Added ALIGN and END Pseudo-Ops to A02 Assembler

a02.c

@@ -18,7 +18,7 @@ int  orgadr;    //Origin Address
 int  curadr;    //Current Address
 int  lstadr;    //List Address
 
-struct sym {int block; char name[MAXLBL+1]; int bytes, value;};
+struct sym {int block; char name[MAXLBL+1]; int bytes, value, refrd;};
 struct sym symbol;          //Current Symbol
 struct sym symtbl[MAXSYM];  //Global Symbol Table
 int symcnt; //Number of Global Labels
@@ -31,6 +31,8 @@ char cmmnt[MAXSTR]; //Assembly Line Comment
 char mcode[MAXSTR]; //Generated Bytes
 char strng[MAXSTR]; //Parsed String
 
+int  opridx;         //Index into Operand
+
 unsigned char token, opmod;   //OpCode Token, Modifier
 unsigned int  amode;          //Addressing Modes
 int           zpage, opval;   //ZeroPage Flag, Operand Value
@@ -41,10 +43,11 @@ char bytstr[5];     //String Representation of Byte
 char inplin[MAXSTR]; //Input Buffer 
 char *linptr;        //Pointer into Input Buffer
 int  lineno;         //Input File Line Number
-int  opridx;         //Index into Operand
-int  passno;         //Assembler Pass Number (1 or 2)
 int  savlno;         //Line Number (Saved)
 
+int  passno;         //Assembler Pass Number (1 or 2)
+int  endasm;         //End Assembly Flag
+
 char prgnam[256]; //Assembler Path and Name (from Command Line)
 char inpnam[256]; //Input File Name
 char outnam[256]; //Output File Name
@@ -114,6 +117,14 @@ void setsym(int value, int bytes) {
   symbol.value = value;
   if (bytes) symbol.bytes = bytes;
   else symbol.bytes = (value > 0xFF) ? 2 : 1;
+  symbol.refrd = FALSE;
+}
+
+/* Add Character to Beginning of String */
+void pfxstr(char c, char* s) {
+    for (int i=strlen(s)+1; i; i--) 
+      s[i] = s[i-1]; //Copy All Characters to the Right
+    s[0] = c;        //Insert Character at Beginning
 }
 
 /* Parse Label from Input Line 
@@ -137,10 +148,8 @@ int plabel(void) {
     strcpy(symbol.name, label);
     setsym(curadr, 0);
   }
-  if (block) {
+  if (block) pfxstr('.', label);
-    for (int i=strlen(label)+1; i; i--) label[i] = label[i-1]; 
+  skpspc(); //Skip to Mnemonic, Comment, or EOL
-    label[0] = '.';
-  }
   return found;
 }
 
@@ -205,6 +214,7 @@ struct sym *evlsym() {
   for (int i=0; name[i]; i++) if (opridx<MAXSTR) oprnd[opridx++] = name[i];
   struct sym *result = fndsym(block, name);
   if (passno == 2 && result == NULL) xerror("Undefined Symbol %s\n", name);
+  if (result) result->refrd = TRUE; //Symbol was Referenced
   return result;
 }
 
@@ -299,6 +309,16 @@ void asmwrd(void) {
   } while (cpychr(','));
 }
 
+/* Assemble FILL Pseudo-Op */
+void asmaln(void) {
+  if (DEBUG) puts("Assembling ALIGN Pseudo-Op");
+  int size = evlopd(0xFFFF); if (size < 2) return;
+  if (DEBUG) printf("Aligning to %d Bytes\n", size);
+  int fill = size - (curadr % size); if (fill == size) return;
+  if (DEBUG) printf("Filling %d Bytes\n", fill);
+  for (int i=0; i<fill; i++) outbyt(0);
+}
+
 /* Assemble FILL Pseudo-Op */
 void asmfll(void) {
   if (DEBUG) puts("Assembling FILL Pseudo-Op");
@@ -357,9 +377,14 @@ void asminf(void) {
   if (DEBUG) printf("Include File Set to Name to ''\n", incnam);
 }
 
+/* Assemble END Pseudo-Op */
+void asmend(void) {
+  endasm = TRUE;
+}
+
 /* Assemble Pseudo-Op */
-int asmpso(void) {
+int asmpso(int dot) {
-  if (lkpopc(psolst) == FALSE) return FALSE;
+  if (lkpopc(psolst) == FALSE && dot == FALSE) return FALSE; 
   skpspc();
   if (DEBUG) printf("Assembling Pseudo-Op %s, Token '%c'\n", mnmnc, token);
   switch (token) {
@@ -372,14 +397,18 @@ int asmpso(void) {
     case 'I': asminf(); break;  //INCLude
     case '*': asmorg(); break;  //ORG
     case 'P': asmprc(); break;  //PROCessor
+    case 'E': asmend(); break;  //END
+    case 'A': asmaln(); break;  //ALIGn
     default: xerror("Undefined Pseudo-Op %s\n", mnmnc);
   }
+  if (dot) pfxstr('.', mnmnc);
   return TRUE;
 }
 
