ref: c61a3f52dba349bc945cbb765bde84c31b1a3f10
dir: /sys/src/games/blit/dat.h/
extern u32int curpc, irq;
extern int trace, debug;
extern ushort ram[128*1024];
extern int daddr;
extern ushort dstat;
extern uchar invert;
extern int mousex, mousey, mousebut;
extern int vblctr, uartrxctr;
extern int baud;
enum {
	INTKEY = 1,
	INTMOUSE = 2,
	INTUART = 4,
	INTVBL = 8,
};
enum {
	SX = 800,
	SY = 1024,
	FREQ = 8000*1000,
	VBLDIV = FREQ / 60,
};