Specifications

System Macros Invoked by Drivers
SPI$RELEASE_BUS
SPI$RELEASE_BUS
Releases the SCSI bus.
Format
SPI$RELEASE_BUS
Description
The SPI$RELEASE_BUS macro allows the host acting as a target to release
the SCSI bus. The class driver’s callback routine should invoke either
SPI$RELEASE_BUS or SPI$FINISH_COMMAND, but not both, before exiting.
The class driver should use SPI$RELEASE_BUS instead of SPI$FINISH_
COMMAND if it must explicitly send the SCSI status byte and COMMAND
COMPLETE message using SPI$SEND_BYTES, or if it simply wants to drop off
the bus and terminate the thread in certain error conditions.
Inputs to the SPI$RELEASE_BUS macro include the following:
Location Contents
R4 Address of the SPDT
The port driver returns SS$_NORMAL status in R0, destroys R2, and preserves
all other registers.
2–84