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MVME147 SCSI Firmware Entry Points
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6. $FFFE079A (RTE entry)
Note
Within the SCSI firmware, which can stand alone without
the debug monitor, the first six longwords are the branch
table entries referenced above. The hex offsets provided
reside within the non-volatile RAM.
The following are descriptions of the six entry points. For more detailed
descriptions of their use, refer to the Interface Rules for Multiple Callers section
in Chapter 5.
$FFFE077C: COMMAND ENTRY
Branches to FUNNEL entry.
$FFFE0782: REACTIVATION ENTRY
Branches to FUNNEL entry. All preprocessed commands are
activated in the interrupt service routine through software
interrupt.
$FFFE0788: INTERRUPT ENTRY
This entry point is used as the interrupt service routine
address for vectors on the MVME147 module. Vector $45
(offset $114 from VBR) is the WD33C93 interrupt vector used
by the SCSI firmware. Vector $46 (offset $118 from VBR) is the
DMA channel interrupt vector and vector $4B (offset $12C
from VBR) is the software interrupt vector used by the SCSI
firmware to service queued commands.
Note
The SCSI firmware initializes these vectors.
The following intermediate return resumes with an
interrupt which gives
control to the interrupt entry:
$02: WAIT FOR INTERRUPT (OPEN)
Intermediate status indicating that an WD33C93 interrupt
brings the processor control back to the SCSI firmware. The
MVME147 can accept more commands if it is currently
disconnected from the SCSI bus (refer to the SCSI Firmware