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sigma: Fix error handling in MT device channel errors

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Ken's last note led me to look at magtape error handling, and it was
not right. This has resulted in a lot of code changes in sigma_mt.c, but
the changes are mostly mechanical. Instead of trying to be clever and
do channel handling in mt_map_err or at the bottom of the mt_svc
routine, every magtape command now does its own error handling.
This makes the code repetitive, but I hope it is much clearer as a result.
This commit is contained in:
Bob Supnik 2022-07-07 05:46:32 -10:00 • committed by Mark Pizzolato
parent fa0c561c28
commit adfcff49b7
2 changed files with 69 additions and 43 deletions
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1
sigma/sigma_bugs.txt
View file

@ -118,6 +118,7 @@
112. DK: device address must include unit identifier everywhere, for interrupt generation.
113. MT: device address must include unit identifier everywhere, for interrupt generation.
114: RAD: device address must include unit identifier everywhere, for interrupt generation.
115. MT: error handling not consistent.
Diagnostic Notes

111
sigma/sigma_mt.c
View file

@ -25,6 +25,7 @@
mt 7320 and 7322/7323 magnetic tape
03-Jul-22 RMS Fixed error in handling of channel errors (Ken Rector)
02-Jul-22 RMS Fixed bugs in multi-unit operation
07-Jun-22 RMS Removed unused variables (V4)
26-Mar-22 RMS Added extra case points for new MTSE definitions
@ -276,7 +277,20 @@ switch (op) { /* case on op */
return 0;
}
/* Unit service - reconstruct full unit address at entry */
/* Unit service
1. The full unit address must be reconstructed at entry, for use in interrupt/error routines
2. The magtape error library returns status code 'r' that overlaps SCP error codes. mt_map_err
translates/acts upon these code and returns 'st'. This can incude channel error codes,
so mt_chan_err finally resolves the errors to machine-specific actions (UEND) or an
error code to return to SCP.
3. Channel routines always return channel error codes and must invoke mt_chan_err.
4. Tape mark can be encountered on any read or space command. Except for space file,
it is treated as an error and causes a UEND.
The macro CHS_IFERR is TRUE if the error code is a channel error or a fatal SCP error
and FALSE if the error code is a chennel information code or 0.
*/
t_stat mtu_svc (UNIT *uptr)
{
@ -284,14 +298,13 @@ uint32 cmd = uptr->UCMD;
uint32 un = uptr - mt_unit;
uint32 dva = mt_dib.dva | un;
uint32 c;
uint32 st;
int32 t;
t_mtrlnt tbc;
t_stat r;
t_stat r, st;
if (cmd == MCM_INIT) { /* init state */
if ((t = sim_activate_time (uptr + MT_REW)) != 0) { /* rewinding? */
sim_activate (uptr, t); /* retry later */
sim_activate (uptr, t); /* retry when done */
return SCPE_OK;
}
st = chan_get_cmd (dva, &cmd); /* get command */
@ -342,58 +355,75 @@ if ((mt_op[cmd] & O_WRE) && /* write op and */
return SCPE_OK;
}
r = SCPE_OK;
switch (cmd) { /* case on command */
case MCM_SFWR: /* space forward */
if ((r = sim_tape_sprecf (uptr, &tbc))) /* spc rec fwd, err? */
r = mt_map_err (uptr, r); /* map error */
if ((r = sim_tape_sprecf (uptr, &tbc))) { /* spc rec fwd, err? */
st = mt_map_err (uptr, r); /* map error */
if (CHS_IFERR (st)) /* chan or SCP err? */
return mt_chan_err (dva, st); /* uend and stop */
}
break;
case MCM_SBKR: /* space reverse */
if ((r = sim_tape_sprecr (uptr, &tbc))) /* spc rec rev, err? */
r = mt_map_err (uptr, r); /* map error */
if ((r = sim_tape_sprecr (uptr, &tbc))) { /* spc rec rev, err? */
st = mt_map_err (uptr, r); /* map error */
if (CHS_IFERR (st)) /* chan or SCP err? */
return mt_chan_err (dva, st); /* uend and stop */
}
break;
case MCM_SFWF: /* space fwd file */
while ((r = sim_tape_sprecf (uptr, &tbc)) == MTSE_OK) ;
if (r != MTSE_TMK) /* stopped by tmk? */
r = mt_map_err (uptr, r); /* no, map error */
else r = SCPE_OK;
if (r != MTSE_TMK) { /* no tmk? */
st = mt_map_err (uptr, r); /* map error */
if (CHS_IFERR (st)) /* chan or SCP err? */
return mt_chan_err (dva, st); /* uend and stop */
}
break;
case MCM_SBKF: /* space rev file */
while ((r = sim_tape_sprecr (uptr, &tbc)) == MTSE_OK) ;
if (r != MTSE_TMK) /* stopped by tmk? */
r = mt_map_err (uptr, r); /* no, map error */
else r = SCPE_OK;
if (r != MTSE_TMK) { /* no tmk? */
