Specifications

Operating System Routines
IOC$REQCOM
IOC$REQCOM
Completes an I/O operation on a device unit, requests I/O postprocessing of the
current request, and starts the next I/O request waiting for the device.
Module
IOSUBNPAG
Macro
REQCOM
Input
Location Contents
R0 First longword of I/O status.
R1 Second longword of I/O status.
R5 Address of UCB.
UCB$L_STS UCB$V_ERLOGIP set if error logging is in progress.
UCB$B_ERTCNT Final error count.
UCB$B_ERTMAX Maximum error retry count.
UCB$L_EMB Address of error message buffer.
UCB$L_IRP Address of IRP.
UCB$B_DEVCLASS DC$_DISK and DC$_TAPE devices are subject to
mount verification checks.
UCB$L_IOQFL Device unit’s pending-I/O queue.
Output
Location Contents
R0 through R3 Destroyed. Other registers (used by the driver’s
start-I/O routine) are destroyed if IOC$INITIATE is
called.
IRP$L_IOST1 First longword of I/O status.
IRP$L_IOST2 Second longword of I/O status.
UCB$L_OPCNT Incremented.
UCB$L_IOQFL Updated.
EMB$W_DV_STS UCB$W_STS.
EMB$B_DV_ERTCNT UCB$B_ERTCNT.
EMB$B_DV_ERTCNT+1 UCB$B_ERTMAX.
EMB$Q_DV_IOSB Quadword of I/O status.
UCB$L_STS UCB$V_BSY and UCB$V_ERLOGIP cleared.
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