diff --git a/src/mzscheme/src/lightning/ppc/funcs.h b/src/mzscheme/src/lightning/ppc/funcs.h
index 82e235a3df..5c0ea813f0 100644
--- a/src/mzscheme/src/lightning/ppc/funcs.h
+++ b/src/mzscheme/src/lightning/ppc/funcs.h
@@ -71,7 +71,7 @@ jit_flush_code(void *start, void *end)
   }
 
   start -= ((long) start) & (cache_line_size - 1);
-  end -= ((long) end - sizeof(long)) & (cache_line_size - 1);
+  end -= ((long) end - 1) & (cache_line_size - 1);
 
   /* Force data cache write-backs */
   for (ddest = (char *) start; ddest <= (char *) end; ddest += cache_line_size) {