--- nono/m88xx0/m88100subr.cpp	2026/04/29 17:04:38	1.1.1.3
+++ nono/m88xx0/m88100subr.cpp	2026/04/29 17:04:41	1.1.1.4
@@ -72,9 +72,26 @@ m88kcpu::SetVersion(uint32 version)
 /*static*/ const char *
 m88kcpu::GetExceptionName(int vector)
 {
-	if (0 < vector && vector < countof(exception_names)) {
+	if (0 <= vector && vector < countof(exception_names)) {
 		return exception_names[vector];
 	}
 
+	// OpenBSD
+	// XXX 本来は OpenBSD 稼働時に限定すべきだろうけど、そうする意味もない
+	switch (vector) {
+	 case 450:
+		return "OpenBSD system call";
+	 case 451:
+		return "OpenBSD cache flush";
+	 case 503:
+		return "Division by zero in GCC";
+	 case 504:
+		return "OpenBSD stepbpt";
+	 case 511:
+		return "OpenBSD userbpt";
+	 default:
+		break;
+	}
+
 	return NULL;
 }