From a520a327be9e16725d7b2cf85551eabe984d84a5 Mon Sep 17 00:00:00 2001
From: ketmar <ketmar@ketmar.no-ip.org>
Date: Fri, 16 Mar 2012 16:26:05 +0200
Subject: [PATCH] alot of things changed in code file format; preparing for
 room local scripts

---
 src/awasm.c       | 220 ++++++++++++++++++++++++++++++++++++++++++------------
 src/awish.c       |  12 ++-
 src/gameglobals.c |  98 ++++++++++++++++++------
 src/gameglobals.h |  10 ++-
 4 files changed, 264 insertions(+), 76 deletions(-)

diff --git a/src/awasm.c b/src/awasm.c
index 9f77f2f..105a2df 100644
--- a/src/awasm.c
+++ b/src/awasm.c
@@ -359,6 +359,7 @@ static int nextToken (void) {
 typedef struct LabelRefInfo {
   struct LabelRefInfo *next;
   int pc;
+  int size;
 } LabelRefInfo;
 
 
@@ -367,8 +368,9 @@ typedef struct LabelInfo {
   char *name;
   int type; // LB_XXXX
   int value; // code && <0: not defined yet (forward ref)
-  int ext; // extern?
+  int ext; // extern (<0), public(>0), normal(0)
   LabelRefInfo *fixes; // for undefined code labels
+  LabelRefInfo *refs; // for externals
   int used;
 } LabelInfo;
 
@@ -389,7 +391,7 @@ static LabelRefInfo *lrefRemoveDups (LabelRefInfo *list) {
     int dup = 0;
     //
     if (list != NULL) {
-      for (LabelRefInfo *r = list; r != c; r = r->next) if (r->pc == c->pc) { dup = 1; break; }
+      for (LabelRefInfo *r = list; r != c; r = r->next) if (r->pc == c->pc && r->size == c->size) { dup = 1; break; }
     }
     //
     if (dup) {
@@ -414,12 +416,11 @@ static LabelRefInfo *lrefRemoveDups (LabelRefInfo *list) {
 static LabelRefInfo *addLabelRefToList (LabelRefInfo *list, int pc) {
   LabelRefInfo *res;
   //
-  //for (res = list; res != NULL; res = res->next) if (res->pc == pc) return list;
-  //
   res = calloc(1, sizeof(LabelRefInfo));
   if (res == NULL) fatal("out of memory");
   res->next = list;
   res->pc = pc;
+  res->size = 2;
   return res;
 }
 
@@ -434,10 +435,22 @@ static void freeLabelRefList (LabelRefInfo *list) {
 }
 
 
+static void addExternRef (LabelInfo *l, int pc, int size) {
+  if (l != NULL && l->ext < 0) {
+    if (size <= 0) {
+      size = (l->type == LB_CODE || l->type == LB_CONST || l->type == LB_SVAR) ? 2 : 1;
+    }
+    l->refs = addLabelRefToList(l->refs, pc);
+    l->refs->size = size;
+  }
+}
+
+
 static void addLabelRef (LabelInfo *l, int pc) {
   if (l != NULL) {
     l->used = 1;
-    if (l->type == LB_CODE) {
+    addExternRef(l, pc, -1);
+    if (l->type == LB_CODE && l->ext >= 0) {
       // record fixup info for undefined code labels
       if (l->value < 0) l->fixes = addLabelRefToList(l->fixes, pc);
       // record reference info for code labels
@@ -463,7 +476,7 @@ static void fixupLabelRefs (LabelInfo *l, int pc) {
 
