Minor code cleanup and added an extra flag to the compiler. If a symbol is a label it will now hold a reference to the opcode and by extension the offset into the file it points to.

Makefile

@@ -1,5 +1,5 @@
 CC = gcc
-CFLAGS=-g -Wall -DDEBUG -Wpedantic
+CFLAGS=-g -Wall -DDEBUG -Wpedantic -Wextra
 SRCDIR=src
 OBJDIR=obj
 SRCS=$(wildcard $(SRCDIR)/*.c)
@@ -35,7 +35,7 @@ clean:
 	rm -rf $(BINDIR)/* $(OBJDIR)/*
 
 test:
-	$(BIN) misc/test.asm
+	$(BIN) misc/another_test.asm
 
 disass:
 	objdump -S --disassemble $(OBJDIR)/$(FILE).o > $(OBJDIR)/$(FILE).s

includes/symbols_table.h

@@ -8,6 +8,7 @@
 #include <string.h>
 #include <sys/types.h>
 #include "opcodes.h"
+#include "token.h"
 
 #define SYMBOLSTABLE_DEFAULT_CAPACITY 128
 
@@ -16,6 +17,7 @@ typedef struct {
     int Address;
     int Resolved;
     int Length;
+    Token* References;
 } Symbol;
 
 typedef struct {

misc/another_test.asm

@@ -23,6 +23,8 @@ draw_loop:
 _end:
     jmp _end
 
+.db NewMsg "My message", 0
+
 ; Returns the length of a NULL terminated string
 ; Arguments: R1 - Pointer to the string
 ; Returns: R2 - Contains the length of the string

src/main.c

@@ -38,7 +38,7 @@ int main(int argc, char* args[]) {
     assemble();
 
     printf("\nBytes:\n");
-    for(int i = 0; i < sizeof(mem); i++) { 
+    for(unsigned long i = 0; i < sizeof(mem); i++) { 
         if (i != 0 && i % 8 == 0) printf("\n");
         printf("%02X ", mem[i] & 0xFF);
     }

src/opcodes.c

@@ -1,4 +1,5 @@
 #include "../includes/opcodes.h"
+#include <ctype.h>
 #include <stdlib.h>
 #include <string.h>
 
@@ -67,7 +68,7 @@ void GetRegisterText(Registers reg, char buffer[3]) {
 int IsOpcode(const char* text, Mnemonic* opcode) {
     if (!text) return 0;
 
-    for(int i = 0; i < sizeof(instructions) / sizeof(struct _instruction); i++) {
+    for(unsigned long i = 0; i < sizeof(instructions) / sizeof(struct _instruction); i++) {
         if (strcmp(instructions[i].Name, text) == 0) {
             if (opcode) *opcode = instructions[i].Mnemonic;
             return 1;
@@ -86,25 +87,11 @@ int IsRegister(const char* text, Registers* reg) {
     if (length != 2) return 0;
     if (text[0] != 'r') return 0;
 
-    switch(text[1]) {
-        case '1':
-            r--;
-        case '2':
-            r--;
-        case '3':
-            r--;
-        case '4':
-            r--;
-        case '5':
-            r--;
-        case '6':
-            r--;
-        case '7':
-            r--;
-        case '8':
-            if (reg) *reg = r;
-            return 1;
-        default:
-            return 0;
-    }
+    if (!isdigit(text[1])) return 0;
+
+    r = text[1] - 0x31;
+
+    if (reg) *reg = r;
+
+    return 1;
 }

src/parser.c

@@ -13,7 +13,7 @@ int CurrentToken = 0;
 void PrintSymbols(void);
 void RemoveCurrentToken(void);
 void HandleAssemblerDirective(void);
-void HandleOpcode(void);
+Token* ExpectMnemonic(void);
 void AdvanceParser(void);
 void IgnoreParserLine(void);
 Token* PeekToken(void);
@@ -46,7 +46,7 @@ SymbolTable* ParseTokens(List* tokens) {
                 HandleAssemblerDirective();
                 break;
             case MnemonicClass:
-                HandleOpcode();
+                ExpectMnemonic();
                 break;
             case LabelClass:
                 {
@@ -58,7 +58,7 @@ SymbolTable* ParseTokens(List* tokens) {
                         exit(1);
                     }
 
-                    if (!found) AddSymbolToTable(t->Lemexe, PC, 1, SymbolsTable);
+                    if (!found) symbol = AddSymbolToTable(t->Lemexe, PC, 1, SymbolsTable);
                     else 
                     {
                         symbol->Address = PC;
@@ -68,6 +68,8 @@ SymbolTable* ParseTokens(List* tokens) {
                     RemoveCurrentToken(); //label
                     
                     ExpectLineEndOrFileEnd(RemoveExpected);
+                    
+                    symbol->References = ExpectMnemonic();
                 }
                 break;
             default:
@@ -119,9 +121,15 @@ void HandleAssemblerDirective() {
     }
 }
 
-void HandleOpcode(void) {
+Token* ExpectMnemonic(void) {
     Token* opcode = PeekToken();
 
+    if (opcode->Class != MnemonicClass) {
+        fprintf(stderr, "Syntax error on line %d: expected mnemonic.\n", opcode->LineNumber);
+
+        exit(1);
+    }
+
     AdvanceParser();
 
     switch(opcode->Value.Mnemonic) {
@@ -372,6 +380,8 @@ void HandleOpcode(void) {
     }
 
     ExpectLineEndOrFileEnd(ForwardParser);
+    
+    return opcode;
 }
 
 void ExpectPuncuation(TokenPunctuation punctuation, ExpectOptions options) {
@@ -479,13 +489,18 @@ void ExpectLineEndOrFileEnd(ExpectOptions options) {
 }
 
 void PrintSymbols(void) {
-    //char mn[12];
+    char mn[12];
     printf("-----SYMBOLS-----\n");
     for(int i = 0; i < SymbolsTable->Size; i++) {
         Symbol* symbol = SymbolsTable->Symbols[i];
 
-        printf("[%s] %s [%d] [Width: %d]", symbol->Resolved == 0 ? "Unresolved" : "Resolved", symbol->Name, symbol->Address, symbol->Length);
+        if (!symbol->References)
+            printf("[%s] %s [%d] [Width: %d]", symbol->Resolved == 0 ? "Unresolved" : "Resolved", symbol->Name, symbol->Address, symbol->Length);
+        else {
+            GetMnemonicText(symbol->References->Value.Mnemonic, mn);
+            printf("[%s] %s [%d] [Width: %d] -> [%s] Line %d", symbol->Resolved == 0 ? "Unresolved" : "Resolved", symbol->Name, symbol->Address, symbol->Length, mn, symbol->References->LineNumber);
 
+        }
         printf("\n");
     }
     printf("-----SYMBOLS-----\n");