Specifications

Operating System Routines
EXE$FINISHIO, EXE$FINISHIOC
• Inserts the IRP in the local processor’s I/O postprocessing queue.
• If the queue is empty, requests a software interrupt from the local processor
at IPL$_IOPOST.
This interrupt causes postprocessing to occur before the remaining instructions in
EXE$FINISHIO or EXE$FINISHIOC are executed.
When all I/O postprocessing has been completed, EXE$FINISHIO or
EXE$FINISHIOC regains control and completes the I/O operation as follows:
• Places status SS$_NORMAL in R0
• Lowers IPL to zero
• Issues the RET instruction that restores the original access mode of the
caller of the $QIO system service and returns control to the system service
dispatcher
The image that issued the $QIO receives SS$_NORMAL status in R0, indicating
that the I/O request has completed without device-independent error.
3–29