int32 ts_skipf (UNIT *uptr, int32 fc)
{
t_stat st;
t_mtrlnt tbc;
t_bool tmkprv = FALSE;
msgrfc = fc;
if (sim_tape_bot (uptr) && (wchopt & WCH_ENB))
tmkprv = TRUE;
do {
st = sim_tape_sprecf (uptr, &tbc); /* space rec fwd */
if (st == MTSE_TMK) { /* tape mark? */
msgrfc = (msgrfc - 1) & DMASK; /* decr count */
msgxs0 = msgxs0 | XS0_MOT; /* tape has moved */
if (tmkprv && (wchopt & WCH_ESS)) /* 2nd tmk & ESS? */
return (XTC ((msgrfc? XS0_RLS: 0) |
XS0_TMK | XS0_LET, TC2));
tmkprv = TRUE; /* flag tmk */
}
else if (st != MTSE_OK)
return ts_map_status (st);
else tmkprv = FALSE; /* not a tmk */
msgxs0 = msgxs0 | XS0_MOT; /* tape has moved */
} while (msgrfc != 0);
return 0;
}
t_stat mt_reset (DEVICE *dptr)
{
hp_enbdis_pair (dptr, /* make pair cons */
(dptr == &mtd_dev) ? &mtc_dev : &mtd_dev);
if (dptr == &mtc_dev) /* command channel reset? */
mtcio (mtc_dib.devno, ioPOPIO, 0); /* send POPIO signal to command channel */
else /* data channel reset */
mtdio (mtd_dib.devno, ioPOPIO, 0); /* send POPIO signal to data channel */
mtc_fnc = 0;
mtc_1st = mtc_dtf = 0;
sim_cancel (&mtc_unit); /* cancel activity */
sim_tape_reset (&mtc_unit);
if (mtc_unit.flags & UNIT_ATT)
mtc_sta = (sim_tape_bot (&mtc_unit)? STA_BOT: 0) |
(sim_tape_wrp (&mtc_unit)? STA_WLK: 0);
else
mtc_sta = STA_LOCAL | STA_BUSY;
return SCPE_OK;
}
t_stat ts_svc (UNIT *uptr)
{
int32 i, t, bc, fnc, mod, st0, st1;
static const int32 fnc_mod[CMD_N_FNC] = { /* max mod+1 0 ill */
0, 4, 0, 0, 1, 2, 1, 0, /* 00 - 07 */
5, 3, 5, 1, 0, 0, 0, 1, /* 10 - 17 */
0, 0, 0, 0, 0, 0, 0, 0, /* 20 - 27 */
0, 0, 0, 0, 0, 0, 0, 0 /* 30 - 37 */
};
static const int32 fnc_flg[CMD_N_FNC] = {
0, FLG_MO+FLG_AD, 0, 0, 0, FLG_MO+FLG_WR+FLG_AD, FLG_AD, 0,
FLG_MO, FLG_MO+FLG_WR, FLG_MO, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, /* 20 - 27 */
0, 0, 0, 0, 0, 0, 0, 0 /* 30 - 37 */
};
static const char *fnc_name[CMD_N_FNC] = {
"0", "READ", "2", "3", "WCHR", "WRITE", "WSSM", "7",
"POS", "FMT", "CTL", "INIT", "14", "15", "16", "GSTA",
"20", "21", "22", "23", "24", "25", "26", "27",
"30", "31", "32", "33", "34", "35", "36", "37"
};
if (ts_bcmd) { /* boot? */
ts_bcmd = 0; /* clear flag */
sim_tape_rewind (uptr); /* rewind */
if (uptr->flags & UNIT_ATT) { /* attached? */
cmdlnt = cmdadh = cmdadl = 0; /* defang rd */
ts_spacef (uptr, 1, FALSE); /* space fwd */
ts_readf (uptr, 512); /* read blk */
tssr = ts_updtssr (tssr | TSSR_SSR);
}
else tssr = ts_updtssr (tssr | TSSR_SSR | TC3);
if (cmdhdr & CMD_IE)
SET_INT (TS);
return SCPE_OK;
}
if (!(cmdhdr & CMD_ACK)) { /* no acknowledge? */
