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The routines described in this section generate special cycles on the PCI bus.
Some special cycle routines use the type RegEntryIDPtr to identify device nodes in the device tree, as described in Name Registry Using RegEntryIDPtr lets the system software and the bridge generate the correct PCI special cycle for the target device.
Special cycles on the PCI bus are broadcast-type cycles. They are always long word write actions. If a node interface is provided, the node chosen for these functions should be behind the bridge that defines the PCI bus on which the special cycle occurs.