Specifications

Operating System Routines

EXE$QIODRVPKT

Delivers an IRP to the driver’s start-I/O routine or pending-I/O queue, returns

success status in R0, lowers IPL to 0, and returns to the system service

dispatcher.

Module

SYSQIOREQ

Input

Location Contents

R3 Address of IRP

R4 Address of current PCB

R5 Address of UCB

UCB$B_FLCK Fork lock index or fork IPL

UCB$L_STS UCB$V_BSY set if device is busy, clear if device is

idle

UCB$L_IOQFL Address of pending-I/O queue listhead

UCB$W_QLEN Length of pending-I/O queue

Output

UCB$L_STS UCB$V_BSY set

UCB$W_QLEN Incremented

Synchronization

EXE$QIODRVPKT is called by a driver’s FDT routine at IPL$_ASTDEL. It exits

at IPL 0 (normal process IPL).

Description

EXE$QIODRVPKT calls EXE$INSIOQ. EXE$INSIOQ checks the status of the

device and calls either EXE$INSERTIRP or IOC$INITIATE to place the IRP

in the device’s pending-I/O queue or deliver it to the driver’s start-I/O routine,

respectively.

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