tssr = ts_updtssr (tssr | TSSR_SSR); /* set rdy, int */
if (cmdhdr & CMD_IE)
SET_INT (TS);
ts_ownc = ts_ownm = 0; /* CPU owns all */
return SCPE_OK;
}
fnc = GET_FNC (cmdhdr); /* get fnc+mode */
mod = GET_MOD (cmdhdr);
if (DEBUG_PRS (ts_dev)) {
fprintf (sim_deb, ">>TS: cmd=%s, mod=%o, buf=%o, lnt=%d, pos=",
fnc_name[fnc], mod, cmdadl, cmdlnt);
fprint_val (sim_deb, ts_unit.pos, 10, T_ADDR_W, PV_LEFT);
fprintf (sim_deb, "\n");
}
if ((fnc != FNC_WCHR) && (tssr & TSSR_NBA)) { /* ~wr chr & nba? */
ts_endcmd (TC3, 0, 0); /* error */
return SCPE_OK;
}
if (ts_qatn && (wchopt & WCH_EAI)) { /* attn pending? */
ts_endcmd (TC1, 0, MSG_MATN | MSG_CATN); /* send attn msg */
SET_INT (TS); /* set interrupt */
ts_qatn = 0; /* not pending */
return SCPE_OK;
}
if (cmdhdr & CMD_CVC) /* cvc? clr vck */
msgxs0 = msgxs0 & ~XS0_VCK;
if ((cmdhdr & CMD_MBZ) || (mod >= fnc_mod[fnc])) { /* test mbz */
ts_endcmd (TC3, XS0_ILC, MSG_ACK | MSG_MILL | MSG_CFAIL);
return SCPE_OK;
}
if ((fnc_flg[fnc] & FLG_MO) && /* mot+(vck|!att)? */
((msgxs0 & XS0_VCK) || !(uptr->flags & UNIT_ATT))) {
ts_endcmd (TC3, XS0_NEF, MSG_ACK | MSG_MNEF | MSG_CFAIL);
return SCPE_OK;
}
if ((fnc_flg[fnc] & FLG_WR) && /* write? */
sim_tape_wrp (uptr)) { /* write lck? */
ts_endcmd (TC3, XS0_WLE | XS0_NEF, MSG_ACK | MSG_MNEF | MSG_CFAIL);
return SCPE_OK;
}
if ((((fnc == FNC_READ) && (mod == 1)) || /* read rev */
((fnc == FNC_POS) && (mod & 1))) && /* space rev */
sim_tape_bot (uptr)) { /* BOT? */
ts_endcmd (TC3, XS0_NEF, MSG_ACK | MSG_MNEF | MSG_CFAIL);
return SCPE_OK;
}
if ((fnc_flg[fnc] & FLG_AD) && (cmdadh & ADDRTEST)) { /* buf addr > 22b? */
ts_endcmd (TC3, XS0_ILA, MSG_ACK | MSG_MILL | MSG_CFAIL);
return SCPE_OK;
}
st0 = st1 = 0;
switch (fnc) { /* case on func */
case FNC_INIT: /* init */
if (!sim_tape_bot (uptr)) /* set if tape moves */
msgxs0 = msgxs0 | XS0_MOT;
sim_tape_rewind (uptr); /* rewind */
case FNC_WSSM: /* write mem */
case FNC_GSTA: /* get status */
ts_endcmd (TC0, 0, MSG_ACK | MSG_CEND); /* send end packet */
return SCPE_OK;
case FNC_WCHR: /* write char */
if ((cmdadh & ADDRTEST) || (cmdadl & 1) || (cmdlnt < 6)) {
ts_endcmd (TSSR_NBA | TC3, XS0_ILA, 0);
break;
}
tsba = (cmdadh << 16) | cmdadl;
bc = ((WCH_PLNT << 1) > cmdlnt)? cmdlnt: WCH_PLNT << 1;
t = Map_ReadW (tsba, bc, cpy_buf); /* fetch packet */
tsba = tsba + (bc - t); /* inc tsba */
if (t) { /* nxm? */
ts_endcmd (TSSR_NBA | TSSR_NXM | TC5, 0, 0);
return SCPE_OK;
}
for (i = 0; i < (bc / 2); i++) /* copy packet */
tswchp[i] = cpy_buf[i];
if ((wchlnt < ((MSG_PLNT - 1) * 2)) || (wchadh & 0177700) || (wchadl & 1))