 static void checkLabels (void) {
   for (LabelInfo *l = labels; l != NULL; l = l->next) {
-    if (l->type == LB_CODE && l->value < 0) fatal("undefined %slabel: '%s'", l->used?"":"not referenced ", l->name);
+    if (l->type == LB_CODE && l->ext >= 0 && l->value < 0) fatal("undefined %slabel: '%s'", l->used?"":"not referenced ", l->name);
     if (!l->used) { l->used = -1; fprintf(stderr, "WARNING: unused %s label '%s'\n", ltnames[l->type], l->name); }
   }
 }
@@ -476,6 +489,7 @@ static void freeLabels (void) {
     //
     labels = l->next;
     freeLabelRefList(l->fixes);
+    freeLabelRefList(l->refs);
     free(l->name);
     free(l);
   }
@@ -489,10 +503,11 @@ static void freeLocalLabels (int onlyVars) {
     LabelInfo *n = l->next;
     //
     if ((!onlyVars || l->type != LB_CODE) && l->name[0] == '.') {
-      if (l->type == LB_CODE && l->value < 0) fatal("undefined %slabel: '%s'", l->used?"":"not referenced ", l->name);
+      if (l->type == LB_CODE && l->ext >= 0 && l->value < 0) fatal("undefined %slabel: '%s'", l->used?"":"not referenced ", l->name);
       if (!l->used) { l->used = -1; fprintf(stderr, "WARNING: unused %s label '%s'\n", ltnames[l->type], l->name); }
       //if (l->type == LB_CODE && l->value < 0) fatal("undefined label: '%s'", l->name);
       freeLabelRefList(l->fixes);
+      freeLabelRefList(l->refs);
       free(l->name);
       free(l);
       if (p != NULL) p->next = n; else labels = n;
@@ -526,6 +541,7 @@ static LabelInfo *addLabel (const char *name) {
   l->value = -1;
   l->ext = 0;
   l->fixes = NULL;
+  l->refs = NULL;
   l->next = labels;
   labels = l;
   return l;
@@ -658,10 +674,11 @@ static void emitOperand (OperandInfo *op) {
       // from label
       op->l->used = 1;
       switch (op->l->type) {
-        case LB_GVAR: emitByte(op->l->value|0x80); break;
-        case LB_TVAR: emitByte(op->l->value); break;
+        case LB_GVAR: addLabelRef(op->l, pc); emitByte(op->l->value|0x80); break;
+        case LB_TVAR: addLabelRef(op->l, pc); emitByte(op->l->value); break;
         case LB_SVAR:
           emitByte(127); // special
+          addLabelRef(op->l, pc);
           emitByte(op->l->value&0xff);
           emitByte((op->l->value>>8)&0xff);
           break;
@@ -1070,7 +1087,7 @@ static void parseInlcude (void) {
 }
 
 
-static void parseVarList (int type, int local) {
+static void parseVarList (int type, int local, int gotext) {
   for (;;) {
     LabelInfo *l;
     //
@@ -1078,19 +1095,33 @@ static void parseVarList (int type, int local) {
     if (tstr[0] == '.' && local <= 0) fatal("invalid variable name: '%s'", tstr);
     if (tstr[0] != '.' && local > 0) fatal("invalid variable name: '%s'", tstr);
     l = findLabel(tstr);
-    if (l != NULL) fatal("duplicate variable or label: '%s'", tstr);
-    l = addLabel(tstr);
-    l->type = type;
-    if (local > 0 && vtloc <= vtlast) fatal("too many local vars");
-    l->value = local>0?(--vtloc):(type==LB_GVAR?vglast++:vtlast++);
-    if (local < 0) l->ext = 1;
+    if (l != NULL) {
+      if (gotext) {
+        if (l->ext >= 0) fatal("can't declare existing label as extern: '%s'", tstr);
+        if (l->type != type) fatal("can't change existing extern label type: '%s'", tstr);
+      } else {
+        fatal("duplicate variable or label: '%s'", tstr);
+      }
+    }
+    if (l == NULL) {
+      l = addLabel(tstr);
+      l->type = type;
+      if (local > 0 && vtloc <= vtlast) fatal("too many local vars");
+      if (gotext) {
+        l->value = 0;
+      } else {
+        l->value = (local>0)?(--vtloc):(type==LB_GVAR?vglast++:vtlast++);
+      }
+      if (local < 0) l->ext = 1;
+    }
+    if (gotext) l->ext = -1;
     if (l->value > 126) fatal("too many vars");
     if (nextToken() != ',') break;
   }
 }
 
 
-static void parseExterns (void) {
+static void parsePublics (void) {
   for (;;) {
     LabelInfo *l;
     //
@@ -1130,19 +1161,32 @@ static void parseLocList (void) {
 }
 
