pdp11v/usr/src/lib/lib2/PDPht.c

/*	@(#)PDPht.c	1.1	*/

/*
 * TJU16 tape driver
 */

# include <stand.h>
# define HTADDR ((struct device *) 0172440)

cputype = 70;
struct  device {
        int     htcs1;
        int     htwc;
        caddr_t htba;
        int     htfc;
        int     htcs2;
        int     htds;
        int     hter;
        int     htas;
        int     htck;
        int     htdb;
        int     htmr;
        int     htdt;
        int     htsn;
        int     httc;
        int     htbae;          /* 11/70 bus extension */
        int     htcs3;
} *ht_addr = 172440;

# define NUNIT  4

static daddr_t  _eof[NUNIT];

#define GO      01
#define REW     06
#define DCLR    010
#define ERASE   024
#define WEOF    026
#define SFORW   030
#define SREV    032
#define WCOM    060
#define RCOM    070
#define TRE     040000

#define P800    01300           /*  800 + pdp11 mode */
#define P1600   02300           /* 1600 + pdp11 mode */

#define TM      04
#define DRY     0200
#define MOL     010000

static
_tcommand (io, com)
register struct iob *io;
register com; {
        register unit;

        unit = io->i_dp->dt_unit & 03;
        HTADDR->htcs1 = (segflag << 8) | com | GO;
        while ((HTADDR->htds & DRY) == 0);
        if (HTADDR->htds & TM) {
                _eof[unit]++;
                return (0);
        }
        if (HTADDR->htcs1 & TRE)
                return (-1);
        return (HTADDR->htfc + (com == RCOM ? 0 : io->i_cc));
}

_htclose (io)
register struct iob *io; {
        register flag, unit;

        flag = io->i_flgs;
        unit = io->i_dp->dt_unit & 03;
        HTADDR->htfc = 0;
        if (flag & F_WRITE) {
                _tcommand (io, WEOF);
                _tcommand (io, WEOF);
        }
        if ((io->i_dp->dt_unit & 04) == 0)
                _tcommand (io, REW);
        else if (flag & F_WRITE)
                _tcommand (io, SREV);
        else if (!_eof[unit])
                _tcommand (io, SFORW);
        _eof[unit] = 0;
}

_htstrategy (io, func)
register struct iob *io; {
        register com, unit;
        int errcnt = 0;
        int den, dev;
        int ret;

        dev = io->i_dp->dt_unit;
        HTADDR->htcs2 = unit = dev & 03;
        if (func == READ)
                com = RCOM;
        else if (func == WRITE)
                com = WCOM;
        else
                com = func;
        den = ((dev & 010) ? P1600 : P800) | unit;
        if ((HTADDR->httc & 03777) != den)
                HTADDR->httc = den;
        if ((HTADDR->htds & MOL) == 0) {
                _prs ("TU16 unit not ready\n");
                while ((HTADDR->htds & MOL) == 0);
        }
        do {
                HTADDR->htba = io->i_ma;
                HTADDR->htfc = -io->i_cc;
                HTADDR->htwc = -(io->i_cc >> 1);
                _eof[unit] = 0;
                while ((HTADDR->htds & DRY) == 0);
                if ((ret = _tcommand (io, com)) > 0)
                        return (ret);
                HTADDR->htcs1 = TRE | DCLR | GO;
                if (ret == 0)
                        return (0);
                HTADDR->htfc = -1;
                while ((HTADDR->htds & DRY) == 0);
                _tcommand (io, SREV);
                if (com == WCOM) {
                        while ((HTADDR->htds & DRY) == 0);
                        _tcommand (io, ERASE);
                }
        } while (++errcnt < 10);
        errno = EIO;
        return (-1);
}