diff --git a/VAX/vax730_sys.c b/VAX/vax730_sys.c
index d1a5c107..0353d8e4 100644
--- a/VAX/vax730_sys.c
+++ b/VAX/vax730_sys.c
@@ -77,7 +77,7 @@ t_stat vax730_boot_parse (int32 flag, const char *ptr);
 
 extern int32 iccs_rd (void);
 extern int32 nicr_rd (void);
-extern int32 icr_rd (t_bool interp);
+extern int32 icr_rd (void);
 extern int32 todr_rd (void);
 extern int32 rxcs_rd (void);
 extern int32 rxdb_rd (void);
@@ -235,7 +235,7 @@ switch (rg) {
         break;
 
     case MT_ICR:                                        /* ICR */
-        val = icr_rd (FALSE);
+        val = icr_rd ();
         break;
 
     case MT_TODR:                                       /* TODR */
diff --git a/VAX/vax750_cmi.c b/VAX/vax750_cmi.c
index 9230715b..3dc60dfa 100644
--- a/VAX/vax750_cmi.c
+++ b/VAX/vax750_cmi.c
@@ -96,7 +96,7 @@ t_stat vax750_show_bootdev (FILE *st, UNIT *uptr, int32 val, CONST void *desc);
 
 extern int32 iccs_rd (void);
 extern int32 nicr_rd (void);
-extern int32 icr_rd (t_bool interp);
+extern int32 icr_rd (void);
 extern int32 todr_rd (void);
 extern int32 rxcs_rd (void);
 extern int32 rxdb_rd (void);
@@ -289,7 +289,7 @@ switch (rg) {
         break;
 
     case MT_ICR:                                        /* ICR */
-        val = icr_rd (FALSE);
+        val = icr_rd ();
         break;
 
     case MT_TODR:                                       /* TODR */
diff --git a/VAX/vax860_abus.c b/VAX/vax860_abus.c
index c17e5524..b8667575 100644
--- a/VAX/vax860_abus.c
+++ b/VAX/vax860_abus.c
@@ -121,7 +121,7 @@ extern t_stat (*nexusR[NEXUS_NUM])(int32 *dat, int32 ad, int32 md);
 extern t_stat (*nexusW[NEXUS_NUM])(int32 dat, int32 ad, int32 md);
 extern int32 iccs_rd (void);
 extern int32 nicr_rd (void);
-extern int32 icr_rd (t_bool interp);
+extern int32 icr_rd (void);
 extern int32 todr_rd (void);
 extern int32 rxcs_rd (void);
 extern int32 rxdb_rd (void);
@@ -422,7 +422,7 @@ switch (rg) {
         break;
 
     case MT_ICR:                                        /* ICR */
-        val = icr_rd (FALSE);
+        val = icr_rd ();
         break;
 
     case MT_TODR:                                       /* TODR */