Specifications

System Macros Invoked by Drivers

DPTAB

Generates a driver prologue table (DPT) in a program section called $$$105_

PROLOGUE.

Format

DPTAB end ,adapter ,[ﬂags=0] ,ucbsize ,[unload] ,[maxunits=8] ,[defunits=1]

,[deliver] ,[vector] ,name [,psect=$$$105_PROLOGUE] [,smp=NO] [,decode]

Parameters

end

Address of the end of the driver.

adapter

Type of adapter (as indicated by the symbols preﬁxed by AT$ deﬁned by the

$DCDEF macro in SYS$LIBRARY:STARLET.MLB). The adapter type can be any

of the following:

UBA UNIBUS adapter or Q22–bus interface

MBA MASSBUS adapter

GENBI Generic VAXBI adapter

DR DR device

NULL No actual device for driver

[ﬂags=0]

Flags used in loading the driver. Drivers use the following ﬂags:

DPT$M_SVP Indicates that the driver requires a permanently

allocated system page. Disk drivers use this SPTE

during ECC correction and when using the system

routines IOC$MOVFRUSER and IOC$MOVTOUSER.

When this ﬂag is set, the driver-loading procedure

allocates a permanent system page-table entry

(SPTE) for the device. It stores an index to the

virtual address of the SPTE in UCB$L_SVPN when

it creates the UCB. A driver can calculate the system

virtual address of the page corresponding to this

index by using the following formula:

16 16

DPT$M_NOUNLOAD Indicates that the driver cannot be reloaded. When

this bit is set, the driver can be unloaded only by

rebooting the system.

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