 
-static void parseConst (int ext) {
+static void parseConst (int ext, int gotext) {
   LabelInfo *l;
   //
   if (nextToken() != TK_ID) fatal("identifier expected");
   if (tstr[0] == '.') fatal("invalid constant name: '%s'", tstr);
   l = findLabel(tstr);
-  if (l != NULL) fatal("constant must be unique: '%s'", tstr);
-  l = addLabel(tstr);
-  if (nextToken() == '=') nextToken();
-  if (token != TK_NUM) fatal("constant must be numeric");
-  l->type = LB_CONST;
-  l->value = tint;
-  l->ext = ext;
+  if (l != NULL) {
+    if (gotext) {
+      if (l->ext >= 0) fatal("can't declare existing label as extern: '%s'", tstr);
+      if (l->type != LB_CONST) fatal("can't change existing extern label type: '%s'", tstr);
+    } else {
+      fatal("constant must be unique: '%s'", tstr);
+    }
+  }
+  if (l == NULL) {
+    l = addLabel(tstr);
+    l->type = LB_CONST;
+    l->value = 0;
+  }
+  if (!gotext) {
+    if (nextToken() == '=') nextToken();
+    if (token != TK_NUM) fatal("constant must be numeric");
+    l->value = tint;
+  }
+  if (ext) l->ext = 1;
+  if (gotext) l->ext = -1;
   nextToken();
 }
 
@@ -1251,11 +1295,14 @@ static void doReturn (void) {
 }
 
 
-static void parseLabel (void) {
+static void parseLabel (int gotext) {
   LabelInfo *l;
   //
+  if (gotext && tstr[0] == '.') fatal("can't declare local extern label: '%s'", tstr);
   if (tstr[0] != '.' && tstr[0] != '@') {
-    if (procname[0]) fatal("you can not define non-special global labels inside proc ('%s')", procname);
+    if (!gotext) {
+      if (procname[0]) fatal("you can not define non-special global labels inside proc ('%s')", procname);
+    }
     freeLocalLabels(0); // vars and code
   }
   if (tstr[0] == '@') {
@@ -1266,6 +1313,10 @@ static void parseLabel (void) {
   }
   l = findLabel(tstr);
   if (l != NULL) {
+    if (gotext) {
+      if (l->ext >= 0) fatal("can't declare existing label as extern: '%s'", tstr);
+      if (l->type != LB_CODE) fatal("can't change existing extern label type: '%s'", tstr);
+    }
     if (l->type != LB_CODE || l->value >= 0) fatal("duplicate label: '%s'", tstr);
     fixupLabelRefs(l, pc);
   } else {
@@ -1273,6 +1324,7 @@ static void parseLabel (void) {
     l->type = LB_CODE;
     l->value = pc;
   }
+  if (gotext) l->ext = -1;
   nextToken();
 }
 
@@ -1287,6 +1339,7 @@ static void parseDB (void) {
       if (l->type == LB_CODE) fatal("bad label type: '%s'", l->name);
       l->used = 1;
       tint = l->value;
+      addExternRef(l, pc, 1);
     } else if (token != TK_NUM) {
       fatal("number expected");
     }
@@ -1310,6 +1363,7 @@ static void parseDW (void) {
         //fatal("unknown label: '%s'", tstr);
       }
       addLabelRef(l, pc);
+      addExternRef(l, pc, 2);
       tint = l->value;
     } else if (token != TK_NUM) {
       fatal("number expected");
@@ -1399,6 +1453,7 @@ static void parseDAscii (int zeroend) {
           if (l == NULL) fatal("unknown label: '%s'", tstr);
           if (l->type == LB_CODE) fatal("bad label type: '%s'", l->name);
           l->used = 1;
+          addExternRef(l, pc, 1);
           tint = l->value;
         } else if (token != TK_NUM) {
           fatal("number expected");
@@ -1413,7 +1468,9 @@ static void parseDAscii (int zeroend) {
 
