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Last minute fix for HP2100 in v3.9-0 release.

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This commit is contained in:
Mark Pizzolato 2012-05-03 12:55:16 -07:00
parent 38e3d58c72
commit 0c0ff2173e
2 changed files with 28 additions and 10 deletions
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35
HP2100/hp_disclib.c
View File

@ -24,7 +24,7 @@
used in advertising or otherwise to promote the sale, use or other dealings
in this Software without prior written authorization from the authors.
28-Mar-12 JDB First release
02-May-12 JDB First release
09-Nov-11 JDB Created disc controller common library from DS simulator
References:
@ -1822,13 +1822,26 @@ return SCPE_OK; /* the read was successf
Implementation notes:
1. The intersector time is required to allow the ICD interface to set the
end-of-data flag before the next sector begins. The CPU must have enough
time to receive the last byte of the current sector and then unaddress
the disc controller before the first byte of the next sector is sent. If
the time is not long enough, the sector address will be incremented twice
(e.g., a 128-word read of sector 0 will terminate with sector 2 as the
next sector instead of sector 1).
1. The CPU indicates the end of a read data transfer to an ICD controller by
untalking the drive. The untalk is done by the driver as soon as the
DCPC completion interrupt is processed. However, the time from the final
DCPC transfer through driver entry to the point where the untalk is
asserted on the bus varies from 80 instructions (RTE-6/VM with OS
microcode and the buffer in the system map) to 152 instructions (RTE-IVB
with the buffer in the user map). The untalk must occur before the start
of the next sector, or the drive will begin the data transfer.
Normally, this is not a problem, as the driver clears the FIFO of any
received data after DCPC completion. However, if the file mask disables
auto-seeking (or the last sector on the drive had been read), then the
controller will indicate an End of Cylinder error if the untalk does not
precede the start of the next sector.
The RTE driver (DVA32) and various utilities that manage the disc
directly (e.g., SWTCH) do not appear to account for these bogus errors.
Therefore, we work around the issue by extending the intersector delay
to allow time for an potential untalk whenever the next access will
require an auto-seek.
*/
static void end_read (CVPTR cvptr, UNIT *uptr)
@ -1838,7 +1851,11 @@ if (cvptr->eod == SET) /* is the end of data in
else { /* reading continues */
uptr->PHASE = start_phase; /* reset to the start phase */
uptr->wait = cvptr->sector_time; /* delay for the intersector time */
if (cvptr->eoc && cvptr->type) /* at the end of the cylinder and ICD controller? */
uptr->wait = DL_EOC_TIME; /* delay for the end-of-cylinder time */
else /* not at EOC or not an ICD controller */
uptr->wait = cvptr->sector_time; /* delay for the intersector time */
}
return;

3
HP2100/hp_disclib.h
View File

@ -24,7 +24,7 @@
used in advertising or otherwise to promote the sale, use or other dealings
in this Software without prior written authorization from the authors.
30-Mar-12 JDB First release
02-May-12 JDB First release
09-Nov-11 JDB Created disc controller common library from DS simulator
@ -53,6 +53,7 @@
/* Default controller times */
#define DL_EOC_TIME 160 /* end-of-cylinder delay time */
#define DL_SEEK_TIME 100 /* seek delay time (per cylinder) */
#define DL_SECTOR_TIME 27 /* intersector delay time */
#define DL_CMD_TIME 3 /* command start delay time */