ts_endcmd (TSSR_NBA | TC3, 0, 0);
else {
msgxs2 = msgxs2 | XS2_XTF | 1;
tssr = ts_updtssr (tssr & ~TSSR_NBA);
ts_endcmd (TC0, 0, MSG_ACK | MSG_CEND);
}
return SCPE_OK;
case FNC_CTL: /* control */
switch (mod) { /* case mode */
case 00: /* msg buf rls */
tssr = ts_updtssr (tssr | TSSR_SSR); /* set SSR */
if (wchopt & WCH_ERI)
SET_INT (TS);
ts_ownc = 0; ts_ownm = 1; /* keep msg */
break;
case 01: /* rewind and unload */
if (!sim_tape_bot (uptr)) /* if tape moves */
msgxs0 = msgxs0 | XS0_MOT;
sim_tape_detach (uptr); /* unload */
ts_endcmd (TC0, 0, MSG_ACK | MSG_CEND);
break;
case 02: /* clean */
ts_endcmd (TC0, 0, MSG_ACK | MSG_CEND); /* nop */
break;
case 03: /* undefined */
ts_endcmd (TC3, XS0_ILC, MSG_ACK | MSG_MILL | MSG_CFAIL);
return SCPE_OK;
case 04: /* rewind */
if (!sim_tape_bot (uptr)) /* if tape moves */
msgxs0 = msgxs0 | XS0_MOT;
sim_tape_rewind (uptr);
ts_endcmd (TC0, XS0_BOT, MSG_ACK | MSG_CEND);
break;
}
break;
case FNC_READ: /* read */
switch (mod) { /* case mode */
case 00: /* fwd */
st0 = ts_readf (uptr, cmdlnt); /* read */
break;
case 01: /* back */
st0 = ts_readr (uptr, cmdlnt); /* read */
break;
case 02: /* reread fwd */
if (cmdhdr & CMD_OPP) { /* opposite? */
st0 = ts_readr (uptr, cmdlnt);
st1 = ts_spacef (uptr, 1, FALSE);
}
else {
st0 = ts_spacer (uptr, 1, FALSE);
st1 = ts_readf (uptr, cmdlnt);
}
break;
case 03: /* reread back */
if (cmdhdr & CMD_OPP) { /* opposite */
st0 = ts_readf (uptr, cmdlnt);
st1 = ts_spacer (uptr, 1, FALSE);
}
else {
st0 = ts_spacef (uptr, 1, FALSE);
st1 = ts_readr (uptr, cmdlnt);
}
break;
}
ts_cmpendcmd (st0, st1);
break;
case FNC_WRIT: /* write */
switch (mod) { /* case mode */
case 00: /* write */
st0 = ts_write (uptr, cmdlnt);
break;
case 01: /* rewrite */
st0 = ts_spacer (uptr, 1, FALSE);
st1 = ts_write (uptr, cmdlnt);
break;
}
ts_cmpendcmd (st0, st1);
break;
case FNC_FMT: /* format */
switch (mod) { /* case mode */
case 00: /* write tmk */
st0 = ts_wtmk (uptr);
break;
case 01: /* erase */
break;
case 02: /* retry tmk */
st0 = ts_spacer (uptr, 1, FALSE);
st1 = ts_wtmk (uptr);
break;
}
ts_cmpendcmd (st0, st1);
break;
case FNC_POS: /* position */
switch (mod) { /* case mode */
case 00: /* space fwd */
st0 = ts_spacef (uptr, cmdadl, TRUE);
break;
case 01: /* space rev */
st0 = ts_spacer (uptr, cmdadl, TRUE);
break;
case 02: /* space ffwd */
st0 = ts_skipf (uptr, cmdadl);
break;
case 03: /* space frev */
st0 = ts_skipr (uptr, cmdadl);
break;
case 04: /* rewind */
if (!sim_tape_bot (uptr)) /* if tape moves */
msgxs0 = msgxs0 | XS0_MOT;
