#/* *//* * TC-11 DECtape driver */#include "../param.h"#include "../conf.h"#include "../buf.h"#include "../user.h"struct {	int	tccsr;	int	tccm;	int	tcwc;	int	tcba;	int	tcdt;};struct	devtab	tctab;char	tcper[8];#define	TCADDR	0177340#define	NTCBLK	578#define	TAPERR	0100000#define	TREV	04000#define	READY	0200#define	IENABLE	0100#define	UPS	0200#define	ENDZ	0100000#define	BLKM	02000#define	ILGOP	010000#define	SELERR	04000#define	SAT	0#define	RNUM	02#define	RDATA	04#define	SST	010#define	WDATA	014#define	GO	01#define	SFORW	1#define	SREV	2#define	SIO	3tcclose(dev){	bflush(dev);	tcper[dev&07] = 0;}tcstrategy(abp)struct buf *abp;{	register struct buf *bp;	bp = abp;	if(bp->b_flags&B_PHYS)		mapalloc(bp);	if(bp->b_blkno >= NTCBLK || tcper[bp->b_dev&07]) {		bp->b_flags =| B_ERROR;		iodone(bp);		return;	}	bp->av_forw = 0;	spl6();	if (tctab.d_actf==0)		tctab.d_actf = bp;	else		tctab.d_actl->av_forw = bp;	tctab.d_actl = bp;	if (tctab.d_active==0)		tcstart();	spl0();}tcstart(){	register struct buf *bp;	register int *tccmp, com;loop:	tccmp = &TCADDR->tccm;	if ((bp = tctab.d_actf) == 0)		return;	if(tcper[bp->b_dev&07]) {		if((tctab.d_actf = bp->av_forw) == 0)			(*tccmp).lobyte = SAT|GO;		bp->b_flags =| B_ERROR;		iodone(bp);		goto loop;	}	if (((*tccmp).hibyte&07) != bp->b_dev.d_minor)		(*tccmp).lobyte = SAT|GO;	tctab.d_errcnt = 20;	tctab.d_active = SFORW;	com = (bp->b_dev.d_minor<<8) | IENABLE|RNUM|GO;	if ((TCADDR->tccsr & UPS) == 0) {		com =| TREV;		tctab.d_active = SREV;	}	*tccmp = com;}tcintr(){	register struct buf *bp;	register int *tccmp;	register int *tcdtp;	tccmp = &TCADDR->tccm;	tcdtp = &TCADDR->tccsr;	bp = tctab.d_actf;	if (*tccmp&TAPERR) {		if((*tcdtp&(ENDZ|BLKM)) == 0)			deverror(bp, *tcdtp, 0);		if(*tcdtp & (ILGOP|SELERR)) {			tcper[bp->b_dev&07]++;			tctab.d_errcnt = 0;		}		*tccmp =& ~TAPERR;		if (--tctab.d_errcnt  <= 0) {			bp->b_flags =| B_ERROR;			goto done;		}		if (*tccmp&TREV) {		setforw:			tctab.d_active = SFORW;			*tccmp =& ~TREV;		} else {		setback:			tctab.d_active = SREV;			*tccmp =| TREV;		}		(*tccmp).lobyte = IENABLE|RNUM|GO;		return;	}	tcdtp = &TCADDR->tcdt;	switch (tctab.d_active) {	case SIO:	done:		tctab.d_active = 0;		if (tctab.d_actf = bp->av_forw)			tcstart();		else			TCADDR->tccm.lobyte = SAT|GO;		iodone(bp);		return;	case SFORW:		if (*tcdtp > bp->b_blkno)			goto setback;		if (*tcdtp < bp->b_blkno)			goto setforw;		*--tcdtp = bp->b_addr;		/* core address */		*--tcdtp = bp->b_wcount;		tccmp->lobyte = ((bp->b_xmem & 03) << 4) | IENABLE|GO		    | (bp->b_flags&B_READ?RDATA:WDATA);		tctab.d_active = SIO;		return;	case SREV:		if (*tcdtp+3 > bp->b_blkno)			goto setback;		goto setforw;	}}