1 files changed, 2 insertions, 1 deletions
diff --git a/mark.c b/mark.c
index 06a1a53e..72fdec6a 100644
--- a/mark.c
+++ b/mark.c
@@ -664,7 +664,8 @@ GC_INNER mse * GC_mark_from(mse *mark_stack_top, mse *mark_stack,
 # ifdef OS2 /* Use untweaked version to circumvent compiler problem */
     while ((word)mark_stack_top >= (word)mark_stack && credit >= 0)
 # else
-    while ((((ptr_t)mark_stack_top - (ptr_t)mark_stack) | credit) >= 0)
+    while (((((word)mark_stack_top - (word)mark_stack) | (word)credit)
+            & SIGNB) == 0)
 # endif
   {
     current_p = mark_stack_top -> mse_start;