sim_tape_rewind (uptr);
break;
}
ts_cmpendcmd (st0, 0);
break;
}
return SCPE_OK;
}
/* Handle processing of tape requests. */
t_stat mt_srv(UNIT * uptr)
{
int chan = uptr->u5 & MT_CHAN;
int unit = uptr - mt_unit;
int cmd = uptr->u5 & MT_CMD;
DEVICE *dptr = find_dev_from_unit(uptr);
t_mtrlnt reclen;
t_stat r = SCPE_ARG; /* Force error if not set */
uint8 ch;
int mode;
t_mtrlnt loc;
/* Simulate tape load delay */
if (uptr->u5 & MT_LOADED) {
uptr->u5 &= ~MT_LOADED;
uptr->u5 |= MT_BSY|MT_RDY;
sim_debug(DEBUG_DETAIL, dptr, "Unit=%d Loaded\n", unit);
sim_activate(uptr, 50000);
return SCPE_OK;
}
if (uptr->u5 & MT_BSY) {
uptr->u5 &= ~MT_BSY;
sim_debug(DEBUG_DETAIL, dptr, "Unit=%d Online\n", unit);
iostatus |= 1 << (uptr - mt_unit);
if (uptr->u5 & MT_IDLE)
sim_activate(uptr, 50000);
return SCPE_OK;
}
if (uptr->u5 & MT_IDLE) {
uptr->u5 &= ~MT_IDLE;
if (uptr->u5 & MT_RDY) {
sim_debug(DEBUG_DETAIL, dptr, "Unit=%d idling\n", unit);
return SCPE_OK;
}
sim_debug(DEBUG_DETAIL, dptr, "Unit=%d start %02o\n", unit, cmd);
}
switch (cmd) {
/* Handle interrogate */
case MT_INT:
if (sim_tape_wrp(uptr))
chan_set_wrp(chan);
uptr->u5 &= ~(MT_CMD|MT_BIN);
uptr->u5 |= MT_RDY;
chan_set_end(chan);
sim_debug(DEBUG_DETAIL, dptr, "Status\n");
return SCPE_OK;
case MT_RD: /* Read */
/* If at end of record, fill buffer */
if (BUF_EMPTY(uptr)) {
sim_debug(DEBUG_DETAIL, dptr, "Read unit=%d %s ", unit,
(uptr->u5 & MT_BIN)? "bin": "bcd");
if (sim_tape_eot(uptr)) {
sim_activate(uptr, 4000);
return mt_error(uptr, chan, MTSE_EOM, dptr);
}
r = sim_tape_rdrecf(uptr, &mt_buffer[chan][0], &reclen, BUFFSIZE);
if (r != MTSE_OK) {
if (r == MTSE_TMK) {
sim_debug(DEBUG_DETAIL, dptr, "TM\n");
ch = 017;
(void)chan_write_char(chan, &ch, 1);
sim_activate(uptr, 4000);
} else {
sim_debug(DEBUG_DETAIL, dptr, "r=%d\n", r);
sim_activate(uptr, 5000);
}
return mt_error(uptr, chan, r, dptr);
} else {
uptr->u5 &= ~(MT_BOT|MT_EOT);
uptr->hwmark = reclen;
}
sim_debug(DEBUG_DETAIL, dptr, "%d chars\n", uptr->hwmark);
uptr->u6 = 0;
if ((uptr->u5 & MT_BIN) == 0)
mode = 0100;
else
mode = 0;
for (loc = 0; loc < reclen; loc++) {
ch = mt_buffer[chan][loc] & 0177;
if (((parity_table[ch & 077]) ^ (ch & 0100) ^ mode) == 0) {
chan_set_error(chan);
break;
}
}
}
ch = mt_buffer[chan][uptr->u6++] & 0177;
/* 00 characters are not transfered in BCD mode */
if (ch == 0) {
if (((uint32)uptr->u6) >= uptr->hwmark) {
sim_activate(uptr, 4000);
return mt_error(uptr, chan, MTSE_OK, dptr);
} else {
sim_activate(uptr, HT);
return SCPE_OK;
}
}
if (chan_write_char(chan, &ch,
(((uint32)uptr->u6) >= uptr->hwmark) ? 1 : 0)) {
