diff --git a/repos/base/include/x86_64/cpu/cpu_state.h b/repos/base/include/x86_64/cpu/cpu_state.h
index 421a37f85d..0ff1e2706e 100644
--- a/repos/base/include/x86_64/cpu/cpu_state.h
+++ b/repos/base/include/x86_64/cpu/cpu_state.h
@@ -26,12 +26,13 @@ namespace Genode { struct Cpu_state; }
 struct Genode::Cpu_state
 {
 	enum Cpu_exception {
-		NO_MATH_COPROC   = 0x07,
-		PAGE_FAULT       = 0x0e,
-		SUPERVISOR_CALL  = 0x80,
-		INTERRUPTS_START = 0x20,
-		RESET            = 0xfe,
-		INTERRUPTS_END   = 0xff,
+		UNDEFINED_INSTRUCTION = 0x06,
+		NO_MATH_COPROC        = 0x07,
+		PAGE_FAULT            = 0x0e,
+		SUPERVISOR_CALL       = 0x80,
+		INTERRUPTS_START      = 0x20,
+		RESET                 = 0xfe,
+		INTERRUPTS_END        = 0xff,
 	};
 
 	addr_t ip      = 0;