2.9BSD/usr/include/sys/trap.h

/*
 * Trap type values
 */

#define	BUSFLT		0
#define	INSTRAP		1
#define	BPTTRAP		2
#define	IOTTRAP		3
#define	POWRFAIL	4
#define	EMTTRAP		5
#define	SYSCALL		6
#define	PIRQ		7
#define	ARITHTRAP	8
#define	SEGFLT		9
#define	PARITYFLT	10
#define	SWITCHTRAP	12
#define	RANDOMTRAP	14
#define	ZEROTRAP	15