Specifications

Operating System Routines

EXE$FINISHIO, EXE$FINISHIOC

Complete the servicing of an I/O request and return status to the I/O status block

speciﬁed in the request.

Module

SYSQIOREQ

Input

Location Contents

R0 First longword of status for the I/O status block

R1 Second longword of status for the I/O status block

(EXE$FINISHIO only)

R3 Address of IRP

R4 Address of current PCB

R5 Address of UCB

Output

Location Contents

R0 SS$_NORMAL

IRP$L_IOST1 First longword of I/O status

IRP$L_IOST2 Second longword of I/O status (cleared by

EXE$FINISHIOC)

UCB$L_OPCNT Incremented

Synchronization

EXE$FINISHIO and EXE$FINISHIOC execute at their caller’s IPL and raise to

fork IPL, acquiring the associated fork lock in a multiprocessing environment.

As a result, their callers cannot be executing above fork IPL. A driver usually

transfers control to these routines at IPL$_ASTDEL.

EXE$FINISHIO and EXE$FINISHIOC exit at IPL 0 (normal process IPL).

Description

EXE$FINISHIOC clears the contents of R1. Then, EXE$FINISHIO or

EXE$FINISHIOC takes the following steps to complete the processing of the

I/O request:

• Increases the number of I/O operations completed on the current device in the

operation count ﬁeld of the UCB (UCB$L_OPCNT). This task is performed at

fork IPL, holding the associated fork lock in a multiprocessing environment.

• Stores the contents of R0 and R1 in the IRP.

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