sim_debug(DEBUG_DATA, dptr, "Read unit=%d %d EOR\n", unit,
uptr->hwmark-uptr->u6);
sim_activate(uptr, 4000);
return mt_error(uptr, chan, MTSE_OK, dptr);
} else {
sim_debug(DEBUG_DATA, dptr, "Read data unit=%d %d %03o\n",
unit, uptr->u6, ch);
sim_activate(uptr, HT);
}
return SCPE_OK;
case MT_RDBK: /* Read Backword */
/* If at end of record, fill buffer */
if (BUF_EMPTY(uptr)) {
sim_debug(DEBUG_DETAIL, dptr, "Read back unit=%d %s ", unit,
(uptr->u5 & MT_BIN)? "bin": "bcd");
if (sim_tape_bot(uptr)) {
sim_activate(uptr, 4000);
return mt_error(uptr, chan, MTSE_BOT, dptr);
}
r = sim_tape_rdrecr(uptr, &mt_buffer[chan][0], &reclen, BUFFSIZE);
if (r != MTSE_OK) {
if (r == MTSE_TMK) {
sim_debug(DEBUG_DETAIL, dptr, "TM\n");
ch = 017;
(void)chan_write_char(chan, &ch, 1);
sim_activate(uptr, 4000);
} else {
uptr->u5 |= MT_BSY;
sim_debug(DEBUG_DETAIL, dptr, "r=%d\n", r);
sim_activate(uptr, 100);
}
return mt_error(uptr, chan, r, dptr);
} else {
uptr->u5 &= ~(MT_BOT|MT_EOT);
uptr->hwmark = reclen;
}
sim_debug(DEBUG_DETAIL, dptr, "%d chars\n", uptr->hwmark);
uptr->u6 = uptr->hwmark;
if ((uptr->u5 & MT_BIN) == 0)
mode = 0100;
else
mode = 0;
for (loc = 0; loc < reclen; loc++) {
ch = mt_buffer[chan][loc] & 0177;
if (((parity_table[ch & 077]) ^ (ch & 0100) ^ mode) == 0) {
chan_set_error(chan);
break;
}
}
}
ch = mt_buffer[chan][--uptr->u6] & 0177;
/* 00 characters are not transfered in BCD mode */
if (ch == 0) {
if (uptr->u6 <= 0) {
sim_activate(uptr, 4000);
return mt_error(uptr, chan, MTSE_OK, dptr);
} else {
sim_activate(uptr, HT);
return SCPE_OK;
}
}
if (chan_write_char(chan, &ch, (uptr->u6 > 0) ? 0 : 1)) {
sim_debug(DEBUG_DATA, dptr, "Read back unit=%d %d EOR\n",
unit, uptr->hwmark-uptr->u6);
sim_activate(uptr, 100);
return mt_error(uptr, chan, MTSE_OK, dptr);
} else {
sim_debug(DEBUG_DATA, dptr, "Read back data unit=%d %d %03o\n",
unit, uptr->u6, ch);
sim_activate(uptr, HT);
}
return SCPE_OK;
case MT_WR: /* Write */
/* Check if write protected */
if (uptr->u6 == 0 && sim_tape_wrp(uptr)) {
sim_activate(uptr, 100);
return mt_error(uptr, chan, MTSE_WRP, dptr);
}
if (chan_read_char(chan, &ch,
(uptr->u6 > BUFFSIZE) ? 1 : 0)) {
reclen = uptr->u6;
/* If no transfer, then either erase */
if (reclen == 0) {
sim_debug(DEBUG_DETAIL, dptr, "Erase\n");
r = MTSE_OK;
} else if ((reclen == 1) && (cmd & MT_BIN) == 0 &&
(mt_buffer[chan][0] == 017)) {
/* Check if write rtape mark */
sim_debug(DEBUG_DETAIL, dptr, "Write Mark unit=%d\n", unit);
r = sim_tape_wrtmk(uptr);
} else {
sim_debug(DEBUG_DETAIL, dptr,
