diff --git a/include/picrin.h b/include/picrin.h
index 6f0184a8..3ddea47e 100644
--- a/include/picrin.h
+++ b/include/picrin.h
@@ -88,10 +88,7 @@ typedef struct {
   int sym_cnt;
   int uniq_sym_cnt;
 
-  xhash global_tbl;
-  pic_value *globals;
-  size_t glen, gcapa;
-
+  xhash globals;
   xhash macros;
 
   pic_value lib_tbl;
diff --git a/include/picrin/config.h b/include/picrin/config.h
index 2acfe0ea..79b8fc3c 100644
--- a/include/picrin/config.h
+++ b/include/picrin/config.h
@@ -26,8 +26,6 @@
 
 /* #define PIC_RESCUE_SIZE 30 */
 
-/* #define PIC_GLOBALS_SIZE 1024 */
-
 /* #define PIC_SYM_POOL_SIZE 128 */
 
 /* #define PIC_IREP_SIZE 8 */
@@ -93,10 +91,6 @@
 # define PIC_RESCUE_SIZE 30
 #endif
 
-#ifndef PIC_GLOBALS_SIZE
-# define PIC_GLOBALS_SIZE 1024
-#endif
-
 #ifndef PIC_SYM_POOL_SIZE
 # define PIC_SYM_POOL_SIZE 128
 #endif
diff --git a/src/codegen.c b/src/codegen.c
index 1dc7e898..1c0c2c21 100644
--- a/src/codegen.c
+++ b/src/codegen.c
@@ -100,7 +100,7 @@ new_analyze_state(pic_state *pic)
   /* push initial scope */
   push_scope(state, pic_nil_value());
 
-  xh_begin(&it, &pic->global_tbl);
+  xh_begin(&it, &pic->globals);
   while (xh_next(&it)) {
     pic_sym sym = xh_key(it.e, pic_sym);
     xv_push(&state->scope->locals, &sym);
@@ -291,20 +291,8 @@ static pic_value
 analyze_global_var(analyze_state *state, pic_sym sym)
 {
   pic_state *pic = state->pic;
-  xh_entry *e;
-  size_t i;
 
-  if ((e = xh_get_int(&pic->global_tbl, sym))) {
-    i = xh_val(e, size_t);
-  }
-  else {
-    i = pic->glen++;
-    if (i >= pic->gcapa) {
-      pic_error(pic, "global table overflow");
-    }
-    xh_put_int(&pic->global_tbl, sym, &i);
-  }
-  return pic_list2(pic, pic_symbol_value(state->sGREF), pic_int_value(i));
+  return pic_list2(pic, pic_symbol_value(state->sGREF), pic_sym_value(sym));
 }
 
 static pic_value
@@ -1096,7 +1084,7 @@ codegen(codegen_state *state, pic_value obj)
   sym = pic_sym(pic_car(pic, obj));
   if (sym == state->sGREF) {
     cxt->code[cxt->clen].insn = OP_GREF;
-    cxt->code[cxt->clen].u.i = pic_int(pic_list_ref(pic, obj, 1));
+    cxt->code[cxt->clen].u.i = pic_sym(pic_list_ref(pic, obj, 1));
     cxt->clen++;
     return;
   } else if (sym == state->sCREF) {
diff --git a/src/gc.c b/src/gc.c
index bd907524..465704dd 100644
--- a/src/gc.c
+++ b/src/gc.c
@@ -575,8 +575,9 @@ gc_mark_phase(pic_state *pic)
   }
 
   /* global variables */
-  for (i = 0; i < pic->glen; ++i) {
-    gc_mark(pic, pic->globals[i]);
+  xh_begin(&it, &pic->globals);
+  while (xh_next(&it)) {
+    gc_mark(pic, xh_val(it.e, pic_value));
   }
 
   /* macro objects */
diff --git a/src/state.c b/src/state.c
index 518d2ea4..d203f6a2 100644
--- a/src/state.c
+++ b/src/state.c
@@ -49,10 +49,7 @@ pic_open(int argc, char *argv[], char **envp)
   pic->uniq_sym_cnt = 0;
 
   /* global variables */
-  xh_init_int(&pic->global_tbl, sizeof(size_t));
-  pic->globals = (pic_value *)calloc(PIC_GLOBALS_SIZE, sizeof(pic_value));
-  pic->glen = 0;
-  pic->gcapa = PIC_GLOBALS_SIZE;
+  xh_init_int(&pic->globals, sizeof(pic_value));
 