 
 static void process (void) {
+  int gotext = 0;
   LabelInfo *l = addLabel("retval");
+  //
   l->type = LB_TVAR;
   l->value = VM_VARS_SIZE-1;
   //
@@ -1424,45 +1481,81 @@ static void process (void) {
     int opc;
     //
     if (token == TK_LABELDEF) {
+      if (strcmp(tstr, "extern") == 0) {
+        if (gotext) fatal("double 'extern'");
+        gotext = 1;
+        nextToken();
+        continue;
+      }
       // new label or operator
       if (strcmp(tstr, "include") == 0) {
         parseInlcude();
+        continue;
       } else if (strcmp(tstr, "defloc") == 0) {
+        if (gotext) fatal("extern labels must not be locals");
         parseLocList();
       } else if (strcmp(tstr, "defgvar") == 0) {
-        parseVarList(LB_GVAR, 0);
+        parseVarList(LB_GVAR, 0, gotext);
       } else if (strcmp(tstr, "defevar") == 0) { // extern global
-        parseVarList(LB_GVAR, -1);
+        parseVarList(LB_GVAR, -1, gotext);
       } else if (strcmp(tstr, "deftvar") == 0) {
         freeLocalLabels(1); // only vars
         vtloc = VM_VARS_SIZE;
-        parseVarList(LB_TVAR, 0);
+        parseVarList(LB_TVAR, 0, gotext);
       } else if (strcmp(tstr, "defetvar") == 0) {
         freeLocalLabels(1); // only vars
         vtloc = VM_VARS_SIZE;
-        parseVarList(LB_TVAR, -1);
+        parseVarList(LB_TVAR, -1, gotext);
       } else if (strcmp(tstr, "deflvar") == 0) {
-        parseVarList(LB_TVAR, 1);
-      } else if (strcmp(tstr, "extern") == 0) {
-        parseExterns();
+        if (gotext) fatal("extern labels must not be locals");
+        parseVarList(LB_TVAR, 1, gotext);
+      } else if (strcmp(tstr, "public") == 0) {
+        if (gotext) fatal("invalid extern label declaration");
+        parsePublics();
       } else if (strcmp(tstr, "proc") == 0 || strcmp(tstr, "eproc") == 0) {
+        if (gotext) fatal("invalid extern label declaration");
         parseProc(tstr[0] == 'e');
       } else if (strcmp(tstr, "endp") == 0) {
+        if (gotext) fatal("invalid extern label declaration");
         parseEndP();
       } else if (strcmp(tstr, "const") == 0 || strcmp(tstr, "econst") == 0) {
-        parseConst(tstr[0] == 'e');
+        parseConst(tstr[0] == 'e', gotext);
       } else if (strcmp(tstr, "db") == 0) {
+        if (gotext) fatal("invalid extern label declaration");
         parseDB();
       } else if (strcmp(tstr, "dw") == 0) {
+        if (gotext) fatal("invalid extern label declaration");
         parseDW();
       } else if (strcmp(tstr, "da") == 0) {
+        if (gotext) fatal("invalid extern label declaration");
         parseDAscii(0);
       } else if (strcmp(tstr, "dz") == 0) {
+        if (gotext) fatal("invalid extern label declaration");
         parseDAscii(1);
       } else {
-        parseLabel();
+        parseLabel(gotext);
       }
+      gotext = 0;
       continue;
+    } else {
+      if (gotext) {
+        LabelInfo *l;
+        //
+        if (token != TK_ID) fatal("label declaration expected after 'extern'");
+        if (tstr[0] == '.') fatal("extern label can't be local: '%s'", tstr);
+        l = findLabel(tstr);
+        if (l != NULL) {
+          if (l->ext >= 0) fatal("can't declare existing label as extern: '%s'", tstr);
+          if (l->type != LB_CODE) fatal("can't change existing extern label type: '%s'", tstr);
+        } else {
+          l = addLabel(tstr);
+          l->type = LB_CODE;
+          l->value = 0;
+          l->ext = -1;
+        }
+        nextToken();
+        continue;
+      }
     }
     //
     if (token < TK_VM_OPERATOR) fatal("mnemonics expected");
@@ -1608,14 +1701,12 @@ static int cfWriteRels (FILE *fl) {
 }
 
 
-static int cfWriteLabels (FILE *fl) {
+static int cfWritePublicLabels (FILE *fl) {
   for (LabelInfo *l = labels; l != NULL; l = l->next) {
-    if (l->ext) {
+    if (l->ext >= 0 && l->name[0]) {
       int len = strlen(l->name);
       //
-      if (len < 1) continue;
-      //
-      if (cfWriteByte(fl, l->type) != 0) return -1;
+      if (cfWriteByte(fl, l->type|(l->ext>0?0x80:0)) != 0) return -1;
       //
       switch (l->type) {
         case LB_GVAR:
@@ -1640,27 +1731,60 @@ static int cfWriteLabels (FILE *fl) {
 }
 