"Write unit=%d Block %d %s chars\n", unit, reclen,
(uptr->u5 & MT_BIN)? "bin": "bcd");
r = sim_tape_wrrecf(uptr, &mt_buffer[chan][0], reclen);
}
uptr->u5 &= ~(MT_BOT|MT_EOT);
sim_activate(uptr, 4000);
return mt_error(uptr, chan, r, dptr); /* Record errors */
} else {
/* Copy data to buffer */
ch &= 077;
ch |= parity_table[ch];
if ((uptr->u5 & MT_BIN))
ch ^= 0100;
/* Don't write out even parity zeros */
if (ch != 0)
mt_buffer[chan][uptr->u6++] = ch;
sim_debug(DEBUG_DATA, dptr, "Write data unit=%d %d %03o\n",
unit, uptr->u6, ch);
uptr->hwmark = uptr->u6;
}
sim_activate(uptr, HT);
return SCPE_OK;
case MT_FSR: /* Space forward one record */
if (BUF_EMPTY(uptr)) {
/* If at end of record, fill buffer */
sim_debug(DEBUG_DETAIL, dptr, "Space unit=%d ", unit);
if (sim_tape_eot(uptr)) {
uptr->u5 &= ~MT_BOT;
sim_debug(DEBUG_DETAIL, dptr, "EOT\n");
sim_activate(uptr, 4000);
return mt_error(uptr, chan, MTSE_EOM, dptr);
}
r = sim_tape_rdrecf(uptr, &mt_buffer[chan][0], &reclen, BUFFSIZE);
if (r != MTSE_OK) {
if (r == MTSE_TMK) {
sim_debug(DEBUG_DETAIL, dptr, "TM ");
reclen = 1;
chan_set_eof(chan);
} else {
sim_debug(DEBUG_DETAIL, dptr, "r=%d ", r);
reclen = 10;
}
}
uptr->u5 &= ~(MT_BOT|MT_EOT);
uptr->hwmark = reclen;
sim_debug(DEBUG_DETAIL, dptr, "%d chars\n", uptr->hwmark);
sim_activate(uptr, uptr->hwmark * HT);
return SCPE_OK;
}
sim_activate(uptr, 4000);
return mt_error(uptr, chan, MTSE_OK, dptr);
case MT_BSR: /* Backspace record */
if (BUF_EMPTY(uptr)) {
/* If at end of record, fill buffer */
sim_debug(DEBUG_DETAIL, dptr, "backspace unit=%d ", unit);
if (sim_tape_bot(uptr)) {
sim_debug(DEBUG_DETAIL, dptr, "BOT\n");
sim_activate(uptr, 100);
return mt_error(uptr, chan, MTSE_BOT, dptr);
}
r = sim_tape_rdrecr(uptr, &mt_buffer[chan][0], &reclen, BUFFSIZE);
if (r != MTSE_OK) {
if (r == MTSE_TMK) {
sim_debug(DEBUG_DETAIL, dptr, "TM ");
reclen = 1;
chan_set_eof(chan);
} else {
reclen = 10;
sim_debug(DEBUG_DETAIL, dptr, "r=%d ", r);
}
}
uptr->u5 &= ~(MT_BOT|MT_EOT);
uptr->hwmark = reclen;
sim_debug(DEBUG_DETAIL, dptr, "%d chars\n", uptr->hwmark);
sim_activate(uptr, uptr->hwmark * HT);
return SCPE_OK;
}
sim_activate(uptr, 4000);
return mt_error(uptr, chan, MTSE_OK, dptr);
case MT_REW: /* Rewind */
sim_debug(DEBUG_DETAIL, dptr, "Rewind unit=%d pos=%d\n", unit,
uptr->pos);
uptr->u5 &= ~(MT_CMD | MT_BIN | MT_IDLE | MT_RDY);
uptr->u5 |= MT_BSY|MT_RDY;
iostatus &= ~(1 << (uptr - mt_unit));
sim_activate(uptr, (uptr->pos/100) + 100);
r = sim_tape_rewind(uptr);
uptr->u5 &= ~MT_EOT;
uptr->u5 |= MT_BOT;
chan_set_end(chan);
return r;
}
