xref: /plan9-contrib/sys/src/9/vt4/io.h (revision d6dfd9ef91cf0fa8514a249d5f2a550978c19369)
1 enum
2 {
3 	MaxVector=	8,
4 
5 	/* some flags to change polarity and sensitivity */
6 	IRQmask=	0xFF,	/* actual vector address */
7 	IRQactivelow=	1<<8,
8 	IRQedge=	1<<9,
9 	IRQcritical=	1<<10,
10 };
11 
12 #define BUSUNKNOWN	(-1)
13 
14 #define NEXT(x, l)	(((x)+1)%(l))
15 #define PREV(x, l)	(((x) == 0) ? (l)-1: (x)-1)
16