 
+static int cfWriteExtLabels (FILE *fl) {
+  for (LabelInfo *l = labels; l != NULL; l = l->next) {
+    if (l->ext < 0 && l->name[0] && l->refs != NULL) {
+      int len = strlen(l->name), rcnt = 0;
+      //
+      if (cfWriteByte(fl, l->type) != 0) return -1;
+      if (len > 255) len = 255;
+      if (cfWriteByte(fl, len) != 0) return -1;
+      for (int f = 0; f < len; ++f) if (cfWriteByte(fl, (unsigned char)(l->name[f])) != 0) return -1;
+      //
+      for (LabelRefInfo *r = l->refs; r != NULL; r = r->next) ++rcnt;
+      if (cfWriteWord(fl, rcnt) != 0) return -1;
+      for (LabelRefInfo *r = l->refs; r != NULL; r = r->next) {
+        if (cfWriteByte(fl, r->size) != 0) return -1;
+        if (cfWriteWord(fl, r->pc) != 0) return -1;
+      }
+    }
+  }
+  return 0;
+}
+
+
 static int writeCodeFile (FILE *fl) {
   static const char *sign = "AVM1";
-  int lcnt = 0;
+  int lcnt = 0, elcnt = 0;
   int rcnt = 0;
   //
   relrefs = lrefRemoveDups(relrefs);
   for (LabelRefInfo *r = relrefs; r != NULL; r = r->next) ++rcnt;
-  for (LabelInfo *l = labels; l != NULL; l = l->next) if (l->ext && l->name[0]) ++lcnt;
-  fprintf(stderr, "%d bytes of code, %d public labels, %d fixups\n", pc, lcnt, rcnt);
+  for (LabelInfo *l = labels; l != NULL; l = l->next) {
+    if (l->name[0]) {
+      if (l->ext >= 0) ++lcnt;
+      if (l->ext < 0) {
+        l->refs = lrefRemoveDups(l->refs);
+        if (l->refs != NULL) ++elcnt;
+      }
+    }
+  }
+  fprintf(stderr, "%d bytes of code, %d public labels, %d fixups, %d externs\n", pc, lcnt, rcnt, elcnt);
   //
   if (fwrite(sign, 4, 1, fl) != 1) return -1;
   // code size
   if (cfWriteWord(fl, pc) != 0) return -1;
-  // number of labels
-  if (cfWriteWord(fl, lcnt) != 0) return -1;
   // number of fixups
   if (cfWriteWord(fl, rcnt) != 0) return -1;
+  // number of extern labels
+  if (cfWriteWord(fl, elcnt) != 0) return -1;
+  // number of labels
+  if (cfWriteWord(fl, lcnt) != 0) return -1;
   //
   if (cfWriteCode(fl) != 0) return -1;
   if (cfWriteRels(fl) != 0) return -1;
-  if (cfWriteLabels(fl) != 0) return -1;
+  if (cfWriteExtLabels(fl) != 0) return -1;
+  if (cfWritePublicLabels(fl) != 0) return -1;
   //
   return 0;
 }
@@ -1687,6 +1811,7 @@ int main (int argc, char *argv[]) {
   //while (nextToken() != TK_EOF) printf("%d [%s] %d\n", token, tstr, tint); return 0;
   process();
   while (ictx != NULL) closeFile();
+  freeLocalLabels(0); // vars and code
   checkLabels();
   //if (argc > 3) dumpGlobalVars(argv[3]);
   {
@@ -1703,5 +1828,6 @@ int main (int argc, char *argv[]) {
     }
   }
   freeLabels();
+  freeLabelRefList(relrefs);
   return 0;
 }
diff --git a/src/awish.c b/src/awish.c
index 35ff38d..5f8deaa 100644
--- a/src/awish.c
+++ b/src/awish.c
@@ -351,13 +351,13 @@ int main (int argc, char *argv[]) {
     }
   }
   //
+  if (vmInitialize() != 0) fatal("can't init VM");
+  //
   memset(vmGVars, 0, sizeof(vmGVars));
-  //vmGVars[GVAR_KEY_QUIT] = 0;
-  //vmGVars[GVAR_KEY_START] = 0;
-  vmGVars[GVAR_GOOBERS] = goobers;
   vmRSTCB = awishRST;
   //
-  if (vmInitialize() != 0) fatal("can't init VM");
+  addLabel("flag_skip_title", LB_GVAR, 120, 1); // 1: public
+  vmGVars[120] = 0;
   //
   vmCodeSize = 100;
   if ((csz = loadVMCode(&resfile, vmCodeSize)) < 1) {
@@ -367,6 +367,10 @@ int main (int argc, char *argv[]) {
   vmCodeSize += csz;
   initLabels();
   //
+  //vmGVars[GVAR_KEY_QUIT] = 0;
+  //vmGVars[GVAR_KEY_START] = 0;
+  vmGVars[GVAR_GOOBERS] = goobers;
+  //
   vmSetPC(0, CODE_ENTRY_TITLE);
   if (vmExecuteBSR(0, CODE_ENTRY_MAIN_INIT, 0) != 0) fatal("can't initialize game");
   if (goobers) fprintf(stderr, "MAX LEVEL: %d\n", vmGVars[GVAR_MAX_LEVEL]);
diff --git a/src/gameglobals.c b/src/gameglobals.c
index d7a9ffb..055ff43 100644
--- a/src/gameglobals.c
+++ b/src/gameglobals.c
@@ -68,7 +68,7 @@ void freeLabelsUntilMark (void) {
 }
 
