Specifications

System Macros Invoked by Drivers
PURDPR
PURDPR
Purges a UNIBUS adapter buffered data path.
Format
PURDPR
Description
The PURDPR macro calls IOC$PURGDATAP to purge a UNIBUS adapter
buffered data path. A driver within an I/O subsystem configuration that does
not provide buffered data paths may use the PURDPR macro because the purge
operation detects memory parity errors that may have occurred during the
transfer. When the PURDPR macro is invoked, R5 must contain the address of
the UCB.
When PURDPR returns control to its caller, the following registers contain the
following values:
Register Contents
R0 Status of the purge (success or failure)
R1 Contents of data-path register, provided for the use of the driver’s
register-dumping routine
R2 Address of first map register, provided for the use of the driver’s
register-dumping routine
R3 Address of the CRB
2–50