Make erlang:unique_integer use ref_ticks

AtomVM has already an internal unique integer that is stored in
GlobalContext, use it, rather than having another unique_integer.

Signed-off-by: Davide Bettio <davide@uninstall.it>

Author: bettio

src/libAtomVM/bif.c

@@ -344,50 +344,9 @@ term bif_erlang_map_get_2(Context *ctx, uint32_t fail_label, term arg1, term arg
     return term_get_map_value(arg2, pos);
 }
 
-#ifdef AVM_NO_SMP
-static int64_t get_unique_monotonic_integer(void)
-{
-    static int64_t unique = 0;
-
-    if (UNLIKELY(unique == INT64_MAX)) {
-        AVM_ABORT();
-    }
-    return unique++;
-}
-
-#elif ATOMIC_LLONG_LOCK_FREE == 2
-
-static int64_t get_unique_monotonic_integer(void)
-{
-    static int64_t ATOMIC unique = 0;
-
-    if (UNLIKELY(unique == INT64_MAX)) {
-        AVM_ABORT();
-    }
-    return unique++;
-}
-#else
-
-static int64_t get_unique_monotonic_integer(void)
-{
-    static int64_t unique = 0;
-    static SpinLock unique_spinlock;
-
-    if (UNLIKELY(unique == INT64_MAX)) {
-        AVM_ABORT();
-    }
-
-    smp_spinlock_lock(&unique_spinlock);
-    int64_t value = unique++;
-    smp_spinlock_unlock(&unique_spinlock);
-    return value;
-}
-
-#endif
-
 term bif_erlang_unique_integer_0(Context *ctx)
 {
-    int64_t value = get_unique_monotonic_integer();
+    int64_t value = globalcontext_get_ref_ticks(ctx->global);
     return term_make_maybe_boxed_int64(value, &ctx->heap);
 }
 
@@ -408,7 +367,7 @@ term bif_erlang_unique_integer_1(Context *ctx, uint32_t fail_label, term arg1)
     //
     // Right now the implementation is backed by increasing counter
     // that always covers both options
-    int64_t value = get_unique_monotonic_integer();
+    int64_t value = globalcontext_get_ref_ticks(ctx->global);
     return term_make_maybe_boxed_int64(value, &ctx->heap);
 }