Added support for declaring a variable with the '.db' directive. Address calculations still need to be done, but at the very least the variable's name is showing up in the symbols table.

src/parser.c

@@ -1,11 +1,14 @@
 #include "../includes/parser.h"
 #include <stdarg.h>
+#include <stdio.h>
 #include <stdlib.h>
 
 #ifndef HIGHMEMORY
 #define HIGHMEMORY 65535 //64KiB - 1 AKA 0xFFFF
 #endif
 
+#define HEAPTOP HIGHMEMORY
+
 typedef struct {
     Token* token;
     int address;
@@ -18,10 +21,12 @@ int CurrentToken = 0;
 void AddSymbol(Token*, int);
 void PrintSymbols(void);
 void HandleOperation(void);
+void HandleAssemblerDirective(void);
 void AdvanceParser(void);
 Token* PeekToken(void);
 int ParserAtEnd(void);
 int Expect(int, ...);
+int ExpectTokenClass(int, ...);
 Token* GetSymbol(char*);
 List* SymbolsTable;
 unsigned int ProgramCounter = 0;
@@ -53,6 +58,9 @@ void ParseTokens(List* tokens) {
                     ProgramCounter++;
                     HandleOperation();
                 }
+                else if (t->token_class == Directive) {
+                    HandleAssemblerDirective();
+                }
 
                 AdvanceParser();
                 
@@ -65,6 +73,37 @@ void ParseTokens(List* tokens) {
     printf("Program Counter: %d\n", ProgramCounter);
 }
 
+void HandleAssemblerDirective(void) {
+    Token* token = PeekToken();
+    AdvanceParser();
+
+    if (token->type == DB) {
+        token = PeekToken();
+        if (!Expect(1, IDENTIFIER)) { 
+            fprintf(stderr, "Expected identifier on line %d\n", PeekToken()->line);
+            exit(1);
+        }
+        //This should be done only after the directive is parsed fully.
+        AddSymbol(token, HEAPTOP);
+
+        if (PeekToken()-> type == STRING) {
+            AdvanceParser();
+
+            if (PeekToken()-> type == COMMA) {
+                AdvanceParser();
+                if (PeekToken()-> type != NUMBER) {
+                    fprintf(stderr, "Expected string termination byte on line %d\n", PeekToken()->line);
+                    exit(1);
+                }
+                // else {
+                //     //Setup string and return
+                //     return;
+                // }
+            }
+        }
+    }
+}
+
 void HandleOperation(void) {
     const Instruction* inst = GetOpcodeDetails(PeekToken()->type);
 
@@ -76,6 +115,11 @@ void HandleOperation(void) {
 
     if (inst->parameter_one && PeekToken()->token_class > 0) {
         printf("Matched '%s'\n", PeekToken()->lexeme);
+
+        if (inst->parameter_one == Reg) {
+            //Encode the register number here.
+        }
+
         AdvanceParser();
     }
 
@@ -98,23 +142,43 @@ void HandleOperation(void) {
     }
 }
 
-// int Expect(int count, ...) {
-//     va_list list;
+int ExpectTokenClass(int count, ...) {
+    va_list list;
+    Token* token = PeekToken();
 
-//     va_start(list, count);
+    va_start(list, count);
 
-//     for(int i = 0; i < count; i++) {
-//         if (va_arg(list, TokenClass) == PeekToken()->token_class) {
-//             va_end(list);
-//             //advance
-//             return 1;
-//         }
-//     }
+    for(int i = 0; i < count; i++) {
+        if (va_arg(list, TokenClass) == token->token_class) {
+            va_end(list);
+            AdvanceParser();
+            return 1;
+        }
+    }
 
-//     va_end(list);
+    va_end(list);
 
-//     return 0;
-// }
+    return 0;
+}
+
+int Expect(int count, ...) {
+    va_list list;
+    Token* token = PeekToken();
+
+    va_start(list, count);
+
+    for(int i = 0; i < count; i++) {
+        if (va_arg(list, TokenType) == token->type) {
+            va_end(list);
+            AdvanceParser();
+            return 1;
+        }
+    }
+
+    va_end(list);
+
+    return 0;
+}
 
 void PrintSymbols(void) {
     printf("-----SYMBOLS-----\n");