Providing indirect data addressing in an input/output processing system where the indirect data address list is non-contiguous

摘要

A method includes configuring a processing circuit to perform: receiving a control word for an I/O operation, forwarding a transport command control block (TCCB) from the channel subsystem to a control unit, gathering data associated with the I/O operation, and transmitting the gathered data to the control unit in the I/O processing system. Gathering the data includes accessing entries of a list of storage addresses that collectively specifying the data. Based on an entry of the list comprising a not-set first flag and a corresponding first storage address, gathering data from a corresponding storage location, and based on an entry of the list comprising a set first flag and a corresponding second storage address, obtaining a next entry of the list from a second storage location.

主权项

1. A method of creating a circuit, comprising:
configuring a processing circuit to perform:
receiving a control word for an input/output (I/O) operation, the control word including an indirect data address for data associated with the I/O operation, the indirect data address including a starting location of a list of storage addresses that collectively specify the data;forwarding a transport command control block (TCCB) from a channel subsystem to a control unit controlling an I/O device for executing the I/O operation, the TCCB including at least one device control word (DCW) and the TCCB being obtained by a location identified by a transport control word (TCW);gathering the data, wherein gathering comprises accessing entries of the list until a last entry is accessed, wherein accessing includes 1) and 2):1) based on an entry of the list comprising a not-set first flag and a corresponding first storage address, gathering data from a corresponding storage location; and2) based on an entry of the list comprising a set first flag and a corresponding second storage address, obtaining a next entry of the list from a second storage location, wherein the second storage address is located contiguously to the first storage address when an entry of the list comprises the not-set first flag, and the second storage address is located non-contiguously to the first storage address when an entry of the list comprises the set first flag; andtransmitting the gathered data to the control unit.