nPass == 2) && (sym_isDefined(tzSym) == 0))) {
-		/* only add local reloc symbols in pass 1 */
-		struct sSymbol *nsym;
-
 	if (pScope) {
-			if ((nsym = findsymbol(tzSym, pScope)) != NULL) {
+		if (strlen(tzSym) + strlen(pScope->tzName) > MAXSYMLEN) {
-				if (nsym->nType & SYMF_DEFINED) {
+			fatalerror("Symbol too long");
-					yyerror("'%s' already defined", tzSym);
 		}
-			} else
-				nsym = createsymbol(tzSym);
 		
-			if (nsym) {
+		char fullname[MAXSYMLEN + 1];
-				nsym->nValue = nPC;
+		fullSymbolName(fullname, sizeof(fullname), tzSym, pScope);
-				nsym->nType |=
+		sym_AddReloc(fullname);
-				    SYMF_RELOC | SYMF_LOCAL | SYMF_DEFINED;
+		
-				if (exportall) {
+	} else {
-				   nsym->nType |= SYMF_EXPORT;
-				}
-				nsym->pScope = pScope;
-				nsym->pSection = pCurrentSection;
-			}
-		} else
 		fatalerror("Local label in main scope");
 	}
 }
@@ -627,12 +625,32 @@ sym_AddLocalReloc(char *tzSym)
 void
 sym_AddReloc(char *tzSym)
 {
+	struct sSymbol* scope = NULL;
+	
 	if ((nPass == 1)
 	    || ((nPass == 2) && (sym_isDefined(tzSym) == 0))) {
 		/* only add reloc symbols in pass 1 */
 		struct sSymbol *nsym;
+		char *localPtr = NULL;
 		
-		if ((nsym = findsymbol(tzSym, NULL)) != NULL) {
+		if ((localPtr = strchr(tzSym, '.')) != NULL) {			
+			if (!pScope) {
+				fatalerror("Local label in main scope");
+			}
+			
+			struct sSymbol *parent = pScope->pScope ? pScope->pScope : pScope;
+			int parentLen = localPtr - tzSym;
+			
+			if (strchr(localPtr + 1, '.') != NULL) {
+				fatalerror("'%s' is a nonsensical reference to a nested local symbol", tzSym);
+			} else if (strlen(parent->tzName) != parentLen || strncmp(tzSym, parent->tzName, parentLen) != 0) {
+				yyerror("Not currently in the scope of '%.*s'", parentLen, tzSym);
+			}
+			
+			scope = parent;
+		}
+
+		if ((nsym = findsymbol(tzSym, scope)) != NULL) {
 			if (nsym->nType & SYMF_DEFINED) {
 				yyerror("'%s' already defined", tzSym);
 			}
@@ -642,14 +660,17 @@ sym_AddReloc(char *tzSym)
 		if (nsym) {
 			nsym->nValue = nPC;
 			nsym->nType |= SYMF_RELOC | SYMF_DEFINED;
+			if (localPtr) {
+				nsym->nType |= SYMF_LOCAL;
+			}
 			if (exportall) {
 			   nsym->nType |= SYMF_EXPORT;
 			}
-			nsym->pScope = NULL;
+			nsym->pScope = scope;
 			nsym->pSection = pCurrentSection;
 		}
 	}
-	pScope = findsymbol(tzSym, NULL);
+	pScope = findsymbol(tzSym, scope);
 }
 
 /*
@@ -705,7 +726,7 @@ sym_Export(char *tzSym)
 		/* only export symbols in pass 1 */
 		struct sSymbol *nsym;
 
-		if ((nsym = findsymbol(tzSym, 0)) == NULL)
+		if ((nsym = sym_FindSymbol(tzSym)) == NULL)
 			nsym = createsymbol(tzSym);
 
 		if (nsym)
@@ -713,7 +734,7 @@ sym_Export(char *tzSym)
 	} else {
 		struct sSymbol *nsym;
 
-		if ((nsym = findsymbol(tzSym, 0)) != NULL) {
+		if ((nsym = sym_FindSymbol(tzSym)) != NULL) {
 			if (nsym->nType & SYMF_DEFINED)
 				return;
 		}
@@ -732,7 +753,7 @@ sym_Global(char *tzSym)
 		/* only globalize symbols in pass 2 */
 		struct sSymbol *nsym;
 
-		nsym = findsymbol(tzSym, 0);
+		nsym = sym_FindSymbol(tzSym);
 
 		if ((nsym == NULL) || ((nsym->nType & SYMF_DEFINED) == 0)) {
 			if (nsym == NULL)

test/asm/local-wrong-parent.asm

@@ -0,0 +1,6 @@
+SECTION "sec", ROM0
+
+Parent:
+	db 0
+WrongParent.child
+	db 0

test/asm/local-wrong-parent.out

@@ -0,0 +1,3 @@
+ERROR: local-wrong-parent.asm(5):
+	Not currently in the scope of 'WrongParent'
+error: Assembly aborted in pass 1 (1 errors)!

test/asm/remote-local-explicit.asm

@@ -0,0 +1,7 @@
+SECTION "sec", ROM0
+
+Parent:
+Parent.child::
+	db 0
+NotParent:
+	dw Parent.child

test/asm/remote-local-noexist.asm

@@ -0,0 +1,7 @@
+SECTION "sec", ROM0
+
+Parent:
+.child:
+	db 0
+NotParent:
+	dw Parent.child.fail

test/asm/remote-local-noexist.out

@@ -0,0 +1,2 @@
+ERROR: remote-local-noexist.asm(7):
+	'Parent.child.fail' is a nonsensical reference to a nested local symbol

test/asm/remote-local.asm

@@ -0,0 +1,7 @@
+SECTION "sec", ROM0
+
+Parent:
+.child:
+	db 0
+NotParent:
+	dw Parent.child