diff --git a/mps/code/amcss.c b/mps/code/amcss.c
index bc0d8861149..9af1670acfd 100644
--- a/mps/code/amcss.c
+++ b/mps/code/amcss.c
@@ -45,14 +45,14 @@ static mps_ap_t ap;
 static mps_addr_t exactRoots[exactRootsCOUNT];
 static mps_addr_t ambigRoots[ambigRootsCOUNT];
 static size_t scale;            /* Overall scale factor. */
+static unsigned long nCollsStart;
+static unsigned long nCollsDone;
 
 
 /* report -- report statistics from any messages */
 
 static void report(mps_arena_t arena)
 {
-  static int nCollsStart = 0;
-  static int nCollsDone = 0;
   mps_message_type_t type;
     
   while(mps_message_queue_type(&type, arena)) {
@@ -62,7 +62,7 @@ static void report(mps_arena_t arena)
 
     if (type == mps_message_type_gc_start()) {
       nCollsStart += 1;
-      printf("\n{\n  Collection %d started.  Because:\n", nCollsStart);
+      printf("\n{\n  Collection %lu started.  Because:\n", nCollsStart);
       printf("    %s\n", mps_message_gc_start_why(arena, message));
       printf("    clock: %"PRIuLONGEST"\n", (ulongest_t)mps_message_clock(arena, message));
 
@@ -74,7 +74,7 @@ static void report(mps_arena_t arena)
       condemned = mps_message_gc_condemned_size(arena, message);
       not_condemned = mps_message_gc_not_condemned_size(arena, message);
 
-      printf("\n  Collection %d finished:\n", nCollsDone);
+      printf("\n  Collection %lu finished:\n", nCollsDone);
       printf("    live %"PRIuLONGEST"\n", (ulongest_t)live);
       printf("    condemned %"PRIuLONGEST"\n", (ulongest_t)condemned);
       printf("    not_condemned %"PRIuLONGEST"\n", (ulongest_t)not_condemned);
@@ -167,6 +167,8 @@ static void test(mps_arena_t arena, mps_pool_class_t pool_class,
   /* create an ap, and leave it busy */
   die(mps_reserve(&busy_init, busy_ap, 64), "mps_reserve busy");
 
+  nCollsStart = 0;
+  nCollsDone = 0;
   collections = 0;
   rampSwitch = rampSIZE;
   die(mps_ap_alloc_pattern_begin(ap, ramp), "pattern begin (ap)");
@@ -174,20 +176,18 @@ static void test(mps_arena_t arena, mps_pool_class_t pool_class,
   ramping = 1;
   objs = 0;
   while (collections < collectionsCOUNT) {
-    mps_word_t c;
     size_t r;
 
-    c = mps_collections(arena);
-    if (collections != c) {
+    report(arena);
+    if (collections != nCollsStart) {
       if (!described) {
         die(ArenaDescribe(arena, mps_lib_get_stdout(), 0), "ArenaDescribe");
         described = TRUE;
       }
-      collections = c;
-      report(arena);
+      collections = nCollsStart;
 
-      printf("%lu objects (mps_collections says: %"PRIuLONGEST")\n", objs,
-             (ulongest_t)c);
+      printf("%lu objects (nCollsStart=%"PRIuLONGEST")\n", objs,
+             (ulongest_t)collections);
 
       /* test mps_arena_has_addr */
       {