 /* Lookup Opcode */
 int lkpopc(struct opc opl[]) {
   if (DEBUG) printf("Looking up Mnemonic %s\n", mnmnc);
+  token = 0xFF; //Set Token to Invalid
   char mne[5]; strncpy(mne, mnmnc, 4); mne[4] = 0; //Truncate Mnemonic to Four Characters
   for (int i=0; opl[i].name[0]; i++) {
     if (strcmp(opl[i].name, mne)) continue;
@@ -498,9 +527,9 @@ void dbgopc(void) {
 }
 
 /* Assemble Opcode */
-int asmopc(void) {
+int asmopc(int dot) {
   opmod = 0;
-  if (asmpso()) return TRUE; //Check For/Assemble Pseudo-Op
+  if (asmpso(dot)) return TRUE; //Check For/Assemble Pseudo-Op
   if (lkpopc(opclst) == FALSE) xerror("Invalid Mnemonic %s\n", mnmnc);
   if (DEBUG) printf("Assembling Opcode Token 0x%02X, ", token);
   if (DEBUG) printf("Addressing Mode Mask 0x%04X\n", amode);
@@ -526,9 +555,10 @@ int asmopc(void) {
  * Returns: Label Found (TRUE/FALSE) */
 int pmnmnc(void) {
   if (DEBUG) puts("Parsing Mnemonic");
+  int dot = cpychr('.'); //Optional Dot before Pseudo-Op
   int found = pword(TRUE, mnmnc);
   opridx = 0; //Initialize Operand Index
-  if (found) asmopc();
+  if (found) asmopc(dot);
   oprnd[opridx] = 0; //Terminate Operand String
   return found;
 }
@@ -568,6 +598,7 @@ void clsinc(void) {
   incfil = NULL;
   incnam[0] = 0;
   lineno = savlno;
+  endasm = FALSE; //Clear End Flag for Return to Maun File
 }
 
 /* Assemble Input File (Two Pass)        *
@@ -576,6 +607,7 @@ void clsinc(void) {
  * Uses: inplin - Input Line Buffer      *
  *       lineno - Input File Line Number */
 void asmfil(int pass) {
+  endasm = FALSE;   //Reset End Assembly Flag
   passno = pass;    //Assembly Pass Number
   if (DEBUG) printf("Assembling Pass %d\n", pass);
   lineno = 1;       //Initialize Input File Line Number
@@ -586,7 +618,7 @@ void asmfil(int pass) {
   while (TRUE) {
     if (incfil) linptr = fgets(inplin, MAXSTR, incfil);
     else linptr = fgets(inplin, MAXSTR, inpfil);
-    if (linptr == NULL) {if (incfil) {clsinc(); continue;} else break;}
+    if (endasm || linptr == NULL) {if (incfil) {clsinc(); continue;} else break;}
     if (DEBUG) printf("%05d %04X: %s", lineno, curadr, inplin);
     lstadr = curadr;  //Set List Address
     mcode[0] = 0; //Clear Generated Macbine Code
@@ -606,9 +638,10 @@ void asmfil(int pass) {
 
 /* Print Symbol Table */
 void prtsym(void) {
-  fprintf(lstfil, "\n%s Symbol Table\nBlock Name     Size Value\n", "Global");
+  fprintf(lstfil, "\n%s Symbol Table\nBlock Name     Size Value Rfd\n", "Global");
   for (int i=0; i<symcnt; i++) {
-    fprintf(lstfil, "%5d %-8s %4d %5d\n", symtbl[i].block, symtbl[i].name, symtbl[i].bytes, symtbl[i].value);
+    int refrd = (symtbl[i].refrd) ? '*' : ' ';
+    fprintf(lstfil, "%5d %-8s %4d %5d  %c \n", symtbl[i].block, symtbl[i].name, symtbl[i].bytes, symtbl[i].value, refrd);
   }
 }
 
@@ -653,7 +686,7 @@ int main(int argc, char *argv[]) {
     lstfil = opnfil(lstnam, "w");   //  Open List File
   asmfil(1);                        //Assemble Input File (First Pass)
   asmfil(2);                        //Assemble Input File (First Pass)
-  if (lstfil) prtsym();             //Print Symbol Table
+  if (lstfil && symcnt) prtsym();   //Print Symbol Table
   exit(0);                          //Exit with No Errors
 }
 

a02.h

@@ -42,8 +42,8 @@ struct amd amdesc[] = {
 struct opc {char name[5], token; int amode;};
 struct opc psolst[] = {
   {"BYTE", 'B', 0}, {"HEX", 'H'}, {"WORD", 'W', 0}, {"EQU", '=', 0}, {"FILL", 'F', 0}, 
-  {"INCL", 'I', 0}, {"SUBR", 'S', 0}, {"ORG", '*', 0}, {"PROC", 'P', 0}, 
+  {"INCL", 'I', 0}, {"SUBR", 'S', 0}, {"DC", 'B', 0}, {"DS", 'F', 0}, {"ALIG", 'A', 0},
-  {"DC", 'B', 0}, {"DS", 'F', 0}, {"", 0, 0}
+  {"ORG", '*', 0}, {"PROC", 'P', 0}, {"END", 'E', 0}, {"", 0, 0}
 };
 
 struct opc opclst[] = {