 
-static void labelAddMark (void) {
+void labelAddMark (void) {
   LabelInfo *l = malloc(sizeof(LabelInfo));
   //
   if (l == NULL) fatal("out of memory");
@@ -76,10 +76,29 @@ static void labelAddMark (void) {
   l->type = LB_MARK;
   l->value = -1;
   l->next = labels;
+  l->pub = 0;
   labels = l;
 }
 
 
+LabelInfo *addLabel (const char *name, int type, int value, int pub) {
+  if (name != NULL && name[0]) {
+    LabelInfo *l = malloc(sizeof(LabelInfo));
+    //
+    if (l == NULL) fatal("out of memory");
+    l->name = strdup(name);
+    if (l->name == NULL) fatal("out of memory");
+    l->type = type;
+    l->value = value;
+    l->pub = pub;
+    l->next = labels;
+    labels = l;
+    return l;
+  }
+  return NULL;
+}
+
+
 #define SECRET  (42)
 
 
@@ -110,9 +129,8 @@ static void labelAddMark (void) {
 int loadVMCode (ResFile *resfile, int pc) {
   int rsz = 0, pos = 0;
   char sign[4];
-  int csize, lcnt, rcnt;
+  int csize, lcnt, rcnt, elcnt;
   uint8_t *buf = loadResFile(resfile, 93, &rsz);
-  int *rels = NULL;
   //
   if (buf == NULL) return -1;
   for (int f = 4; f < rsz; ++f) buf[f] ^= SECRET;
@@ -121,24 +139,20 @@ int loadVMCode (ResFile *resfile, int pc) {
   if (memcmp(sign, "AVM1", 4) != 0) goto quitbufonly;
   //
   XREADW(csize, quitbufonly);
-  XREADW(lcnt, quitbufonly);
-  XREADW(rcnt, quitbufonly);
+  XREADW(rcnt, quitbufonly); // fixups
+  XREADW(elcnt, quitbufonly); // extern labels
+  XREADW(lcnt, quitbufonly); // labels
   if (pc < 0 || pc+csize > 65535) goto quitbufonly;
   //
-  if (goobers) fprintf(stderr, "code: %d bytes, %d public labels, %d relocations\n", csize, lcnt, rcnt);
+  if (goobers) fprintf(stderr, "code: %d bytes, %d public labels, %d relocations, %d externs\n", csize, lcnt, rcnt, elcnt);
   //
   XREAD(vmCode+pc, csize, quitbufonly);
   //
-  if (rcnt > 0) {
-    rels = calloc(rcnt, sizeof(int));
-    if (rels == NULL) fatal("out of memory");
-    for (int f = 0; f < rcnt; ++f) XREADW(rels[f], quitbufonly);
-  }
   // do relocations
   for (int f = 0; f < rcnt; ++f) {
     int rel, newpc, val;
     //
-    rel = rels[f];
+    XREADW(rel, quitbufonly);
     if (rel < 0 || rel+1 >= csize) goto quitbufonly;
     newpc = pc+rel; // fix here
     // get old value
@@ -152,15 +166,58 @@ int loadVMCode (ResFile *resfile, int pc) {
     vmCode[newpc+1] = (val>>8)&0xff;
   }
   //
-  labelAddMark();
+  // load extern labels and perform fixups
+  for (int f = 0; f < elcnt; ++f) {
+    char name[258];
+    int type, namelen;
+    int rcnt;
+    //
+    XREADB(type, quitbufonly);
+    XREADB(namelen, quitbufonly);
+    XREAD(name, namelen, quitbufonly);
+    XREADW(rcnt, quitbufonly);
+    //
+    if (type < LB_MIN_TYPE || type > LB_MAX_TYPE) goto quitbufonly;
+    if (namelen < 1) goto quitbufonly;
+    name[namelen] = 0;
+    //
+    for (int c = 0; c < rcnt; ++c) {
+      int xpc, size, val;
+      LabelInfo *l;