   /* macros */
   xh_init_int(&pic->macros, sizeof(struct pic_macro *));
@@ -164,7 +161,6 @@ pic_close(pic_state *pic)
   pic->ci = pic->cibase;
   pic->arena_idx = 0;
   pic->err = NULL;
-  pic->glen = 0;
   xh_clear(&pic->macros);
   pic->lib_tbl = pic_nil_value();
 
@@ -179,10 +175,9 @@ pic_close(pic_state *pic)
   free(pic->cibase);
 
   /* free global stacks */
-  free(pic->globals);
   free(pic->try_jmps);
   xh_destroy(&pic->syms);
-  xh_destroy(&pic->global_tbl);
+  xh_destroy(&pic->globals);
   xh_destroy(&pic->macros);
   xh_destroy(&pic->rlabels);
 
diff --git a/src/vm.c b/src/vm.c
index 779ed138..1bf62fbe 100644
--- a/src/vm.c
+++ b/src/vm.c
@@ -387,79 +387,38 @@ pic_get_args(pic_state *pic, const char *format, ...)
   return i - 1;
 }
 
-static size_t
-global_ref(pic_state *pic, const char *name)
-{
-  xh_entry *e;
-  pic_sym sym, rename;
-
-  sym = pic_intern_cstr(pic, name);
-  if (! pic_find_rename(pic, pic->lib->env, sym, &rename)) {
-    return SIZE_MAX;
-  }
-  if (! (e = xh_get_int(&pic->global_tbl, rename))) {
-    return SIZE_MAX;
-  }
-  return xh_val(e, size_t);
-}
-
-static size_t
-global_def(pic_state *pic, const char *name)
-{
-  pic_sym sym, rename;
-  size_t gidx;
-
-  sym = pic_intern_cstr(pic, name);
-  if ((gidx = global_ref(pic, name)) != SIZE_MAX) {
-    pic_warn(pic, "redefining global");
-    return gidx;
-  }
-
-  /* register to the senv */
-  rename = pic_add_rename(pic, pic->lib->env, sym);
-
-  /* register to the global table */
-  gidx = pic->glen++;
-  if (pic->glen >= pic->gcapa) {
-    pic_error(pic, "global table overflow");
-  }
-  xh_put_int(&pic->global_tbl, rename, &gidx);
-
-  return gidx;
-}
-
 void
 pic_define(pic_state *pic, const char *name, pic_value val)
 {
+  pic_sym sym, rename;
+
+  sym = pic_intern_cstr(pic, name);
+
+  if (! pic_find_rename(pic, pic->lib->env, sym, &rename)) {
+    rename = pic_add_rename(pic, pic->lib->env, sym);
+  } else {
+    pic_warn(pic, "redefining global");
+  }
+
   /* push to the global arena */
-  pic->globals[global_def(pic, name)] = val;
+  xh_put_int(&pic->globals, rename, &val);
 
   /* export! */
-  pic_export(pic, pic_intern_cstr(pic, name));
+  pic_export(pic, sym);
 }
 
 pic_value
 pic_ref(pic_state *pic, const char *name)
 {
-  size_t gid;
+  pic_sym sym, rename;
 
-  gid = global_ref(pic, name);
-  if (gid == SIZE_MAX) {
+  sym = pic_intern_cstr(pic, name);
+
+  if (! pic_find_rename(pic, pic->lib->env, sym, &rename)) {
     pic_errorf(pic, "symbol \"%s\" not defined", name);
   }
-  return pic->globals[gid];
-}
 
-void
-pic_set(pic_state *pic, const char *name, pic_value value)
-{
-  size_t gid;
-
-  gid = global_ref(pic, name);
-  if (gid == SIZE_MAX) {
-    pic_error(pic, "symbol not defined");
-  }
-  pic->globals[gid] = value;
+  return xh_val(xh_get_int(&pic->globals, rename), pic_value);
 }
 
 pic_value
@@ -675,11 +634,19 @@ pic_apply(pic_state *pic, struct pic_proc *proc, pic_value argv)
       NEXT;
     }
     CASE(OP_GREF) {
-      PUSH(pic->globals[c.u.i]);
+      xh_entry *e;
+
+      if ((e = xh_get_int(&pic->globals, c.u.i)) == NULL) {
+        pic_errorf(pic, "logic flaw; reference to uninitialized global variable: ~s", pic_symbol_name(pic, c.u.i));
+      }
+      PUSH(xh_val(e, pic_value));
       NEXT;
     }
     CASE(OP_GSET) {
-      pic->globals[c.u.i] = POP();
+      pic_value val;
+
+      val = POP();
+      xh_put_int(&pic->globals, c.u.i, &val);
       NEXT;
     }
     CASE(OP_LREF) {