diff --git a/sim_defs.h b/sim_defs.h
index 19ac162d..743097c6 100644
--- a/sim_defs.h
+++ b/sim_defs.h
@@ -747,7 +747,10 @@ typedef struct sim_bitfield BITFIELD;
 /* This replaces any references to "assert()" which should never be invoked */
 /* with an expression which causes side effects (i.e. must be executed for */
 /* the program to work correctly) */
-#define ASSURE(_Expression) if (_Expression) {fprintf(stderr, "%s failed at %s line %d\n", #_Expression, __FILE__, __LINE__); abort();} else (void)0
+#define ASSURE(_Expression) if (_Expression) {fprintf(stderr, "%s failed at %s line %d\n", #_Expression, __FILE__, __LINE__); \
+                                              if (sim_log) fprintf(sim_log, "%s failed at %s line %d\n", #_Expression, __FILE__, __LINE__); \
+                                              if (sim_deb) fprintf(sim_deb, "%s failed at %s line %d\n", #_Expression, __FILE__, __LINE__); \
+                                              abort();} else (void)0
 
 /* Asynch/Threaded I/O support */