+      //
+      XREADB(size, quitbufonly);
+      XREADW(xpc, quitbufonly);
+      //
+      if (size != 1 && size != 2) goto quitbufonly;
+      if (xpc < 0 || xpc+size > csize) goto quitbufonly;
+      //
+      xpc += pc;
+      l = findLabel(name);
+      if (l == NULL) {
+        if (goobers) fprintf(stderr, "VM: unknown extern: '%s'\n", name);
+        goto quitbufonly;
+      }
+      val = l->value;
+      if (l->type == LB_GVAR) val |= 0x80;
+      fprintf(stderr, "%d: [%s]: ofs=%d, size=%d, value=%d (%d)\n", c, l->name, xpc, size, val, vmCode[xpc]);
+      if (size == 1 && (val < -128 || val > 255)) {
+        if (goobers) fprintf(stderr, "VM: extern too big: '%s'\n", name);
+        goto quitbufonly;
+      }
+      vmCode[xpc+0] = val&0xff;
+      if (size == 2) vmCode[xpc+1] = (val>>8)&0xff;
+    }
+  }
   //
+  labelAddMark(); // for this code labels
   for (int f = 0; f < lcnt; ++f) {
     unsigned char type, namelen, b;
+    char name[258];
     int value;
     //
     XREADB(type, quit);
     //
-    switch (type) {
+    switch (type&0x7f) {
       case LB_GVAR:
       case LB_TVAR:
         XREADB(b, quit);
@@ -181,16 +238,10 @@ int loadVMCode (ResFile *resfile, int pc) {
     }
     //
     XREADB(namelen, quit);
-    LabelInfo *l = malloc(sizeof(LabelInfo));
+    XREAD(name, namelen, quit);
+    name[namelen] = 0;
     //
-    if (l == NULL) fatal("out of memory");
-    l->name = calloc(namelen+1, 1);
-    if (l->name == NULL) fatal("out of memory");
-    l->type = type;
-    l->value = value;
-    l->next = labels;
-    labels = l;
-    XREAD(l->name, namelen, quit);
+    if (namelen > 0) addLabel(name, type&0x7f, value, type&0x80?1:0);
     //if (l->type == LB_CODE) printf("%d/%d: [%s] %d : %d\n", f, lcnt, l->name, l->value-pc, l->value);
   }
   //
@@ -199,7 +250,6 @@ int loadVMCode (ResFile *resfile, int pc) {
 quit:
   freeLabelsUntilMark();
 quitbufonly:
-  if (rels) free(rels);
   free(buf);
   return -1;
 }
diff --git a/src/gameglobals.h b/src/gameglobals.h
index ca2747c..76a13fb 100644
--- a/src/gameglobals.h
+++ b/src/gameglobals.h
@@ -39,11 +39,13 @@ extern SpriteBank banks[256];
 
 
 enum {
-  LB_GVAR,
+  LB_MIN_TYPE = 0,
+  LB_GVAR = 0,
   LB_TVAR,
   LB_SVAR,
   LB_CODE,
   LB_CONST,
+  LB_MAX_TYPE,
   LB_MARK = -1
 };
 
@@ -53,6 +55,7 @@ typedef struct LabelInfo {
   char *name;
   int type;
   int value;
+  int pub; // public?
 } LabelInfo;
 
 //extern LabelInfo *labels;
@@ -63,6 +66,11 @@ extern void fatal (const char *fmt, ...) __attribute__((__noreturn__)) __attribu
 extern int loadVMCode (ResFile *resfile, int pc);
 
 extern void freeLabels (void);
+extern void freeLabelsUntilMark (void);
+
+extern void labelAddMark (void);
+extern LabelInfo *addLabel (const char *name, int type, int value, int pub);
+
 extern LabelInfo *findLabel (const char *name);
 
 extern int findPC (const char *name);
-- 
2.11.4.GIT