st = mt_map_err (uptr, r); /* map error */
if (CHS_IFERR (st)) /* chan or SCP err? */
return mt_chan_err (dva, st); /* uend and stop */
}
break;
case MCM_WTM: /* write eof */
if ((r = sim_tape_wrtmk (uptr))) /* write tmk, err? */
r = mt_map_err (uptr, r); /* map error */
if ((r = sim_tape_wrtmk (uptr))) { /* write tmk, err? */
st = mt_map_err (uptr, r); /* map error */
if (CHS_IFERR (st)) /* chan or SCP err? */
return mt_chan_err (dva, st); /* uend and stop */
}
uptr->UST |= MTDV_EOF; /* set eof */
break;
case MCM_RWU: /* rewind unload */
r = sim_tape_detach (uptr);
sim_tape_detach (uptr); /* detach tape */
break;
case MCM_REW: /* rewind */
case MCM_RWI: /* rewind and int */
if ((r = sim_tape_rewind (uptr))) /* rewind */
r = mt_map_err (uptr, r); /* map error */
if ((r = sim_tape_rewind (uptr))) { /* rewind */
st = mt_map_err (uptr, r); /* map error */
if (CHS_IFERR (st)) /* chan or SCP err? */
return mt_chan_err (dva, st); /* uend and stop */
}
mt_unit[un + MT_REW].UCMD = uptr->UCMD; /* copy command */
sim_activate (uptr + MT_REW, mt_rwtime); /* sched compl */
break;
case MCM_READ: /* read */
if (mt_blim == 0) { /* first read? */
r = sim_tape_rdrecf (uptr, mt_xb, &mt_blim, MT_MAXFR);
if (r != MTSE_OK) { /* tape error? */
r = mt_map_err (uptr, r); /* map error */
break;
if ((r = sim_tape_rdrecf (uptr, mt_xb, &mt_blim, MT_MAXFR))) {
st = mt_map_err (uptr, r); /* map error */
if (CHS_IFERR (st)) /* chan or SCP err? */
return mt_chan_err (dva, st); /* uend and stop */
}
if (mt_blim == 0) /* no data? */
return mt_chan_err (dva, SCPE_IERR); /* should NOT happen */
mt_bptr = 0; /* init rec ptr */
}
c = mt_xb[mt_bptr++]; /* get char */
@ -411,11 +441,13 @@ switch (cmd) { /* case on command */
case MCM_RDBK: /* read reverse */
if (mt_blim == 0) { /* first read? */
r = sim_tape_rdrecr (uptr, mt_xb, &mt_blim, MT_MAXFR);
if (r != MTSE_OK) { /* tape error? */
r = mt_map_err (uptr, r); /* map error */
break;
if ((r = sim_tape_rdrecr (uptr, mt_xb, &mt_blim, MT_MAXFR))) {
st = mt_map_err (uptr, r); /* map error */
if (CHS_IFERR (st)) /* chan or SCP err? */
return mt_chan_err (dva, st); /* uend and stop */
}
if (mt_blim == 0) /* no data? */
return mt_chan_err (dva, SCPE_IERR); /* should NOT happen */
mt_bptr = mt_blim; /* init rec ptr */
}
c = mt_xb[--mt_bptr]; /* get char */
@ -442,12 +474,14 @@ switch (cmd) { /* case on command */
sim_activate (uptr, mt_time); /* continue thread */
return SCPE_OK;
}
r = mt_flush_buf (uptr); /* flush buffer */
if (r = mt_flush_buf (uptr)) { /* flush buffer */
st = mt_map_err (uptr, r); /* map error */
if (CHS_IFERR (st)) /* chan or SCP err? */
return mt_chan_err (dva, st); /* uend and stop */
}
break;
}
if (r != SCPE_OK) /* error? abort */
return CHS_IFERR(r)? SCPE_OK: r;
uptr->UCMD = MCM_END; /* end state */
sim_activate (uptr, mt_ctime); /* sched ctlr */
return SCPE_OK;
@ -467,16 +501,12 @@ return SCPE_OK;
t_stat mt_flush_buf (UNIT *uptr)
{
t_stat st;
if (mt_blim == 0) /* any output? */
return SCPE_OK;
if ((st = sim_tape_wrrecf (uptr, mt_xb, mt_blim))) /* write, err? */
return mt_map_err (uptr, st); /* map error */
return SCPE_OK;
return sim_tape_wrrecf (uptr, mt_xb, mt_blim); /* write, err? */
}
/* Map tape error status - returns chan error or SCP status */
/* Map tape error status - returns channel inactive, SCPE_OK, or SCP error */
t_stat mt_map_err (UNIT *uptr, t_stat st)
{
@ -491,34 +521,29 @@ switch (st) {
default: /* unknown error*/
chan_set_chf (dva, CHF_XMME); /* set err, fall through */
case MTSE_OK: /* no error */
chan_uen (dva); /* uend */
return SCPE_IERR;
case MTSE_TMK: /* end of file */
case MTSE_EOM: /* end of medium */
uptr->UST |= MTDV_EOF; /* set eof flag */
chan_uen (dva); /* uend */
return CHS_INACTV;
case MTSE_IOERR: /* IO error */
uptr->UST |= MTDV_DTE; /* set DTE flag */
chan_set_chf (dva, CHF_XMDE);
chan_uen (dva); /* uend */
return SCPE_IOERR;
case MTSE_INVRL: /* invalid rec lnt */
uptr->UST |= MTDV_DTE; /* set DTE flag */
chan_set_chf (dva, CHF_XMDE);
chan_uen (dva); /* uend */
return SCPE_MTRLNT;
case MTSE_RECE: /* record in error */
case MTSE_EOM: /* end of medium */
uptr->UST |= MTDV_DTE; /* set DTE flag */
return chan_set_chf (dva, CHF_XMDE); /* possible error */
case MTSE_BOT: /* reverse into BOT */
uptr->UST |= MTDV_BOT; /* set BOT */
chan_uen (dva); /* uend */
return CHS_INACTV;
} /* end switch */