return mt_error(uptr, chan, r, dptr);
}
t_stat sim_tape_rdlntr (UNIT *uptr, t_mtrlnt *bc)
{
uint8 c;
t_bool all_eof;
uint32 f = MT_GET_FMT (uptr);
t_addr ppos;
t_mtrlnt sbc;
t_tpclnt tpcbc;
MT_CLR_PNU (uptr);
if ((uptr->flags & UNIT_ATT) == 0) /* not attached? */
return MTSE_UNATT;
if (sim_tape_bot (uptr)) /* at BOT? */
return MTSE_BOT;
switch (f) { /* switch on fmt */
case MTUF_F_STD: case MTUF_F_E11:
do {
sim_fseek (uptr->fileref, uptr->pos - sizeof (t_mtrlnt), SEEK_SET);
sim_fread (bc, sizeof (t_mtrlnt), 1, uptr->fileref); /* read rec lnt */
sbc = MTR_L (*bc);
if (ferror (uptr->fileref)) /* error? */
return sim_tape_ioerr (uptr);
if (feof (uptr->fileref)) /* eof? */
return MTSE_EOM;
uptr->pos = uptr->pos - sizeof (t_mtrlnt); /* spc over rec lnt */
if (*bc == MTR_EOM) /* eom? */
return MTSE_EOM;
if (*bc == MTR_TMK) /* tape mark? */
return MTSE_TMK;
if ((*bc & MTR_M_RHGAP) == MTR_RHGAP) { /* half gap? */
uptr->pos = uptr->pos + sizeof (t_mtrlnt) / 2; /* half space rev */
sim_fseek (uptr->fileref, uptr->pos, SEEK_SET); /* resync */
}
else if (*bc != MTR_GAP) {
uptr->pos = uptr->pos - sizeof (t_mtrlnt) - /* spc over record */
((f == MTUF_F_STD)? ((sbc + 1) & ~1): sbc);
sim_fseek (uptr->fileref, uptr->pos + sizeof (t_mtrlnt), SEEK_SET);
}
else if (sim_tape_bot (uptr)) /* backed into BOT? */
return MTSE_BOT;
}
while ((*bc == MTR_GAP) || (*bc == MTR_RHGAP));
break;
case MTUF_F_TPC:
ppos = sim_tape_tpc_fnd (uptr, (t_addr *) uptr->filebuf); /* find prev rec */
sim_fseek (uptr->fileref, ppos, SEEK_SET); /* position */
sim_fread (&tpcbc, sizeof (t_tpclnt), 1, uptr->fileref);
*bc = tpcbc; /* save rec lnt */
if (ferror (uptr->fileref)) /* error? */
return sim_tape_ioerr (uptr);
if (feof (uptr->fileref)) /* eof? */
return MTSE_EOM;
uptr->pos = ppos; /* spc over record */
if (*bc == MTR_TMK) /* tape mark? */
return MTSE_TMK;
sim_fseek (uptr->fileref, uptr->pos + sizeof (t_tpclnt), SEEK_SET);
break;
case MTUF_F_P7B:
for (sbc = 1, all_eof = 1; (t_addr) sbc <= uptr->pos ; sbc++) {
sim_fseek (uptr->fileref, uptr->pos - sbc, SEEK_SET);
sim_fread (&c, sizeof (uint8), 1, uptr->fileref);
if (ferror (uptr->fileref)) /* error? */
return sim_tape_ioerr (uptr);
if (feof (uptr->fileref)) /* eof? */
return MTSE_EOM;
if ((c & P7B_DPAR) != P7B_EOF)
all_eof = 0;
if (c & P7B_SOR) /* start of record? */
break;
}
uptr->pos = uptr->pos - sbc; /* update position */
*bc = sbc; /* save rec lnt */
sim_fseek (uptr->fileref, uptr->pos, SEEK_SET); /* for read */
if (all_eof) /* tape mark? */
return MTSE_TMK;
break;
default:
return MTSE_FMT;
}
return MTSE_OK;
}