# define DEBUG debug
/*
 * Elscint (TM) Scintillation Counters driver.
 * written at St. Joseph's Hospital, by Geoff Collyer, 16 Jan 1979.
 */ 

# include "../param.h"
# include "../user.h"
# include "../buf.h"

# define SCPRI 8	/* same as VTPRI */
# define SCADDR 0164100
# define CTRS 3
struct screg {
	int csr;
	int unused;
	struct sctr {
		int low;
		int high;
	} ctr[CTRS];
};

/* hardware bits in csr */ 
# define RUN 0100000	/* zero means HALT */
# define START 0100	/* zero means STOP */
# define RUNBIT 15	/* bit number of RUN */

/* misc. */ 
# define BCDIGIT 017
# define BCDWIDTH 4	/* width of BCDIGIT */
# define READ 0
# define OPEN 1
# define CLOSED 0
# define NO_MORE (-1)
# define STTY 0

long itol();
int scstate CLOSED;

scopen(dev, flag) {
	if(flag != READ || scstate == OPEN) {
		u.u_error = ENXIO;
		return;
	}
	scstate = OPEN;
	SCADDR->csr = 0;	/* HALT, STOP */ 
	SCADDR->csr |= START;
}

scclose(dev, flag) {
	SCADDR->csr = 0;	/* HALT, STOP */ 
	scstate = CLOSED;
}

scsgtty(dev, v)
	int v[3];
{
	if(v != STTY)
		v[0] = (SCADDR->csr>>RUNBIT)&1;
}

scread(dev) {
	long regs[CTRS];
	char *cp;
	register long *rp;
	register struct sctr *scrp;
	register int i;

	rp = regs;
	scrp = &SCADDR->ctr[0];
	spl6();	/* this will only take a minute... */ 
	SCADDR->csr &= ~START;
	for(i = 0; i < CTRS; ++i, ++scrp)
		*rp++ = itol(scrp->high, scrp->low);
	SCADDR->csr |= START;
	spl0();	/* there; that wasn't so bad, now was it? */ 
	for(i = 0; i < CTRS; ++i)
# ifdef DEBUG
{
		printf("sc: %d hi %d\n", i, regs[i].low);
		printf("sc: %d lo %d\n", i, regs[i].high);
# endif
		scbcd(&regs[i]);
# ifdef DEBUG
		printf("sc: %d hi %d\n", i, regs[i].low);
		printf("sc: %d lo %d\n", i, regs[i].high);
		}
# endif
	cp = (char *) regs;
	for(i = 0; i < sizeof regs && passc(*cp++) != NO_MORE; ++i)
		;
}

scbcd(digs)
	register long *digs;
{
	long result, power;

# ifdef DEBUG
	printf("sc: digs=%o\n", digs);
# endif
	power = 1;
	result = 0;
	for(; *digs > 0; *digs >>= BCDWIDTH) {
# ifdef DEBUG
		printf("sc: digit: %d\n", (int) (*digs)&BCDIGIT);
		printf("sc: power: %d\n", (int) power);
# endif
		result += ((*digs)&BCDIGIT)*power;
# ifdef DEBUG
		printf("sc: result: %d\n", (int) result);
# endif
		power *= 10;
	}
	*digs = result;
}